/*
** 2009 Oct 23
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file is part of the SQLite FTS3 extension module. Specifically,
** this file contains code to insert, update and delete rows from FTS3
** tables. It also contains code to merge FTS3 b-tree segments. Some
** of the sub-routines used to merge segments are also used by the query
** code in fts3.c.
*/
#include "fts3Int.h"
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#define FTS_MAX_APPENDABLE_HEIGHT 16
/*
** When full-text index nodes are loaded from disk, the buffer that they
** are loaded into has the following number of bytes of padding at the end
** of it. i.e. if a full-text index node is 900 bytes in size, then a buffer
** of 920 bytes is allocated for it.
**
** This means that if we have a pointer into a buffer containing node data,
** it is always safe to read up to two varints from it without risking an
** overread, even if the node data is corrupted.
*/
#define FTS3_NODE_PADDING (FTS3_VARINT_MAX*2)
/*
** Under certain circumstances, b-tree nodes (doclists) can be loaded into
** memory incrementally instead of all at once. This can be a big performance
** win (reduced IO and CPU) if SQLite stops calling the virtual table xNext()
** method before retrieving all query results (as may happen, for example,
** if a query has a LIMIT clause).
**
** Incremental loading is used for b-tree nodes FTS3_NODE_CHUNK_THRESHOLD
** bytes and larger. Nodes are loaded in chunks of FTS3_NODE_CHUNKSIZE bytes.
** The code is written so that the hard lower-limit for each of these values
** is 1. Clearly such small values would be inefficient, but can be useful
** for testing purposes.
**
** If this module is built with SQLITE_TEST defined, these constants may
** be overridden at runtime for testing purposes. File fts3_test.c contains
** a Tcl interface to read and write the values.
*/
#ifdef SQLITE_TEST
int test_fts3_node_chunksize = (4*1024);
int test_fts3_node_chunk_threshold = (4*1024)*4;
# define FTS3_NODE_CHUNKSIZE test_fts3_node_chunksize
# define FTS3_NODE_CHUNK_THRESHOLD test_fts3_node_chunk_threshold
#else
# define FTS3_NODE_CHUNKSIZE (4*1024)
# define FTS3_NODE_CHUNK_THRESHOLD (FTS3_NODE_CHUNKSIZE*4)
#endif
/*
** The two values that may be meaningfully bound to the :1 parameter in
** statements SQL_REPLACE_STAT and SQL_SELECT_STAT.
*/
#define FTS_STAT_DOCTOTAL 0
#define FTS_STAT_INCRMERGEHINT 1
#define FTS_STAT_AUTOINCRMERGE 2
/*
** If FTS_LOG_MERGES is defined, call sqlite3_log() to report each automatic
** and incremental merge operation that takes place. This is used for
** debugging FTS only, it should not usually be turned on in production
** systems.
*/
#ifdef FTS3_LOG_MERGES
static void fts3LogMerge(int nMerge, sqlite3_int64 iAbsLevel){
sqlite3_log(SQLITE_OK, "%d-way merge from level %d", nMerge, (int)iAbsLevel);
}
#else
#define fts3LogMerge(x, y)
#endif
typedef struct PendingList PendingList;
typedef struct SegmentNode SegmentNode;
typedef struct SegmentWriter SegmentWriter;
/*
** An instance of the following data structure is used to build doclists
** incrementally. See function fts3PendingListAppend() for details.
*/
struct PendingList {
int nData;
char *aData;
int nSpace;
sqlite3_int64 iLastDocid;
sqlite3_int64 iLastCol;
sqlite3_int64 iLastPos;
};
/*
** Each cursor has a (possibly empty) linked list of the following objects.
*/
struct Fts3DeferredToken {
Fts3PhraseToken *pToken; /* Pointer to corresponding expr token */
int iCol; /* Column token must occur in */
Fts3DeferredToken *pNext; /* Next in list of deferred tokens */
PendingList *pList; /* Doclist is assembled here */
};
/*
** An instance of this structure is used to iterate through the terms on
** a contiguous set of segment b-tree leaf nodes. Although the details of
** this structure are only manipulated by code in this file, opaque handles
** of type Fts3SegReader* are also used by code in fts3.c to iterate through
** terms when querying the full-text index. See functions:
**
** sqlite3Fts3SegReaderNew()
** sqlite3Fts3SegReaderFree()
** sqlite3Fts3SegReaderIterate()
**
** Methods used to manipulate Fts3SegReader structures:
**
** fts3SegReaderNext()
** fts3SegReaderFirstDocid()
** fts3SegReaderNextDocid()
*/
struct Fts3SegReader {
int iIdx; /* Index within level, or 0x7FFFFFFF for PT */
u8 bLookup; /* True for a lookup only */
u8 rootOnly; /* True for a root-only reader */
sqlite3_int64 iStartBlock; /* Rowid of first leaf block to traverse */
sqlite3_int64 iLeafEndBlock; /* Rowid of final leaf block to traverse */
sqlite3_int64 iEndBlock; /* Rowid of final block in segment (or 0) */
sqlite3_int64 iCurrentBlock; /* Current leaf block (or 0) */
char *aNode; /* Pointer to node data (or NULL) */
int nNode; /* Size of buffer at aNode (or 0) */
int nPopulate; /* If >0, bytes of buffer aNode[] loaded */
sqlite3_blob *pBlob; /* If not NULL, blob handle to read node */
Fts3HashElem **ppNextElem;
/* Variables set by fts3SegReaderNext(). These may be read directly
** by the caller. They are valid from the time SegmentReaderNew() returns
** until SegmentReaderNext() returns something other than SQLITE_OK
** (i.e. SQLITE_DONE).
*/
int nTerm; /* Number of bytes in current term */
char *zTerm; /* Pointer to current term */
int nTermAlloc; /* Allocated size of zTerm buffer */
char *aDoclist; /* Pointer to doclist of current entry */
int nDoclist; /* Size of doclist in current entry */
/* The following variables are used by fts3SegReaderNextDocid() to iterate
** through the current doclist (aDoclist/nDoclist).
*/
char *pOffsetList;
int nOffsetList; /* For descending pending seg-readers only */
sqlite3_int64 iDocid;
};
#define fts3SegReaderIsPending(p) ((p)->ppNextElem!=0)
#define fts3SegReaderIsRootOnly(p) ((p)->rootOnly!=0)
/*
** An instance of this structure is used to create a segment b-tree in the
** database. The internal details of this type are only accessed by the
** following functions:
**
** fts3SegWriterAdd()
** fts3SegWriterFlush()
** fts3SegWriterFree()
*/
struct SegmentWriter {
SegmentNode *pTree; /* Pointer to interior tree structure */
sqlite3_int64 iFirst; /* First slot in %_segments written */
sqlite3_int64 iFree; /* Next free slot in %_segments */
char *zTerm; /* Pointer to previous term buffer */
int nTerm; /* Number of bytes in zTerm */
int nMalloc; /* Size of malloc'd buffer at zMalloc */
char *zMalloc; /* Malloc'd space (possibly) used for zTerm */
int nSize; /* Size of allocation at aData */
int nData; /* Bytes of data in aData */
char *aData; /* Pointer to block from malloc() */
i64 nLeafData; /* Number of bytes of leaf data written */
};
/*
** Type SegmentNode is used by the following three functions to create
** the interior part of the segment b+-tree structures (everything except
** the leaf nodes). These functions and type are only ever used by code
** within the fts3SegWriterXXX() family of functions described above.
**
** fts3NodeAddTerm()
** fts3NodeWrite()
** fts3NodeFree()
**
** When a b+tree is written to the database (either as a result of a merge
** or the pending-terms table being flushed), leaves are written into the
** database file as soon as they are completely populated. The interior of
** the tree is assembled in memory and written out only once all leaves have
** been populated and stored. This is Ok, as the b+-tree fanout is usually
** very large, meaning that the interior of the tree consumes relatively
** little memory.
*/
struct SegmentNode {
SegmentNode *pParent; /* Parent node (or NULL for root node) */
SegmentNode *pRight; /* Pointer to right-sibling */
SegmentNode *pLeftmost; /* Pointer to left-most node of this depth */
int nEntry; /* Number of terms written to node so far */
char *zTerm; /* Pointer to previous term buffer */
int nTerm; /* Number of bytes in zTerm */
int nMalloc; /* Size of malloc'd buffer at zMalloc */
char *zMalloc; /* Malloc'd space (possibly) used for zTerm */
int nData; /* Bytes of valid data so far */
char *aData; /* Node data */
};
/*
** Valid values for the second argument to fts3SqlStmt().
*/
#define SQL_DELETE_CONTENT 0
#define SQL_IS_EMPTY 1
#define SQL_DELETE_ALL_CONTENT 2
#define SQL_DELETE_ALL_SEGMENTS 3
#define SQL_DELETE_ALL_SEGDIR 4
#define SQL_DELETE_ALL_DOCSIZE 5
#define SQL_DELETE_ALL_STAT 6
#define SQL_SELECT_CONTENT_BY_ROWID 7
#define SQL_NEXT_SEGMENT_INDEX 8
#define SQL_INSERT_SEGMENTS 9
#define SQL_NEXT_SEGMENTS_ID 10
#define SQL_INSERT_SEGDIR 11
#define SQL_SELECT_LEVEL 12
#define SQL_SELECT_LEVEL_RANGE 13
#define SQL_SELECT_LEVEL_COUNT 14
#define SQL_SELECT_SEGDIR_MAX_LEVEL 15
#define SQL_DELETE_SEGDIR_LEVEL 16
#define SQL_DELETE_SEGMENTS_RANGE 17
#define SQL_CONTENT_INSERT 18
#define SQL_DELETE_DOCSIZE 19
#define SQL_REPLACE_DOCSIZE 20
#define SQL_SELECT_DOCSIZE 21
#define SQL_SELECT_STAT 22
#define SQL_REPLACE_STAT 23
#define SQL_SELECT_ALL_PREFIX_LEVEL 24
#define SQL_DELETE_ALL_TERMS_SEGDIR 25
#define SQL_DELETE_SEGDIR_RANGE 26
#define SQL_SELECT_ALL_LANGID 27
#define SQL_FIND_MERGE_LEVEL 28
#define SQL_MAX_LEAF_NODE_ESTIMATE 29
#define SQL_DELETE_SEGDIR_ENTRY 30
#define SQL_SHIFT_SEGDIR_ENTRY 31
#define SQL_SELECT_SEGDIR 32
#define SQL_CHOMP_SEGDIR 33
#define SQL_SEGMENT_IS_APPENDABLE 34
#define SQL_SELECT_INDEXES 35
#define SQL_SELECT_MXLEVEL 36
#define SQL_SELECT_LEVEL_RANGE2 37
#define SQL_UPDATE_LEVEL_IDX 38
#define SQL_UPDATE_LEVEL 39
/*
** This function is used to obtain an SQLite prepared statement handle
** for the statement identified by the second argument. If successful,
** *pp is set to the requested statement handle and SQLITE_OK returned.
** Otherwise, an SQLite error code is returned and *pp is set to 0.
**
** If argument apVal is not NULL, then it must point to an array with
** at least as many entries as the requested statement has bound
** parameters. The values are bound to the statements parameters before
** returning.
*/
static int fts3SqlStmt(
Fts3Table *p, /* Virtual table handle */
int eStmt, /* One of the SQL_XXX constants above */
sqlite3_stmt **pp, /* OUT: Statement handle */
sqlite3_value **apVal /* Values to bind to statement */
){
const char *azSql[] = {
/* 0 */ "DELETE FROM %Q.'%q_content' WHERE rowid = ?",
/* 1 */ "SELECT NOT EXISTS(SELECT docid FROM %Q.'%q_content' WHERE rowid!=?)",
/* 2 */ "DELETE FROM %Q.'%q_content'",
/* 3 */ "DELETE FROM %Q.'%q_segments'",
/* 4 */ "DELETE FROM %Q.'%q_segdir'",
/* 5 */ "DELETE FROM %Q.'%q_docsize'",
/* 6 */ "DELETE FROM %Q.'%q_stat'",
/* 7 */ "SELECT %s WHERE rowid=?",
/* 8 */ "SELECT (SELECT max(idx) FROM %Q.'%q_segdir' WHERE level = ?) + 1",
/* 9 */ "REPLACE INTO %Q.'%q_segments'(blockid, block) VALUES(?, ?)",
/* 10 */ "SELECT coalesce((SELECT max(blockid) FROM %Q.'%q_segments') + 1, 1)",
/* 11 */ "REPLACE INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",
/* Return segments in order from oldest to newest.*/
/* 12 */ "SELECT idx, start_block, leaves_end_block, end_block, root "
"FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
/* 13 */ "SELECT idx, start_block, leaves_end_block, end_block, root "
"FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?"
"ORDER BY level DESC, idx ASC",
/* 14 */ "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
/* 15 */ "SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
/* 16 */ "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
/* 17 */ "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
/* 18 */ "INSERT INTO %Q.'%q_content' VALUES(%s)",
/* 19 */ "DELETE FROM %Q.'%q_docsize' WHERE docid = ?",
/* 20 */ "REPLACE INTO %Q.'%q_docsize' VALUES(?,?)",
/* 21 */ "SELECT size FROM %Q.'%q_docsize' WHERE docid=?",
/* 22 */ "SELECT value FROM %Q.'%q_stat' WHERE id=?",
/* 23 */ "REPLACE INTO %Q.'%q_stat' VALUES(?,?)",
/* 24 */ "",
/* 25 */ "",
/* 26 */ "DELETE FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
/* 27 */ "SELECT ? UNION SELECT level / (1024 * ?) FROM %Q.'%q_segdir'",
/* This statement is used to determine which level to read the input from
** when performing an incremental merge. It returns the absolute level number
** of the oldest level in the db that contains at least ? segments. Or,
** if no level in the FTS index contains more than ? segments, the statement
** returns zero rows. */
/* 28 */ "SELECT level, count(*) AS cnt FROM %Q.'%q_segdir' "
" GROUP BY level HAVING cnt>=?"
" ORDER BY (level %% 1024) ASC LIMIT 1",
/* Estimate the upper limit on the number of leaf nodes in a new segment
** created by merging the oldest :2 segments from absolute level :1. See
** function sqlite3Fts3Incrmerge() for details. */
/* 29 */ "SELECT 2 * total(1 + leaves_end_block - start_block) "
" FROM %Q.'%q_segdir' WHERE level = ? AND idx < ?",
/* SQL_DELETE_SEGDIR_ENTRY
** Delete the %_segdir entry on absolute level :1 with index :2. */
/* 30 */ "DELETE FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
/* SQL_SHIFT_SEGDIR_ENTRY
** Modify the idx value for the segment with idx=:3 on absolute level :2
** to :1. */
/* 31 */ "UPDATE %Q.'%q_segdir' SET idx = ? WHERE level=? AND idx=?",
/* SQL_SELECT_SEGDIR
** Read a single entry from the %_segdir table. The entry from absolute
** level :1 with index value :2. */
/* 32 */ "SELECT idx, start_block, leaves_end_block, end_block, root "
"FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
/* SQL_CHOMP_SEGDIR
** Update the start_block (:1) and root (:2) fields of the %_segdir
** entry located on absolute level :3 with index :4. */
/* 33 */ "UPDATE %Q.'%q_segdir' SET start_block = ?, root = ?"
"WHERE level = ? AND idx = ?",
/* SQL_SEGMENT_IS_APPENDABLE
** Return a single row if the segment with end_block=? is appendable. Or
** no rows otherwise. */
/* 34 */ "SELECT 1 FROM %Q.'%q_segments' WHERE blockid=? AND block IS NULL",
/* SQL_SELECT_INDEXES
** Return the list of valid segment indexes for absolute level ? */
/* 35 */ "SELECT idx FROM %Q.'%q_segdir' WHERE level=? ORDER BY 1 ASC",
/* SQL_SELECT_MXLEVEL
** Return the largest relative level in the FTS index or indexes. */
/* 36 */ "SELECT max( level %% 1024 ) FROM %Q.'%q_segdir'",
/* Return segments in order from oldest to newest.*/
/* 37 */ "SELECT level, idx, end_block "
"FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ? "
"ORDER BY level DESC, idx ASC",
/* Update statements used while promoting segments */
/* 38 */ "UPDATE OR FAIL %Q.'%q_segdir' SET level=-1,idx=? "
"WHERE level=? AND idx=?",
/* 39 */ "UPDATE OR FAIL %Q.'%q_segdir' SET level=? WHERE level=-1"
};
int rc = SQLITE_OK;
sqlite3_stmt *pStmt;
assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
pStmt = p->aStmt[eStmt];
if( !pStmt ){
char *zSql;
if( eStmt==SQL_CONTENT_INSERT ){
zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName, p->zWriteExprlist);
}else if( eStmt==SQL_SELECT_CONTENT_BY_ROWID ){
zSql = sqlite3_mprintf(azSql[eStmt], p->zReadExprlist);
}else{
zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName);
}
if( !zSql ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3_prepare_v3(p->db, zSql, -1, SQLITE_PREPARE_PERSISTENT,
&pStmt, NULL);
sqlite3_free(zSql);
assert( rc==SQLITE_OK || pStmt==0 );
p->aStmt[eStmt] = pStmt;
}
}
if( apVal ){
int i;
int nParam = sqlite3_bind_parameter_count(pStmt);
for(i=0; rc==SQLITE_OK && i<nParam; i++){
rc = sqlite3_bind_value(pStmt, i+1, apVal[i]);
}
}
*pp = pStmt;
return rc;
}
static int fts3SelectDocsize(
Fts3Table *pTab, /* FTS3 table handle */
sqlite3_int64 iDocid, /* Docid to bind for SQL_SELECT_DOCSIZE */
sqlite3_stmt **ppStmt /* OUT: Statement handle */
){
sqlite3_stmt *pStmt = 0; /* Statement requested from fts3SqlStmt() */
int rc; /* Return code */
rc = fts3SqlStmt(pTab, SQL_SELECT_DOCSIZE, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pStmt, 1, iDocid);
rc = sqlite3_step(pStmt);
if( rc!=SQLITE_ROW || sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB ){
rc = sqlite3_reset(pStmt);
if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
pStmt = 0;
}else{
rc = SQLITE_OK;
}
}
*ppStmt = pStmt;
return rc;
}
int sqlite3Fts3SelectDoctotal(
Fts3Table *pTab, /* Fts3 table handle */
sqlite3_stmt **ppStmt /* OUT: Statement handle */
){
sqlite3_stmt *pStmt = 0;
int rc;
rc = fts3SqlStmt(pTab, SQL_SELECT_STAT, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
if( sqlite3_step(pStmt)!=SQLITE_ROW
|| sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB
){
rc = sqlite3_reset(pStmt);
if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
pStmt = 0;
}
}
*ppStmt = pStmt;
return rc;
}
int sqlite3Fts3SelectDocsize(
Fts3Table *pTab, /* Fts3 table handle */
sqlite3_int64 iDocid, /* Docid to read size data for */
sqlite3_stmt **ppStmt /* OUT: Statement handle */
){
return fts3SelectDocsize(pTab, iDocid, ppStmt);
}
/*
** Similar to fts3SqlStmt(). Except, after binding the parameters in
** array apVal[] to the SQL statement identified by eStmt, the statement
** is executed.
**
** Returns SQLITE_OK if the statement is successfully executed, or an
** SQLite error code otherwise.
*/
static void fts3SqlExec(
int *pRC, /* Result code */
Fts3Table *p, /* The FTS3 table */
int eStmt, /* Index of statement to evaluate */
sqlite3_value **apVal /* Parameters to bind */
){
sqlite3_stmt *pStmt;
int rc;
if( *pRC ) return;
rc = fts3SqlStmt(p, eStmt, &pStmt, apVal);
if( rc==SQLITE_OK ){
sqlite3_step(pStmt);
rc = sqlite3_reset(pStmt);
}
*pRC = rc;
}
/*
** This function ensures that the caller has obtained an exclusive
** shared-cache table-lock on the %_segdir table. This is required before
** writing data to the fts3 table. If this lock is not acquired first, then
** the caller may end up attempting to take this lock as part of committing
** a transaction, causing SQLite to return SQLITE_LOCKED or
** LOCKED_SHAREDCACHEto a COMMIT command.
**
** It is best to avoid this because if FTS3 returns any error when
** committing a transaction, the whole transaction will be rolled back.
** And this is not what users expect when they get SQLITE_LOCKED_SHAREDCACHE.
** It can still happen if the user locks the underlying tables directly
** instead of accessing them via FTS.
*/
static int fts3Writelock(Fts3Table *p){
int rc = SQLITE_OK;
if( p->nPendingData==0 ){
sqlite3_stmt *pStmt;
rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_null(pStmt, 1);
sqlite3_step(pStmt);
rc = sqlite3_reset(pStmt);
}
}
return rc;
}
/*
** FTS maintains a separate indexes for each language-id (a 32-bit integer).
** Within each language id, a separate index is maintained to store the
** document terms, and each configured prefix size (configured the FTS
** "prefix=" option). And each index consists of multiple levels ("relative
** levels").
**
** All three of these values (the language id, the specific index and the
** level within the index) are encoded in 64-bit integer values stored
** in the %_segdir table on disk. This function is used to convert three
** separate component values into the single 64-bit integer value that
** can be used to query the %_segdir table.
**
** Specifically, each language-id/index combination is allocated 1024
** 64-bit integer level values ("absolute levels"). The main terms index
** for language-id 0 is allocate values 0-1023. The first prefix index
** (if any) for language-id 0 is allocated values 1024-2047. And so on.
** Language 1 indexes are allocated immediately following language 0.
**
** So, for a system with nPrefix prefix indexes configured, the block of
** absolute levels that corresponds to language-id iLangid and index
** iIndex starts at absolute level ((iLangid * (nPrefix+1) + iIndex) * 1024).
*/
static sqlite3_int64 getAbsoluteLevel(
Fts3Table *p, /* FTS3 table handle */
int iLangid, /* Language id */
int iIndex, /* Index in p->aIndex[] */
int iLevel /* Level of segments */
){
sqlite3_int64 iBase; /* First absolute level for iLangid/iIndex */
assert( iLangid>=0 );
assert( p->nIndex>0 );
assert( iIndex>=0 && iIndex<p->nIndex );
iBase = ((sqlite3_int64)iLangid * p->nIndex + iIndex) * FTS3_SEGDIR_MAXLEVEL;
return iBase + iLevel;
}
/*
** Set *ppStmt to a statement handle that may be used to iterate through
** all rows in the %_segdir table, from oldest to newest. If successful,
** return SQLITE_OK. If an error occurs while preparing the statement,
** return an SQLite error code.
**
** There is only ever one instance of this SQL statement compiled for
** each FTS3 table.
**
** The statement returns the following columns from the %_segdir table:
**
** 0: idx
** 1: start_block
** 2: leaves_end_block
** 3: end_block
** 4: root
*/
int sqlite3Fts3AllSegdirs(
Fts3Table *p, /* FTS3 table */
int iLangid, /* Language being queried */
int iIndex, /* Index for p->aIndex[] */
int iLevel, /* Level to select (relative level) */
sqlite3_stmt **ppStmt /* OUT: Compiled statement */
){
int rc;
sqlite3_stmt *pStmt = 0;
assert( iLevel==FTS3_SEGCURSOR_ALL || iLevel>=0 );
assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
assert( iIndex>=0 && iIndex<p->nIndex );
if( iLevel<0 ){
/* "SELECT * FROM %_segdir WHERE level BETWEEN ? AND ? ORDER BY ..." */
rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
sqlite3_bind_int64(pStmt, 2,
getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
);
}
}else{
/* "SELECT * FROM %_segdir WHERE level = ? ORDER BY ..." */
rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex,iLevel));
}
}
*ppStmt = pStmt;
return rc;
}
/*
** Append a single varint to a PendingList buffer. SQLITE_OK is returned
** if successful, or an SQLite error code otherwise.
**
** This function also serves to allocate the PendingList structure itself.
** For example, to create a new PendingList structure containing two
** varints:
**
** PendingList *p = 0;
** fts3PendingListAppendVarint(&p, 1);
** fts3PendingListAppendVarint(&p, 2);
*/
static int fts3PendingListAppendVarint(
PendingList **pp, /* IN/OUT: Pointer to PendingList struct */
sqlite3_int64 i /* Value to append to data */
){
PendingList *p = *pp;
/* Allocate or grow the PendingList as required. */
if( !p ){
p = sqlite3_malloc(sizeof(*p) + 100);
if( !p ){
return SQLITE_NOMEM;
}
p->nSpace = 100;
p->aData = (char *)&p[1];
p->nData = 0;
}
else if( p->nData+FTS3_VARINT_MAX+1>p->nSpace ){
int nNew = p->nSpace * 2;
p = sqlite3_realloc(p, sizeof(*p) + nNew);
if( !p ){
sqlite3_free(*pp);
*pp = 0;
return SQLITE_NOMEM;
}
p->nSpace = nNew;
p->aData = (char *)&p[1];
}
/* Append the new serialized varint to the end of the list. */
p->nData += sqlite3Fts3PutVarint(&p->aData[p->nData], i);
p->aData[p->nData] = '\0';
*pp = p;
return SQLITE_OK;
}
/*
** Add a docid/column/position entry to a PendingList structure. Non-zero
** is returned if the structure is sqlite3_realloced as part of adding
** the entry. Otherwise, zero.
**
** If an OOM error occurs, *pRc is set to SQLITE_NOMEM before returning.
** Zero is always returned in this case. Otherwise, if no OOM error occurs,
** it is set to SQLITE_OK.
*/
static int fts3PendingListAppend(
PendingList **pp, /* IN/OUT: PendingList structure */
sqlite3_int64 iDocid, /* Docid for entry to add */
sqlite3_int64 iCol, /* Column for entry to add */
sqlite3_int64 iPos, /* Position of term for entry to add */
int *pRc /* OUT: Return code */
){
PendingList *p = *pp;
int rc = SQLITE_OK;
assert( !p || p->iLastDocid<=iDocid );
if( !p || p->iLastDocid!=iDocid ){
sqlite3_int64 iDelta = iDocid - (p ? p->iLastDocid : 0);
if( p ){
assert( p->nData<p->nSpace );
assert( p->aData[p->nData]==0 );
p->nData++;
}
if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iDelta)) ){
goto pendinglistappend_out;
}
p->iLastCol = -1;
p->iLastPos = 0;
p->iLastDocid = iDocid;
}
if( iCol>0 && p->iLastCol!=iCol ){
if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, 1))
|| SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iCol))
){
goto pendinglistappend_out;
}
p->iLastCol = iCol;
p->iLastPos = 0;
}
if( iCol>=0 ){
assert( iPos>p->iLastPos || (iPos==0 && p->iLastPos==0) );
rc = fts3PendingListAppendVarint(&p, 2+iPos-p->iLastPos);
if( rc==SQLITE_OK ){
p->iLastPos = iPos;
}
}
pendinglistappend_out:
*pRc = rc;
if( p!=*pp ){
*pp = p;
return 1;
}
return 0;
}
/*
** Free a PendingList object allocated by fts3PendingListAppend().
*/
static void fts3PendingListDelete(PendingList *pList){
sqlite3_free(pList);
}
/*
** Add an entry to one of the pending-terms hash tables.
*/
static int fts3PendingTermsAddOne(
Fts3Table *p,
int iCol,
int iPos,
Fts3Hash *pHash, /* Pending terms hash table to add entry to */
const char *zToken,
int nToken
){
PendingList *pList;
int rc = SQLITE_OK;
pList = (PendingList *)fts3HashFind(pHash, zToken, nToken);
if( pList ){
p->nPendingData -= (pList->nData + nToken + sizeof(Fts3HashElem));
}
if( fts3PendingListAppend(&pList, p->iPrevDocid, iCol, iPos, &rc) ){
if( pList==fts3HashInsert(pHash, zToken, nToken, pList) ){
/* Malloc failed while inserting the new entry. This can only
** happen if there was no previous entry for this token.
*/
assert( 0==fts3HashFind(pHash, zToken, nToken) );
sqlite3_free(pList);
rc = SQLITE_NOMEM;
}
}
if( rc==SQLITE_OK ){
p->nPendingData += (pList->nData + nToken + sizeof(Fts3HashElem));
}
return rc;
}
/*
** Tokenize the nul-terminated string zText and add all tokens to the
** pending-terms hash-table. The docid used is that currently stored in
** p->iPrevDocid, and the column is specified by argument iCol.
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
*/
static int fts3PendingTermsAdd(
Fts3Table *p, /* Table into which text will be inserted */
int iLangid, /* Language id to use */
const char *zText, /* Text of document to be inserted */
int iCol, /* Column into which text is being inserted */
u32 *pnWord /* IN/OUT: Incr. by number tokens inserted */
){
int rc;
int iStart = 0;
int iEnd = 0;
int iPos = 0;
int nWord = 0;
char const *zToken;
int nToken = 0;
sqlite3_tokenizer *pTokenizer = p->pTokenizer;
sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
sqlite3_tokenizer_cursor *pCsr;
int (*xNext)(sqlite3_tokenizer_cursor *pCursor,
const char**,int*,int*,int*,int*);
assert( pTokenizer && pModule );
/* If the user has inserted a NULL value, this function may be called with
** zText==0. In this case, add zero token entries to the hash table and
** return early. */
if( zText==0 ){
*pnWord = 0;
return SQLITE_OK;
}
rc = sqlite3Fts3OpenTokenizer(pTokenizer, iLangid, zText, -1, &pCsr);
if( rc!=SQLITE_OK ){
return rc;
}
xNext = pModule->xNext;
while( SQLITE_OK==rc
&& SQLITE_OK==(rc = xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos))
){
int i;
if( iPos>=nWord ) nWord = iPos+1;
/* Positions cannot be negative; we use -1 as a terminator internally.
** Tokens must have a non-zero length.
*/
if( iPos<0 || !zToken || nToken<=0 ){
rc = SQLITE_ERROR;
break;
}
/* Add the term to the terms index */
rc = fts3PendingTermsAddOne(
p, iCol, iPos, &p->aIndex[0].hPending, zToken, nToken
);
/* Add the term to each of the prefix indexes that it is not too
** short for. */
for(i=1; rc==SQLITE_OK && i<p->nIndex; i++){
struct Fts3Index *pIndex = &p->aIndex[i];
if( nToken<pIndex->nPrefix ) continue;
rc = fts3PendingTermsAddOne(
p, iCol, iPos, &pIndex->hPending, zToken, pIndex->nPrefix
);
}
}
pModule->xClose(pCsr);
*pnWord += nWord;
return (rc==SQLITE_DONE ? SQLITE_OK : rc);
}
/*
** Calling this function indicates that subsequent calls to
** fts3PendingTermsAdd() are to add term/position-list pairs for the
** contents of the document with docid iDocid.
*/
static int fts3PendingTermsDocid(
Fts3Table *p, /* Full-text table handle */
int bDelete, /* True if this op is a delete */
int iLangid, /* Language id of row being written */
sqlite_int64 iDocid /* Docid of row being written */
){
assert( iLangid>=0 );
assert( bDelete==1 || bDelete==0 );
/* TODO(shess) Explore whether partially flushing the buffer on
** forced-flush would provide better performance. I suspect that if
** we ordered the doclists by size and flushed the largest until the
** buffer was half empty, that would let the less frequent terms
** generate longer doclists.
*/
if( iDocid<p->iPrevDocid
|| (iDocid==p->iPrevDocid && p->bPrevDelete==0)
|| p->iPrevLangid!=iLangid
|| p->nPendingData>p->nMaxPendingData
){
int rc = sqlite3Fts3PendingTermsFlush(p);
if( rc!=SQLITE_OK ) return rc;
}
p->iPrevDocid = iDocid;
p->iPrevLangid = iLangid;
p->bPrevDelete = bDelete;
return SQLITE_OK;
}
/*
** Discard the contents of the pending-terms hash tables.
*/
void sqlite3Fts3PendingTermsClear(Fts3Table *p){
int i;
for(i=0; i<p->nIndex; i++){
Fts3HashElem *pElem;
Fts3Hash *pHash = &p->aIndex[i].hPending;
for(pElem=fts3HashFirst(pHash); pElem; pElem=fts3HashNext(pElem)){
PendingList *pList = (PendingList *)fts3HashData(pElem);
fts3PendingListDelete(pList);
}
fts3HashClear(pHash);
}
p->nPendingData = 0;
}
/*
** This function is called by the xUpdate() method as part of an INSERT
** operation. It adds entries for each term in the new record to the
** pendingTerms hash table.
**
** Argument apVal is the same as the similarly named argument passed to
** fts3InsertData(). Parameter iDocid is the docid of the new row.
*/
static int fts3InsertTerms(
Fts3Table *p,
int iLangid,
sqlite3_value **apVal,
u32 *aSz
){
int i; /* Iterator variable */
for(i=2; i<p->nColumn+2; i++){
int iCol = i-2;
if( p->abNotindexed[iCol]==0 ){
const char *zText = (const char *)sqlite3_value_text(apVal[i]);
int rc = fts3PendingTermsAdd(p, iLangid, zText, iCol, &aSz[iCol]);
if( rc!=SQLITE_OK ){
return rc;
}
aSz[p->nColumn] += sqlite3_value_bytes(apVal[i]);
}
}
return SQLITE_OK;
}
/*
** This function is called by the xUpdate() method for an INSERT operation.
** The apVal parameter is passed a copy of the apVal argument passed by
** SQLite to the xUpdate() method. i.e:
**
** apVal[0] Not used for INSERT.
** apVal[1] rowid
** apVal[2] Left-most user-defined column
** ...
** apVal[p->nColumn+1] Right-most user-defined column
** apVal[p->nColumn+2] Hidden column with same name as table
** apVal[p->nColumn+3] Hidden "docid" column (alias for rowid)
** apVal[p->nColumn+4] Hidden languageid column
*/
static int fts3InsertData(
Fts3Table *p, /* Full-text table */
sqlite3_value **apVal, /* Array of values to insert */
sqlite3_int64 *piDocid /* OUT: Docid for row just inserted */
){
int rc; /* Return code */
sqlite3_stmt *pContentInsert; /* INSERT INTO %_content VALUES(...) */
if( p->zContentTbl ){
sqlite3_value *pRowid = apVal[p->nColumn+3];
if( sqlite3_value_type(pRowid)==SQLITE_NULL ){
pRowid = apVal[1];
}
if( sqlite3_value_type(pRowid)!=SQLITE_INTEGER ){
return SQLITE_CONSTRAINT;
}
*piDocid = sqlite3_value_int64(pRowid);
return SQLITE_OK;
}
/* Locate the statement handle used to insert data into the %_content
** table. The SQL for this statement is:
**
** INSERT INTO %_content VALUES(?, ?, ?, ...)
**
** The statement features N '?' variables, where N is the number of user
** defined columns in the FTS3 table, plus one for the docid field.
*/
rc = fts3SqlStmt(p, SQL_CONTENT_INSERT, &pContentInsert, &apVal[1]);
if( rc==SQLITE_OK && p->zLanguageid ){
rc = sqlite3_bind_int(
pContentInsert, p->nColumn+2,
sqlite3_value_int(apVal[p->nColumn+4])
);
}
if( rc!=SQLITE_OK ) return rc;
/* There is a quirk here. The users INSERT statement may have specified
** a value for the "rowid" field, for the "docid" field, or for both.
** Which is a problem, since "rowid" and "docid" are aliases for the
** same value. For example:
**
** INSERT INTO fts3tbl(rowid, docid) VALUES(1, 2);
**
** In FTS3, this is an error. It is an error to specify non-NULL values
** for both docid and some other rowid alias.
*/
if( SQLITE_NULL!=sqlite3_value_type(apVal[3+p->nColumn]) ){
if( SQLITE_NULL==sqlite3_value_type(apVal[0])
&& SQLITE_NULL!=sqlite3_value_type(apVal[1])
){
/* A rowid/docid conflict. */
return SQLITE_ERROR;
}
rc = sqlite3_bind_value(pContentInsert, 1, apVal[3+p->nColumn]);
if( rc!=SQLITE_OK ) return rc;
}
/* Execute the statement to insert the record. Set *piDocid to the
** new docid value.
*/
sqlite3_step(pContentInsert);
rc = sqlite3_reset(pContentInsert);
*piDocid = sqlite3_last_insert_rowid(p->db);
return rc;
}
/*
** Remove all data from the FTS3 table. Clear the hash table containing
** pending terms.
*/
static int fts3DeleteAll(Fts3Table *p, int bContent){
int rc = SQLITE_OK; /* Return code */
/* Discard the contents of the pending-terms hash table. */
sqlite3Fts3PendingTermsClear(p);
/* Delete everything from the shadow tables. Except, leave %_content as
** is if bContent is false. */
assert( p->zContentTbl==0 || bContent==0 );
if( bContent ) fts3SqlExec(&rc, p, SQL_DELETE_ALL_CONTENT, 0);
fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGMENTS, 0);
fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGDIR, 0);
if( p->bHasDocsize ){
fts3SqlExec(&rc, p, SQL_DELETE_ALL_DOCSIZE, 0);
}
if( p->bHasStat ){
fts3SqlExec(&rc, p, SQL_DELETE_ALL_STAT, 0);
}
return rc;
}
/*
**
*/
static int langidFromSelect(Fts3Table *p, sqlite3_stmt *pSelect){
int iLangid = 0;
if( p->zLanguageid ) iLangid = sqlite3_column_int(pSelect, p->nColumn+1);
return iLangid;
}
/*
** The first element in the apVal[] array is assumed to contain the docid
** (an integer) of a row about to be deleted. Remove all terms from the
** full-text index.
*/
static void fts3DeleteTerms(
int *pRC, /* Result code */
Fts3Table *p, /* The FTS table to delete from */
sqlite3_value *pRowid, /* The docid to be deleted */
u32 *aSz, /* Sizes of deleted document written here */
int *pbFound /* OUT: Set to true if row really does exist */
){
int rc;
sqlite3_stmt *pSelect;
assert( *pbFound==0 );
if( *pRC ) return;
rc = fts3SqlStmt(p, SQL_SELECT_CONTENT_BY_ROWID, &pSelect, &pRowid);
if( rc==SQLITE_OK ){
if( SQLITE_ROW==sqlite3_step(pSelect) ){
int i;
int iLangid = langidFromSelect(p, pSelect);
i64 iDocid = sqlite3_column_int64(pSelect, 0);
rc = fts3PendingTermsDocid(p, 1, iLangid, iDocid);
for(i=1; rc==SQLITE_OK && i<=p->nColumn; i++){
int iCol = i-1;
if( p->abNotindexed[iCol]==0 ){
const char *zText = (const char *)sqlite3_column_text(pSelect, i);
rc = fts3PendingTermsAdd(p, iLangid, zText, -1, &aSz[iCol]);
aSz[p->nColumn] += sqlite3_column_bytes(pSelect, i);
}
}
if( rc!=SQLITE_OK ){
sqlite3_reset(pSelect);
*pRC = rc;
return;
}
*pbFound = 1;
}
rc = sqlite3_reset(pSelect);
}else{
sqlite3_reset(pSelect);
}
*pRC = rc;
}
/*
** Forward declaration to account for the circular dependency between
** functions fts3SegmentMerge() and fts3AllocateSegdirIdx().
*/
static int fts3SegmentMerge(Fts3Table *, int, int, int);
/*
** This function allocates a new level iLevel index in the segdir table.
** Usually, indexes are allocated within a level sequentially starting
** with 0, so the allocated index is one greater than the value returned
** by:
**
** SELECT max(idx) FROM %_segdir WHERE level = :iLevel
**
** However, if there are already FTS3_MERGE_COUNT indexes at the requested
** level, they are merged into a single level (iLevel+1) segment and the
** allocated index is 0.
**
** If successful, *piIdx is set to the allocated index slot and SQLITE_OK
** returned. Otherwise, an SQLite error code is returned.
*/
static int fts3AllocateSegdirIdx(
Fts3Table *p,
int iLangid, /* Language id */
int iIndex, /* Index for p->aIndex */
int iLevel,
int *piIdx
){
int rc; /* Return Code */
sqlite3_stmt *pNextIdx; /* Query for next idx at level iLevel */
int iNext = 0; /* Result of query pNextIdx */
assert( iLangid>=0 );
assert( p->nIndex>=1 );
/* Set variable iNext to the next available segdir index at level iLevel. */
rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pNextIdx, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(
pNextIdx, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
);
if( SQLITE_ROW==sqlite3_step(pNextIdx) ){
iNext = sqlite3_column_int(pNextIdx, 0);
}
rc = sqlite3_reset(pNextIdx);
}
if( rc==SQLITE_OK ){
/* If iNext is FTS3_MERGE_COUNT, indicating that level iLevel is already
** full, merge all segments in level iLevel into a single iLevel+1
** segment and allocate (newly freed) index 0 at level iLevel. Otherwise,
** if iNext is less than FTS3_MERGE_COUNT, allocate index iNext.
*/
if( iNext>=FTS3_MERGE_COUNT ){
fts3LogMerge(16, getAbsoluteLevel(p, iLangid, iIndex, iLevel));
rc = fts3SegmentMerge(p, iLangid, iIndex, iLevel);
*piIdx = 0;
}else{
*piIdx = iNext;
}
}
return rc;
}
/*
** The %_segments table is declared as follows:
**
** CREATE TABLE %_segments(blockid INTEGER PRIMARY KEY, block BLOB)
**
** This function reads data from a single row of the %_segments table. The
** specific row is identified by the iBlockid parameter. If paBlob is not
** NULL, then a buffer is allocated using sqlite3_malloc() and populated
** with the contents of the blob stored in the "block" column of the
** identified table row is. Whether or not paBlob is NULL, *pnBlob is set
** to the size of the blob in bytes before returning.
**
** If an error occurs, or the table does not contain the specified row,
** an SQLite error code is returned. Otherwise, SQLITE_OK is returned. If
** paBlob is non-NULL, then it is the responsibility of the caller to
** eventually free the returned buffer.
**
** This function may leave an open sqlite3_blob* handle in the
** Fts3Table.pSegments variable. This handle is reused by subsequent calls
** to this function. The handle may be closed by calling the
** sqlite3Fts3SegmentsClose() function. Reusing a blob handle is a handy
** performance improvement, but the blob handle should always be closed
** before control is returned to the user (to prevent a lock being held
** on the database file for longer than necessary). Thus, any virtual table
** method (xFilter etc.) that may directly or indirectly call this function
** must call sqlite3Fts3SegmentsClose() before returning.
*/
int sqlite3Fts3ReadBlock(
Fts3Table *p, /* FTS3 table handle */
sqlite3_int64 iBlockid, /* Access the row with blockid=$iBlockid */
char **paBlob, /* OUT: Blob data in malloc'd buffer */
int *pnBlob, /* OUT: Size of blob data */
int *pnLoad /* OUT: Bytes actually loaded */
){
int rc; /* Return code */
/* pnBlob must be non-NULL. paBlob may be NULL or non-NULL. */
assert( pnBlob );
if( p->pSegments ){
rc = sqlite3_blob_reopen(p->pSegments, iBlockid);
}else{
if( 0==p->zSegmentsTbl ){
p->zSegmentsTbl = sqlite3_mprintf("%s_segments", p->zName);
if( 0==p->zSegmentsTbl ) return SQLITE_NOMEM;
}
rc = sqlite3_blob_open(
p->db, p->zDb, p->zSegmentsTbl, "block", iBlockid, 0, &p->pSegments
);
}
if( rc==SQLITE_OK ){
int nByte = sqlite3_blob_bytes(p->pSegments);
*pnBlob = nByte;
if( paBlob ){
char *aByte = sqlite3_malloc(nByte + FTS3_NODE_PADDING);
if( !aByte ){
rc = SQLITE_NOMEM;
}else{
if( pnLoad && nByte>(FTS3_NODE_CHUNK_THRESHOLD) ){
nByte = FTS3_NODE_CHUNKSIZE;
*pnLoad = nByte;
}
rc = sqlite3_blob_read(p->pSegments, aByte, nByte, 0);
memset(&aByte[nByte], 0, FTS3_NODE_PADDING);
if( rc!=SQLITE_OK ){
sqlite3_free(aByte);
aByte = 0;
}
}
*paBlob = aByte;
}
}
return rc;
}
/*
** Close the blob handle at p->pSegments, if it is open. See comments above
** the sqlite3Fts3ReadBlock() function for details.
*/
void sqlite3Fts3SegmentsClose(Fts3Table *p){
sqlite3_blob_close(p->pSegments);
p->pSegments = 0;
}
static int fts3SegReaderIncrRead(Fts3SegReader *pReader){
int nRead; /* Number of bytes to read */
int rc; /* Return code */
nRead = MIN(pReader->nNode - pReader->nPopulate, FTS3_NODE_CHUNKSIZE);
rc = sqlite3_blob_read(
pReader->pBlob,
&pReader->aNode[pReader->nPopulate],
nRead,
pReader->nPopulate
);
if( rc==SQLITE_OK ){
pReader->nPopulate += nRead;
memset(&pReader->aNode[pReader->nPopulate], 0, FTS3_NODE_PADDING);
if( pReader->nPopulate==pReader->nNode ){
sqlite3_blob_close(pReader->pBlob);
pReader->pBlob = 0;
pReader->nPopulate = 0;
}
}
return rc;
}
static int fts3SegReaderRequire(Fts3SegReader *pReader, char *pFrom, int nByte){
int rc = SQLITE_OK;
assert( !pReader->pBlob
|| (pFrom>=pReader->aNode && pFrom<&pReader->aNode[pReader->nNode])
);
while( pReader->pBlob && rc==SQLITE_OK
&& (pFrom - pReader->aNode + nByte)>pReader->nPopulate
){
rc = fts3SegReaderIncrRead(pReader);
}
return rc;
}
/*
** Set an Fts3SegReader cursor to point at EOF.
*/
static void fts3SegReaderSetEof(Fts3SegReader *pSeg){
if( !fts3SegReaderIsRootOnly(pSeg) ){
sqlite3_free(pSeg->aNode);
sqlite3_blob_close(pSeg->pBlob);
pSeg->pBlob = 0;
}
pSeg->aNode = 0;
}
/*
** Move the iterator passed as the first argument to the next term in the
** segment. If successful, SQLITE_OK is returned. If there is no next term,
** SQLITE_DONE. Otherwise, an SQLite error code.
*/
static int fts3SegReaderNext(
Fts3Table *p,
Fts3SegReader *pReader,
int bIncr
){
int rc; /* Return code of various sub-routines */
char *pNext; /* Cursor variable */
int nPrefix; /* Number of bytes in term prefix */
int nSuffix; /* Number of bytes in term suffix */
if( !pReader->aDoclist ){
pNext = pReader->aNode;
}else{
pNext = &pReader->aDoclist[pReader->nDoclist];
}
if( !pNext || pNext>=&pReader->aNode[pReader->nNode] ){
if( fts3SegReaderIsPending(pReader) ){
Fts3HashElem *pElem = *(pReader->ppNextElem);
sqlite3_free(pReader->aNode);
pReader->aNode = 0;
if( pElem ){
char *aCopy;
PendingList *pList = (PendingList *)fts3HashData(pElem);
int nCopy = pList->nData+1;
pReader->zTerm = (char *)fts3HashKey(pElem);
pReader->nTerm = fts3HashKeysize(pElem);
aCopy = (char*)sqlite3_malloc(nCopy);
if( !aCopy ) return SQLITE_NOMEM;
memcpy(aCopy, pList->aData, nCopy);
pReader->nNode = pReader->nDoclist = nCopy;
pReader->aNode = pReader->aDoclist = aCopy;
pReader->ppNextElem++;
assert( pReader->aNode );
}
return SQLITE_OK;
}
fts3SegReaderSetEof(pReader);
/* If iCurrentBlock>=iLeafEndBlock, this is an EOF condition. All leaf
** blocks have already been traversed. */
assert( pReader->iCurrentBlock<=pReader->iLeafEndBlock );
if( pReader->iCurrentBlock>=pReader->iLeafEndBlock ){
return SQLITE_OK;
}
rc = sqlite3Fts3ReadBlock(
p, ++pReader->iCurrentBlock, &pReader->aNode, &pReader->nNode,
(bIncr ? &pReader->nPopulate : 0)
);
if( rc!=SQLITE_OK ) return rc;
assert( pReader->pBlob==0 );
if( bIncr && pReader->nPopulate<pReader->nNode ){
pReader->pBlob = p->pSegments;
p->pSegments = 0;
}
pNext = pReader->aNode;
}
assert( !fts3SegReaderIsPending(pReader) );
rc = fts3SegReaderRequire(pReader, pNext, FTS3_VARINT_MAX*2);
if( rc!=SQLITE_OK ) return rc;
/* Because of the FTS3_NODE_PADDING bytes of padding, the following is
** safe (no risk of overread) even if the node data is corrupted. */
pNext += fts3GetVarint32(pNext, &nPrefix);
pNext += fts3GetVarint32(pNext, &nSuffix);
if( nPrefix<0 || nSuffix<=0
|| &pNext[nSuffix]>&pReader->aNode[pReader->nNode]
){
return FTS_CORRUPT_VTAB;
}
if( nPrefix+nSuffix>pReader->nTermAlloc ){
int nNew = (nPrefix+nSuffix)*2;
char *zNew = sqlite3_realloc(pReader->zTerm, nNew);
if( !zNew ){
return SQLITE_NOMEM;
}
pReader->zTerm = zNew;
pReader->nTermAlloc = nNew;
}
rc = fts3SegReaderRequire(pReader, pNext, nSuffix+FTS3_VARINT_MAX);
if( rc!=SQLITE_OK ) return rc;
memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
pReader->nTerm = nPrefix+nSuffix;
pNext += nSuffix;
pNext += fts3GetVarint32(pNext, &pReader->nDoclist);
pReader->aDoclist = pNext;
pReader->pOffsetList = 0;
/* Check that the doclist does not appear to extend past the end of the
** b-tree node. And that the final byte of the doclist is 0x00. If either
** of these statements is untrue, then the data structure is corrupt.
*/
if( &pReader->aDoclist[pReader->nDoclist]>&pReader->aNode[pReader->nNode]
|| (pReader->nPopulate==0 && pReader->aDoclist[pReader->nDoclist-1])
){
return FTS_CORRUPT_VTAB;
}
return SQLITE_OK;
}
/*
** Set the SegReader to point to the first docid in the doclist associated
** with the current term.
*/
static int fts3SegReaderFirstDocid(Fts3Table *pTab, Fts3SegReader *pReader){
int rc = SQLITE_OK;
assert( pReader->aDoclist );
assert( !pReader->pOffsetList );
if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
u8 bEof = 0;
pReader->iDocid = 0;
pReader->nOffsetList = 0;
sqlite3Fts3DoclistPrev(0,
pReader->aDoclist, pReader->nDoclist, &pReader->pOffsetList,
&pReader->iDocid, &pReader->nOffsetList, &bEof
);
}else{
rc = fts3SegReaderRequire(pReader, pReader->aDoclist, FTS3_VARINT_MAX);
if( rc==SQLITE_OK ){
int n = sqlite3Fts3GetVarint(pReader->aDoclist, &pReader->iDocid);
pReader->pOffsetList = &pReader->aDoclist[n];
}
}
return rc;
}
/*
** Advance the SegReader to point to the next docid in the doclist
** associated with the current term.
**
** If arguments ppOffsetList and pnOffsetList are not NULL, then
** *ppOffsetList is set to point to the first column-offset list
** in the doclist entry (i.e. immediately past the docid varint).
** *pnOffsetList is set to the length of the set of column-offset
** lists, not including the nul-terminator byte. For example:
*/
static int fts3SegReaderNextDocid(
Fts3Table *pTab,
Fts3SegReader *pReader, /* Reader to advance to next docid */
char **ppOffsetList, /* OUT: Pointer to current position-list */
int *pnOffsetList /* OUT: Length of *ppOffsetList in bytes */
){
int rc = SQLITE_OK;
char *p = pReader->pOffsetList;
char c = 0;
assert( p );
if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
/* A pending-terms seg-reader for an FTS4 table that uses order=desc.
** Pending-terms doclists are always built up in ascending order, so
** we have to iterate through them backwards here. */
u8 bEof = 0;
if( ppOffsetList ){
*ppOffsetList = pReader->pOffsetList;
*pnOffsetList = pReader->nOffsetList - 1;
}
sqlite3Fts3DoclistPrev(0,
pReader->aDoclist, pReader->nDoclist, &p, &pReader->iDocid,
&pReader->nOffsetList, &bEof
);
if( bEof ){
pReader->pOffsetList = 0;
}else{
pReader->pOffsetList = p;
}
}else{
char *pEnd = &pReader->aDoclist[pReader->nDoclist];
/* Pointer p currently points at the first byte of an offset list. The
** following block advances it to point one byte past the end of
** the same offset list. */
while( 1 ){
/* The following line of code (and the "p++" below the while() loop) is
** normally all that is required to move pointer p to the desired
** position. The exception is if this node is being loaded from disk
** incrementally and pointer "p" now points to the first byte past
** the populated part of pReader->aNode[].
*/
while( *p | c ) c = *p++ & 0x80;
assert( *p==0 );
if( pReader->pBlob==0 || p<&pReader->aNode[pReader->nPopulate] ) break;
rc = fts3SegReaderIncrRead(pReader);
if( rc!=SQLITE_OK ) return rc;
}
p++;
/* If required, populate the output variables with a pointer to and the
** size of the previous offset-list.
*/
if( ppOffsetList ){
*ppOffsetList = pReader->pOffsetList;
*pnOffsetList = (int)(p - pReader->pOffsetList - 1);
}
/* List may have been edited in place by fts3EvalNearTrim() */
while( p<pEnd && *p==0 ) p++;
/* If there are no more entries in the doclist, set pOffsetList to
** NULL. Otherwise, set Fts3SegReader.iDocid to the next docid and
** Fts3SegReader.pOffsetList to point to the next offset list before
** returning.
*/
if( p>=pEnd ){
pReader->pOffsetList = 0;
}else{
rc = fts3SegReaderRequire(pReader, p, FTS3_VARINT_MAX);
if( rc==SQLITE_OK ){
sqlite3_int64 iDelta;
pReader->pOffsetList = p + sqlite3Fts3GetVarint(p, &iDelta);
if( pTab->bDescIdx ){
pReader->iDocid -= iDelta;
}else{
pReader->iDocid += iDelta;
}
}
}
}
return SQLITE_OK;
}
int sqlite3Fts3MsrOvfl(
Fts3Cursor *pCsr,
Fts3MultiSegReader *pMsr,
int *pnOvfl
){
Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
int nOvfl = 0;
int ii;
int rc = SQLITE_OK;
int pgsz = p->nPgsz;
assert( p->bFts4 );
assert( pgsz>0 );
for(ii=0; rc==SQLITE_OK && ii<pMsr->nSegment; ii++){
Fts3SegReader *pReader = pMsr->apSegment[ii];
if( !fts3SegReaderIsPending(pReader)
&& !fts3SegReaderIsRootOnly(pReader)
){
sqlite3_int64 jj;
for(jj=pReader->iStartBlock; jj<=pReader->iLeafEndBlock; jj++){
int nBlob;
rc = sqlite3Fts3ReadBlock(p, jj, 0, &nBlob, 0);
if( rc!=SQLITE_OK ) break;
if( (nBlob+35)>pgsz ){
nOvfl += (nBlob + 34)/pgsz;
}
}
}
}
*pnOvfl = nOvfl;
return rc;
}
/*
** Free all allocations associated with the iterator passed as the
** second argument.
*/
void sqlite3Fts3SegReaderFree(Fts3SegReader *pReader){
if( pReader ){
if( !fts3SegReaderIsPending(pReader) ){
sqlite3_free(pReader->zTerm);
}
if( !fts3SegReaderIsRootOnly(pReader) ){
sqlite3_free(pReader->aNode);
}
sqlite3_blob_close(pReader->pBlob);
}
sqlite3_free(pReader);
}
/*
** Allocate a new SegReader object.
*/
int sqlite3Fts3SegReaderNew(
int iAge, /* Segment "age". */
int bLookup, /* True for a lookup only */
sqlite3_int64 iStartLeaf, /* First leaf to traverse */
sqlite3_int64 iEndLeaf, /* Final leaf to traverse */
sqlite3_int64 iEndBlock, /* Final block of segment */
const char *zRoot, /* Buffer containing root node */
int nRoot, /* Size of buffer containing root node */
Fts3SegReader **ppReader /* OUT: Allocated Fts3SegReader */
){
Fts3SegReader *pReader; /* Newly allocated SegReader object */
int nExtra = 0; /* Bytes to allocate segment root node */
assert( iStartLeaf<=iEndLeaf );
if( iStartLeaf==0 ){
nExtra = nRoot + FTS3_NODE_PADDING;
}
pReader = (Fts3SegReader *)sqlite3_malloc(sizeof(Fts3SegReader) + nExtra);
if( !pReader ){
return SQLITE_NOMEM;
}
memset(pReader, 0, sizeof(Fts3SegReader));
pReader->iIdx = iAge;
pReader->bLookup = bLookup!=0;
pReader->iStartBlock = iStartLeaf;
pReader->iLeafEndBlock = iEndLeaf;
pReader->iEndBlock = iEndBlock;
if( nExtra ){
/* The entire segment is stored in the root node. */
pReader->aNode = (char *)&pReader[1];
pReader->rootOnly = 1;
pReader->nNode = nRoot;
memcpy(pReader->aNode, zRoot, nRoot);
memset(&pReader->aNode[nRoot], 0, FTS3_NODE_PADDING);
}else{
pReader->iCurrentBlock = iStartLeaf-1;
}
*ppReader = pReader;
return SQLITE_OK;
}
/*
** This is a comparison function used as a qsort() callback when sorting
** an array of pending terms by term. This occurs as part of flushing
** the contents of the pending-terms hash table to the database.
*/
static int SQLITE_CDECL fts3CompareElemByTerm(
const void *lhs,
const void *rhs
){
char *z1 = fts3HashKey(*(Fts3HashElem **)lhs);
char *z2 = fts3HashKey(*(Fts3HashElem **)rhs);
int n1 = fts3HashKeysize(*(Fts3HashElem **)lhs);
int n2 = fts3HashKeysize(*(Fts3HashElem **)rhs);
int n = (n1<n2 ? n1 : n2);
int c = memcmp(z1, z2, n);
if( c==0 ){
c = n1 - n2;
}
return c;
}
/*
** This function is used to allocate an Fts3SegReader that iterates through
** a subset of the terms stored in the Fts3Table.pendingTerms array.
**
** If the isPrefixIter parameter is zero, then the returned SegReader iterates
** through each term in the pending-terms table. Or, if isPrefixIter is
** non-zero, it iterates through each term and its prefixes. For example, if
** the pending terms hash table contains the terms "sqlite", "mysql" and
** "firebird", then the iterator visits the following 'terms' (in the order
** shown):
**
** f fi fir fire fireb firebi firebir firebird
** m my mys mysq mysql
** s sq sql sqli sqlit sqlite
**
** Whereas if isPrefixIter is zero, the terms visited are:
**
** firebird mysql sqlite
*/
int sqlite3Fts3SegReaderPending(
Fts3Table *p, /* Virtual table handle */
int iIndex, /* Index for p->aIndex */
const char *zTerm, /* Term to search for */
int nTerm, /* Size of buffer zTerm */
int bPrefix, /* True for a prefix iterator */
Fts3SegReader **ppReader /* OUT: SegReader for pending-terms */
){
Fts3SegReader *pReader = 0; /* Fts3SegReader object to return */
Fts3HashElem *pE; /* Iterator variable */
Fts3HashElem **aElem = 0; /* Array of term hash entries to scan */
int nElem = 0; /* Size of array at aElem */
int rc = SQLITE_OK; /* Return Code */
Fts3Hash *pHash;
pHash = &p->aIndex[iIndex].hPending;
if( bPrefix ){
int nAlloc = 0; /* Size of allocated array at aElem */
for(pE=fts3HashFirst(pHash); pE; pE=fts3HashNext(pE)){
char *zKey = (char *)fts3HashKey(pE);
int nKey = fts3HashKeysize(pE);
if( nTerm==0 || (nKey>=nTerm && 0==memcmp(zKey, zTerm, nTerm)) ){
if( nElem==nAlloc ){
Fts3HashElem **aElem2;
nAlloc += 16;
aElem2 = (Fts3HashElem **)sqlite3_realloc(
aElem, nAlloc*sizeof(Fts3HashElem *)
);
if( !aElem2 ){
rc = SQLITE_NOMEM;
nElem = 0;
break;
}
aElem = aElem2;
}
aElem[nElem++] = pE;
}
}
/* If more than one term matches the prefix, sort the Fts3HashElem
** objects in term order using qsort(). This uses the same comparison
** callback as is used when flushing terms to disk.
*/
if( nElem>1 ){
qsort(aElem, nElem, sizeof(Fts3HashElem *), fts3CompareElemByTerm);
}
}else{
/* The query is a simple term lookup that matches at most one term in
** the index. All that is required is a straight hash-lookup.
**
** Because the stack address of pE may be accessed via the aElem pointer
** below, the "Fts3HashElem *pE" must be declared so that it is valid
** within this entire function, not just this "else{...}" block.
*/
pE = fts3HashFindElem(pHash, zTerm, nTerm);
if( pE ){
aElem = &pE;
nElem = 1;
}
}
if( nElem>0 ){
int nByte = sizeof(Fts3SegReader) + (nElem+1)*sizeof(Fts3HashElem *);
pReader = (Fts3SegReader *)sqlite3_malloc(nByte);
if( !pReader ){
rc = SQLITE_NOMEM;
}else{
memset(pReader, 0, nByte);
pReader->iIdx = 0x7FFFFFFF;
pReader->ppNextElem = (Fts3HashElem **)&pReader[1];
memcpy(pReader->ppNextElem, aElem, nElem*sizeof(Fts3HashElem *));
}
}
if( bPrefix ){
sqlite3_free(aElem);
}
*ppReader = pReader;
return rc;
}
/*
** Compare the entries pointed to by two Fts3SegReader structures.
** Comparison is as follows:
**
** 1) EOF is greater than not EOF.
**
** 2) The current terms (if any) are compared using memcmp(). If one
** term is a prefix of another, the longer term is considered the
** larger.
**
** 3) By segment age. An older segment is considered larger.
*/
static int fts3SegReaderCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
int rc;
if( pLhs->aNode && pRhs->aNode ){
int rc2 = pLhs->nTerm - pRhs->nTerm;
if( rc2<0 ){
rc = memcmp(pLhs->zTerm, pRhs->zTerm, pLhs->nTerm);
}else{
rc = memcmp(pLhs->zTerm, pRhs->zTerm, pRhs->nTerm);
}
if( rc==0 ){
rc = rc2;
}
}else{
rc = (pLhs->aNode==0) - (pRhs->aNode==0);
}
if( rc==0 ){
rc = pRhs->iIdx - pLhs->iIdx;
}
assert( rc!=0 );
return rc;
}
/*
** A different comparison function for SegReader structures. In this
** version, it is assumed that each SegReader points to an entry in
** a doclist for identical terms. Comparison is made as follows:
**
** 1) EOF (end of doclist in this case) is greater than not EOF.
**
** 2) By current docid.
**
** 3) By segment age. An older segment is considered larger.
*/
static int fts3SegReaderDoclistCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
if( rc==0 ){
if( pLhs->iDocid==pRhs->iDocid ){
rc = pRhs->iIdx - pLhs->iIdx;
}else{
rc = (pLhs->iDocid > pRhs->iDocid) ? 1 : -1;
}
}
assert( pLhs->aNode && pRhs->aNode );
return rc;
}
static int fts3SegReaderDoclistCmpRev(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
if( rc==0 ){
if( pLhs->iDocid==pRhs->iDocid ){
rc = pRhs->iIdx - pLhs->iIdx;
}else{
rc = (pLhs->iDocid < pRhs->iDocid) ? 1 : -1;
}
}
assert( pLhs->aNode && pRhs->aNode );
return rc;
}
/*
** Compare the term that the Fts3SegReader object passed as the first argument
** points to with the term specified by arguments zTerm and nTerm.
**
** If the pSeg iterator is already at EOF, return 0. Otherwise, return
** -ve if the pSeg term is less than zTerm/nTerm, 0 if the two terms are
** equal, or +ve if the pSeg term is greater than zTerm/nTerm.
*/
static int fts3SegReaderTermCmp(
Fts3SegReader *pSeg, /* Segment reader object */
const char *zTerm, /* Term to compare to */
int nTerm /* Size of term zTerm in bytes */
){
int res = 0;
if( pSeg->aNode ){
if( pSeg->nTerm>nTerm ){
res = memcmp(pSeg->zTerm, zTerm, nTerm);
}else{
res = memcmp(pSeg->zTerm, zTerm, pSeg->nTerm);
}
if( res==0 ){
res = pSeg->nTerm-nTerm;
}
}
return res;
}
/*
** Argument apSegment is an array of nSegment elements. It is known that
** the final (nSegment-nSuspect) members are already in sorted order
** (according to the comparison function provided). This function shuffles
** the array around until all entries are in sorted order.
*/
static void fts3SegReaderSort(
Fts3SegReader **apSegment, /* Array to sort entries of */
int nSegment, /* Size of apSegment array */
int nSuspect, /* Unsorted entry count */
int (*xCmp)(Fts3SegReader *, Fts3SegReader *) /* Comparison function */
){
int i; /* Iterator variable */
assert( nSuspect<=nSegment );
if( nSuspect==nSegment ) nSuspect--;
for(i=nSuspect-1; i>=0; i--){
int j;
for(j=i; j<(nSegment-1); j++){
Fts3SegReader *pTmp;
if( xCmp(apSegment[j], apSegment[j+1])<0 ) break;
pTmp = apSegment[j+1];
apSegment[j+1] = apSegment[j];
apSegment[j] = pTmp;
}
}
#ifndef NDEBUG
/* Check that the list really is sorted now. */
for(i=0; i<(nSuspect-1); i++){
assert( xCmp(apSegment[i], apSegment[i+1])<0 );
}
#endif
}
/*
** Insert a record into the %_segments table.
*/
static int fts3WriteSegment(
Fts3Table *p, /* Virtual table handle */
sqlite3_int64 iBlock, /* Block id for new block */
char *z, /* Pointer to buffer containing block data */
int n /* Size of buffer z in bytes */
){
sqlite3_stmt *pStmt;
int rc = fts3SqlStmt(p, SQL_INSERT_SEGMENTS, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pStmt, 1, iBlock);
sqlite3_bind_blob(pStmt, 2, z, n, SQLITE_STATIC);
sqlite3_step(pStmt);
rc = sqlite3_reset(pStmt);
}
return rc;
}
/*
** Find the largest relative level number in the table. If successful, set
** *pnMax to this value and return SQLITE_OK. Otherwise, if an error occurs,
** set *pnMax to zero and return an SQLite error code.
*/
int sqlite3Fts3MaxLevel(Fts3Table *p, int *pnMax){
int rc;
int mxLevel = 0;
sqlite3_stmt *pStmt = 0;
rc = fts3SqlStmt(p, SQL_SELECT_MXLEVEL, &pStmt, 0);
if( rc==SQLITE_OK ){
if( SQLITE_ROW==sqlite3_step(pStmt) ){
mxLevel = sqlite3_column_int(pStmt, 0);
}
rc = sqlite3_reset(pStmt);
}
*pnMax = mxLevel;
return rc;
}
/*
** Insert a record into the %_segdir table.
*/
static int fts3WriteSegdir(
Fts3Table *p, /* Virtual table handle */
sqlite3_int64 iLevel, /* Value for "level" field (absolute level) */
int iIdx, /* Value for "idx" field */
sqlite3_int64 iStartBlock, /* Value for "start_block" field */
sqlite3_int64 iLeafEndBlock, /* Value for "leaves_end_block" field */
sqlite3_int64 iEndBlock, /* Value for "end_block" field */
sqlite3_int64 nLeafData, /* Bytes of leaf data in segment */
char *zRoot, /* Blob value for "root" field */
int nRoot /* Number of bytes in buffer zRoot */
){
sqlite3_stmt *pStmt;
int rc = fts3SqlStmt(p, SQL_INSERT_SEGDIR, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pStmt, 1, iLevel);
sqlite3_bind_int(pStmt, 2, iIdx);
sqlite3_bind_int64(pStmt, 3, iStartBlock);
sqlite3_bind_int64(pStmt, 4, iLeafEndBlock);
if( nLeafData==0 ){
sqlite3_bind_int64(pStmt, 5, iEndBlock);
}else{
char *zEnd = sqlite3_mprintf("%lld %lld", iEndBlock, nLeafData);
if( !zEnd ) return SQLITE_NOMEM;
sqlite3_bind_text(pStmt, 5, zEnd, -1, sqlite3_free);
}
sqlite3_bind_blob(pStmt, 6, zRoot, nRoot, SQLITE_STATIC);
sqlite3_step(pStmt);
rc = sqlite3_reset(pStmt);
}
return rc;
}
/*
** Return the size of the common prefix (if any) shared by zPrev and
** zNext, in bytes. For example,
**
** fts3PrefixCompress("abc", 3, "abcdef", 6) // returns 3
** fts3PrefixCompress("abX", 3, "abcdef", 6) // returns 2
** fts3PrefixCompress("abX", 3, "Xbcdef", 6) // returns 0
*/
static int fts3PrefixCompress(
const char *zPrev, /* Buffer containing previous term */
int nPrev, /* Size of buffer zPrev in bytes */
const char *zNext, /* Buffer containing next term */
int nNext /* Size of buffer zNext in bytes */
){
int n;
UNUSED_PARAMETER(nNext);
for(n=0; n<nPrev && zPrev[n]==zNext[n]; n++);
return n;
}
/*
** Add term zTerm to the SegmentNode. It is guaranteed that zTerm is larger
** (according to memcmp) than the previous term.
*/
static int fts3NodeAddTerm(
Fts3Table *p, /* Virtual table handle */
SegmentNode **ppTree, /* IN/OUT: SegmentNode handle */
int isCopyTerm, /* True if zTerm/nTerm is transient */
const char *zTerm, /* Pointer to buffer containing term */
int nTerm /* Size of term in bytes */
){
SegmentNode *pTree = *ppTree;
int rc;
SegmentNode *pNew;
/* First try to append the term to the current node. Return early if
** this is possible.
*/
if( pTree ){
int nData = pTree->nData; /* Current size of node in bytes */
int nReq = nData; /* Required space after adding zTerm */
int nPrefix; /* Number of bytes of prefix compression */
int nSuffix; /* Suffix length */
nPrefix = fts3PrefixCompress(pTree->zTerm, pTree->nTerm, zTerm, nTerm);
nSuffix = nTerm-nPrefix;
nReq += sqlite3Fts3VarintLen(nPrefix)+sqlite3Fts3VarintLen(nSuffix)+nSuffix;
if( nReq<=p->nNodeSize || !pTree->zTerm ){
if( nReq>p->nNodeSize ){
/* An unusual case: this is the first term to be added to the node
** and the static node buffer (p->nNodeSize bytes) is not large
** enough. Use a separately malloced buffer instead This wastes
** p->nNodeSize bytes, but since this scenario only comes about when
** the database contain two terms that share a prefix of almost 2KB,
** this is not expected to be a serious problem.
*/
assert( pTree->aData==(char *)&pTree[1] );
pTree->aData = (char *)sqlite3_malloc(nReq);
if( !pTree->aData ){
return SQLITE_NOMEM;
}
}
if( pTree->zTerm ){
/* There is no prefix-length field for first term in a node */
nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nPrefix);
}
nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nSuffix);
memcpy(&pTree->aData[nData], &zTerm[nPrefix], nSuffix);
pTree->nData = nData + nSuffix;
pTree->nEntry++;
if( isCopyTerm ){
if( pTree->nMalloc<nTerm ){
char *zNew = sqlite3_realloc(pTree->zMalloc, nTerm*2);
if( !zNew ){
return SQLITE_NOMEM;
}
pTree->nMalloc = nTerm*2;
pTree->zMalloc = zNew;
}
pTree->zTerm = pTree->zMalloc;
memcpy(pTree->zTerm, zTerm, nTerm);
pTree->nTerm = nTerm;
}else{
pTree->zTerm = (char *)zTerm;
pTree->nTerm = nTerm;
}
return SQLITE_OK;
}
}
/* If control flows to here, it was not possible to append zTerm to the
** current node. Create a new node (a right-sibling of the current node).
** If this is the first node in the tree, the term is added to it.
**
** Otherwise, the term is not added to the new node, it is left empty for
** now. Instead, the term is inserted into the parent of pTree. If pTree
** has no parent, one is created here.
*/
pNew = (SegmentNode *)sqlite3_malloc(sizeof(SegmentNode) + p->nNodeSize);
if( !pNew ){
return SQLITE_NOMEM;
}
memset(pNew, 0, sizeof(SegmentNode));
pNew->nData = 1 + FTS3_VARINT_MAX;
pNew->aData = (char *)&pNew[1];
if( pTree ){
SegmentNode *pParent = pTree->pParent;
rc = fts3NodeAddTerm(p, &pParent, isCopyTerm, zTerm, nTerm);
if( pTree->pParent==0 ){
pTree->pParent = pParent;
}
pTree->pRight = pNew;
pNew->pLeftmost = pTree->pLeftmost;
pNew->pParent = pParent;
pNew->zMalloc = pTree->zMalloc;
pNew->nMalloc = pTree->nMalloc;
pTree->zMalloc = 0;
}else{
pNew->pLeftmost = pNew;
rc = fts3NodeAddTerm(p, &pNew, isCopyTerm, zTerm, nTerm);
}
*ppTree = pNew;
return rc;
}
/*
** Helper function for fts3NodeWrite().
*/
static int fts3TreeFinishNode(
SegmentNode *pTree,
int iHeight,
sqlite3_int64 iLeftChild
){
int nStart;
assert( iHeight>=1 && iHeight<128 );
nStart = FTS3_VARINT_MAX - sqlite3Fts3VarintLen(iLeftChild);
pTree->aData[nStart] = (char)iHeight;
sqlite3Fts3PutVarint(&pTree->aData[nStart+1], iLeftChild);
return nStart;
}
/*
** Write the buffer for the segment node pTree and all of its peers to the
** database. Then call this function recursively to write the parent of
** pTree and its peers to the database.
**
** Except, if pTree is a root node, do not write it to the database. Instead,
** set output variables *paRoot and *pnRoot to contain the root node.
**
** If successful, SQLITE_OK is returned and output variable *piLast is
** set to the largest blockid written to the database (or zero if no
** blocks were written to the db). Otherwise, an SQLite error code is
** returned.
*/
static int fts3NodeWrite(
Fts3Table *p, /* Virtual table handle */
SegmentNode *pTree, /* SegmentNode handle */
int iHeight, /* Height of this node in tree */
sqlite3_int64 iLeaf, /* Block id of first leaf node */
sqlite3_int64 iFree, /* Block id of next free slot in %_segments */
sqlite3_int64 *piLast, /* OUT: Block id of last entry written */
char **paRoot, /* OUT: Data for root node */
int *pnRoot /* OUT: Size of root node in bytes */
){
int rc = SQLITE_OK;
if( !pTree->pParent ){
/* Root node of the tree. */
int nStart = fts3TreeFinishNode(pTree, iHeight, iLeaf);
*piLast = iFree-1;
*pnRoot = pTree->nData - nStart;
*paRoot = &pTree->aData[nStart];
}else{
SegmentNode *pIter;
sqlite3_int64 iNextFree = iFree;
sqlite3_int64 iNextLeaf = iLeaf;
for(pIter=pTree->pLeftmost; pIter && rc==SQLITE_OK; pIter=pIter->pRight){
int nStart = fts3TreeFinishNode(pIter, iHeight, iNextLeaf);
int nWrite = pIter->nData - nStart;
rc = fts3WriteSegment(p, iNextFree, &pIter->aData[nStart], nWrite);
iNextFree++;
iNextLeaf += (pIter->nEntry+1);
}
if( rc==SQLITE_OK ){
assert( iNextLeaf==iFree );
rc = fts3NodeWrite(
p, pTree->pParent, iHeight+1, iFree, iNextFree, piLast, paRoot, pnRoot
);
}
}
return rc;
}
/*
** Free all memory allocations associated with the tree pTree.
*/
static void fts3NodeFree(SegmentNode *pTree){
if( pTree ){
SegmentNode *p = pTree->pLeftmost;
fts3NodeFree(p->pParent);
while( p ){
SegmentNode *pRight = p->pRight;
if( p->aData!=(char *)&p[1] ){
sqlite3_free(p->aData);
}
assert( pRight==0 || p->zMalloc==0 );
sqlite3_free(p->zMalloc);
sqlite3_free(p);
p = pRight;
}
}
}
/*
** Add a term to the segment being constructed by the SegmentWriter object
** *ppWriter. When adding the first term to a segment, *ppWriter should
** be passed NULL. This function will allocate a new SegmentWriter object
** and return it via the input/output variable *ppWriter in this case.
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
*/
static int fts3SegWriterAdd(
Fts3Table *p, /* Virtual table handle */
SegmentWriter **ppWriter, /* IN/OUT: SegmentWriter handle */
int isCopyTerm, /* True if buffer zTerm must be copied */
const char *zTerm, /* Pointer to buffer containing term */
int nTerm, /* Size of term in bytes */
const char *aDoclist, /* Pointer to buffer containing doclist */
int nDoclist /* Size of doclist in bytes */
){
int nPrefix; /* Size of term prefix in bytes */
int nSuffix; /* Size of term suffix in bytes */
int nReq; /* Number of bytes required on leaf page */
int nData;
SegmentWriter *pWriter = *ppWriter;
if( !pWriter ){
int rc;
sqlite3_stmt *pStmt;
/* Allocate the SegmentWriter structure */
pWriter = (SegmentWriter *)sqlite3_malloc(sizeof(SegmentWriter));
if( !pWriter ) return SQLITE_NOMEM;
memset(pWriter, 0, sizeof(SegmentWriter));
*ppWriter = pWriter;
/* Allocate a buffer in which to accumulate data */
pWriter->aData = (char *)sqlite3_malloc(p->nNodeSize);
if( !pWriter->aData ) return SQLITE_NOMEM;
pWriter->nSize = p->nNodeSize;
/* Find the next free blockid in the %_segments table */
rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pStmt, 0);
if( rc!=SQLITE_OK ) return rc;
if( SQLITE_ROW==sqlite3_step(pStmt) ){
pWriter->iFree = sqlite3_column_int64(pStmt, 0);
pWriter->iFirst = pWriter->iFree;
}
rc = sqlite3_reset(pStmt);
if( rc!=SQLITE_OK ) return rc;
}
nData = pWriter->nData;
nPrefix = fts3PrefixCompress(pWriter->zTerm, pWriter->nTerm, zTerm, nTerm);
nSuffix = nTerm-nPrefix;
/* Figure out how many bytes are required by this new entry */
nReq = sqlite3Fts3VarintLen(nPrefix) + /* varint containing prefix size */
sqlite3Fts3VarintLen(nSuffix) + /* varint containing suffix size */
nSuffix + /* Term suffix */
sqlite3Fts3VarintLen(nDoclist) + /* Size of doclist */
nDoclist; /* Doclist data */
if( nData>0 && nData+nReq>p->nNodeSize ){
int rc;
/* The current leaf node is full. Write it out to the database. */
rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, nData);
if( rc!=SQLITE_OK ) return rc;
p->nLeafAdd++;
/* Add the current term to the interior node tree. The term added to
** the interior tree must:
**
** a) be greater than the largest term on the leaf node just written
** to the database (still available in pWriter->zTerm), and
**
** b) be less than or equal to the term about to be added to the new
** leaf node (zTerm/nTerm).
**
** In other words, it must be the prefix of zTerm 1 byte longer than
** the common prefix (if any) of zTerm and pWriter->zTerm.
*/
assert( nPrefix<nTerm );
rc = fts3NodeAddTerm(p, &pWriter->pTree, isCopyTerm, zTerm, nPrefix+1);
if( rc!=SQLITE_OK ) return rc;
nData = 0;
pWriter->nTerm = 0;
nPrefix = 0;
nSuffix = nTerm;
nReq = 1 + /* varint containing prefix size */
sqlite3Fts3VarintLen(nTerm) + /* varint containing suffix size */
nTerm + /* Term suffix */
sqlite3Fts3VarintLen(nDoclist) + /* Size of doclist */
nDoclist; /* Doclist data */
}
/* Increase the total number of bytes written to account for the new entry. */
pWriter->nLeafData += nReq;
/* If the buffer currently allocated is too small for this entry, realloc
** the buffer to make it large enough.
*/
if( nReq>pWriter->nSize ){
char *aNew = sqlite3_realloc(pWriter->aData, nReq);
if( !aNew ) return SQLITE_NOMEM;
pWriter->aData = aNew;
pWriter->nSize = nReq;
}
assert( nData+nReq<=pWriter->nSize );
/* Append the prefix-compressed term and doclist to the buffer. */
nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nPrefix);
nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nSuffix);
memcpy(&pWriter->aData[nData], &zTerm[nPrefix], nSuffix);
nData += nSuffix;
nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nDoclist);
memcpy(&pWriter->aData[nData], aDoclist, nDoclist);
pWriter->nData = nData + nDoclist;
/* Save the current term so that it can be used to prefix-compress the next.
** If the isCopyTerm parameter is true, then the buffer pointed to by
** zTerm is transient, so take a copy of the term data. Otherwise, just
** store a copy of the pointer.
*/
if( isCopyTerm ){
if( nTerm>pWriter->nMalloc ){
char *zNew = sqlite3_realloc(pWriter->zMalloc, nTerm*2);
if( !zNew ){
return SQLITE_NOMEM;
}
pWriter->nMalloc = nTerm*2;
pWriter->zMalloc = zNew;
pWriter->zTerm = zNew;
}
assert( pWriter->zTerm==pWriter->zMalloc );
memcpy(pWriter->zTerm, zTerm, nTerm);
}else{
pWriter->zTerm = (char *)zTerm;
}
pWriter->nTerm = nTerm;
return SQLITE_OK;
}
/*
** Flush all data associated with the SegmentWriter object pWriter to the
** database. This function must be called after all terms have been added
** to the segment using fts3SegWriterAdd(). If successful, SQLITE_OK is
** returned. Otherwise, an SQLite error code.
*/
static int fts3SegWriterFlush(
Fts3Table *p, /* Virtual table handle */
SegmentWriter *pWriter, /* SegmentWriter to flush to the db */
sqlite3_int64 iLevel, /* Value for 'level' column of %_segdir */
int iIdx /* Value for 'idx' column of %_segdir */
){
int rc; /* Return code */
if( pWriter->pTree ){
sqlite3_int64 iLast = 0; /* Largest block id written to database */
sqlite3_int64 iLastLeaf; /* Largest leaf block id written to db */
char *zRoot = NULL; /* Pointer to buffer containing root node */
int nRoot = 0; /* Size of buffer zRoot */
iLastLeaf = pWriter->iFree;
rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, pWriter->nData);
if( rc==SQLITE_OK ){
rc = fts3NodeWrite(p, pWriter->pTree, 1,
pWriter->iFirst, pWriter->iFree, &iLast, &zRoot, &nRoot);
}
if( rc==SQLITE_OK ){
rc = fts3WriteSegdir(p, iLevel, iIdx,
pWriter->iFirst, iLastLeaf, iLast, pWriter->nLeafData, zRoot, nRoot);
}
}else{
/* The entire tree fits on the root node. Write it to the segdir table. */
rc = fts3WriteSegdir(p, iLevel, iIdx,
0, 0, 0, pWriter->nLeafData, pWriter->aData, pWriter->nData);
}
p->nLeafAdd++;
return rc;
}
/*
** Release all memory held by the SegmentWriter object passed as the
** first argument.
*/
static void fts3SegWriterFree(SegmentWriter *pWriter){
if( pWriter ){
sqlite3_free(pWriter->aData);
sqlite3_free(pWriter->zMalloc);
fts3NodeFree(pWriter->pTree);
sqlite3_free(pWriter);
}
}
/*
** The first value in the apVal[] array is assumed to contain an integer.
** This function tests if there exist any documents with docid values that
** are different from that integer. i.e. if deleting the document with docid
** pRowid would mean the FTS3 table were empty.
**
** If successful, *pisEmpty is set to true if the table is empty except for
** document pRowid, or false otherwise, and SQLITE_OK is returned. If an
** error occurs, an SQLite error code is returned.
*/
static int fts3IsEmpty(Fts3Table *p, sqlite3_value *pRowid, int *pisEmpty){
sqlite3_stmt *pStmt;
int rc;
if( p->zContentTbl ){
/* If using the content=xxx option, assume the table is never empty */
*pisEmpty = 0;
rc = SQLITE_OK;
}else{
rc = fts3SqlStmt(p, SQL_IS_EMPTY, &pStmt, &pRowid);
if( rc==SQLITE_OK ){
if( SQLITE_ROW==sqlite3_step(pStmt) ){
*pisEmpty = sqlite3_column_int(pStmt, 0);
}
rc = sqlite3_reset(pStmt);
}
}
return rc;
}
/*
** Set *pnMax to the largest segment level in the database for the index
** iIndex.
**
** Segment levels are stored in the 'level' column of the %_segdir table.
**
** Return SQLITE_OK if successful, or an SQLite error code if not.
*/
static int fts3SegmentMaxLevel(
Fts3Table *p,
int iLangid,
int iIndex,
sqlite3_int64 *pnMax
){
sqlite3_stmt *pStmt;
int rc;
assert( iIndex>=0 && iIndex<p->nIndex );
/* Set pStmt to the compiled version of:
**
** SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
**
** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
*/
rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
if( rc!=SQLITE_OK ) return rc;
sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
sqlite3_bind_int64(pStmt, 2,
getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
);
if( SQLITE_ROW==sqlite3_step(pStmt) ){
*pnMax = sqlite3_column_int64(pStmt, 0);
}
return sqlite3_reset(pStmt);
}
/*
** iAbsLevel is an absolute level that may be assumed to exist within
** the database. This function checks if it is the largest level number
** within its index. Assuming no error occurs, *pbMax is set to 1 if
** iAbsLevel is indeed the largest level, or 0 otherwise, and SQLITE_OK
** is returned. If an error occurs, an error code is returned and the
** final value of *pbMax is undefined.
*/
static int fts3SegmentIsMaxLevel(Fts3Table *p, i64 iAbsLevel, int *pbMax){
/* Set pStmt to the compiled version of:
**
** SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
**
** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
*/
sqlite3_stmt *pStmt;
int rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
if( rc!=SQLITE_OK ) return rc;
sqlite3_bind_int64(pStmt, 1, iAbsLevel+1);
sqlite3_bind_int64(pStmt, 2,
((iAbsLevel/FTS3_SEGDIR_MAXLEVEL)+1) * FTS3_SEGDIR_MAXLEVEL
);
*pbMax = 0;
if( SQLITE_ROW==sqlite3_step(pStmt) ){
*pbMax = sqlite3_column_type(pStmt, 0)==SQLITE_NULL;
}
return sqlite3_reset(pStmt);
}
/*
** Delete all entries in the %_segments table associated with the segment
** opened with seg-reader pSeg. This function does not affect the contents
** of the %_segdir table.
*/
static int fts3DeleteSegment(
Fts3Table *p, /* FTS table handle */
Fts3SegReader *pSeg /* Segment to delete */
){
int rc = SQLITE_OK; /* Return code */
if( pSeg->iStartBlock ){
sqlite3_stmt *pDelete; /* SQL statement to delete rows */
rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDelete, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pDelete, 1, pSeg->iStartBlock);
sqlite3_bind_int64(pDelete, 2, pSeg->iEndBlock);
sqlite3_step(pDelete);
rc = sqlite3_reset(pDelete);
}
}
return rc;
}
/*
** This function is used after merging multiple segments into a single large
** segment to delete the old, now redundant, segment b-trees. Specifically,
** it:
**
** 1) Deletes all %_segments entries for the segments associated with
** each of the SegReader objects in the array passed as the third
** argument, and
**
** 2) deletes all %_segdir entries with level iLevel, or all %_segdir
** entries regardless of level if (iLevel<0).
**
** SQLITE_OK is returned if successful, otherwise an SQLite error code.
*/
static int fts3DeleteSegdir(
Fts3Table *p, /* Virtual table handle */
int iLangid, /* Language id */
int iIndex, /* Index for p->aIndex */
int iLevel, /* Level of %_segdir entries to delete */
Fts3SegReader **apSegment, /* Array of SegReader objects */
int nReader /* Size of array apSegment */
){
int rc = SQLITE_OK; /* Return Code */
int i; /* Iterator variable */
sqlite3_stmt *pDelete = 0; /* SQL statement to delete rows */
for(i=0; rc==SQLITE_OK && i<nReader; i++){
rc = fts3DeleteSegment(p, apSegment[i]);
}
if( rc!=SQLITE_OK ){
return rc;
}
assert( iLevel>=0 || iLevel==FTS3_SEGCURSOR_ALL );
if( iLevel==FTS3_SEGCURSOR_ALL ){
rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_RANGE, &pDelete, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
sqlite3_bind_int64(pDelete, 2,
getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
);
}
}else{
rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pDelete, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(
pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
);
}
}
if( rc==SQLITE_OK ){
sqlite3_step(pDelete);
rc = sqlite3_reset(pDelete);
}
return rc;
}
/*
** When this function is called, buffer *ppList (size *pnList bytes) contains
** a position list that may (or may not) feature multiple columns. This
** function adjusts the pointer *ppList and the length *pnList so that they
** identify the subset of the position list that corresponds to column iCol.
**
** If there are no entries in the input position list for column iCol, then
** *pnList is set to zero before returning.
**
** If parameter bZero is non-zero, then any part of the input list following
** the end of the output list is zeroed before returning.
*/
static void fts3ColumnFilter(
int iCol, /* Column to filter on */
int bZero, /* Zero out anything following *ppList */
char **ppList, /* IN/OUT: Pointer to position list */
int *pnList /* IN/OUT: Size of buffer *ppList in bytes */
){
char *pList = *ppList;
int nList = *pnList;
char *pEnd = &pList[nList];
int iCurrent = 0;
char *p = pList;
assert( iCol>=0 );
while( 1 ){
char c = 0;
while( p<pEnd && (c | *p)&0xFE ) c = *p++ & 0x80;
if( iCol==iCurrent ){
nList = (int)(p - pList);
break;
}
nList -= (int)(p - pList);
pList = p;
if( nList==0 ){
break;
}
p = &pList[1];
p += fts3GetVarint32(p, &iCurrent);
}
if( bZero && &pList[nList]!=pEnd ){
memset(&pList[nList], 0, pEnd - &pList[nList]);
}
*ppList = pList;
*pnList = nList;
}
/*
** Cache data in the Fts3MultiSegReader.aBuffer[] buffer (overwriting any
** existing data). Grow the buffer if required.
**
** If successful, return SQLITE_OK. Otherwise, if an OOM error is encountered
** trying to resize the buffer, return SQLITE_NOMEM.
*/
static int fts3MsrBufferData(
Fts3MultiSegReader *pMsr, /* Multi-segment-reader handle */
char *pList,
int nList
){
if( nList>pMsr->nBuffer ){
char *pNew;
pMsr->nBuffer = nList*2;
pNew = (char *)sqlite3_realloc(pMsr->aBuffer, pMsr->nBuffer);
if( !pNew ) return SQLITE_NOMEM;
pMsr->aBuffer = pNew;
}
memcpy(pMsr->aBuffer, pList, nList);
return SQLITE_OK;
}
int sqlite3Fts3MsrIncrNext(
Fts3Table *p, /* Virtual table handle */
Fts3MultiSegReader *pMsr, /* Multi-segment-reader handle */
sqlite3_int64 *piDocid, /* OUT: Docid value */
char **paPoslist, /* OUT: Pointer to position list */
int *pnPoslist /* OUT: Size of position list in bytes */
){
int nMerge = pMsr->nAdvance;
Fts3SegReader **apSegment = pMsr->apSegment;
int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
);
if( nMerge==0 ){
*paPoslist = 0;
return SQLITE_OK;
}
while( 1 ){
Fts3SegReader *pSeg;
pSeg = pMsr->apSegment[0];
if( pSeg->pOffsetList==0 ){
*paPoslist = 0;
break;
}else{
int rc;
char *pList;
int nList;
int j;
sqlite3_int64 iDocid = apSegment[0]->iDocid;
rc = fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
j = 1;
while( rc==SQLITE_OK
&& j<nMerge
&& apSegment[j]->pOffsetList
&& apSegment[j]->iDocid==iDocid
){
rc = fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
j++;
}
if( rc!=SQLITE_OK ) return rc;
fts3SegReaderSort(pMsr->apSegment, nMerge, j, xCmp);
if( nList>0 && fts3SegReaderIsPending(apSegment[0]) ){
rc = fts3MsrBufferData(pMsr, pList, nList+1);
if( rc!=SQLITE_OK ) return rc;
assert( (pMsr->aBuffer[nList] & 0xFE)==0x00 );
pList = pMsr->aBuffer;
}
if( pMsr->iColFilter>=0 ){
fts3ColumnFilter(pMsr->iColFilter, 1, &pList, &nList);
}
if( nList>0 ){
*paPoslist = pList;
*piDocid = iDocid;
*pnPoslist = nList;
break;
}
}
}
return SQLITE_OK;
}
static int fts3SegReaderStart(
Fts3Table *p, /* Virtual table handle */
Fts3MultiSegReader *pCsr, /* Cursor object */
const char *zTerm, /* Term searched for (or NULL) */
int nTerm /* Length of zTerm in bytes */
){
int i;
int nSeg = pCsr->nSegment;
/* If the Fts3SegFilter defines a specific term (or term prefix) to search
** for, then advance each segment iterator until it points to a term of
** equal or greater value than the specified term. This prevents many
** unnecessary merge/sort operations for the case where single segment
** b-tree leaf nodes contain more than one term.
*/
for(i=0; pCsr->bRestart==0 && i<pCsr->nSegment; i++){
int res = 0;
Fts3SegReader *pSeg = pCsr->apSegment[i];
do {
int rc = fts3SegReaderNext(p, pSeg, 0);
if( rc!=SQLITE_OK ) return rc;
}while( zTerm && (res = fts3SegReaderTermCmp(pSeg, zTerm, nTerm))<0 );
if( pSeg->bLookup && res!=0 ){
fts3SegReaderSetEof(pSeg);
}
}
fts3SegReaderSort(pCsr->apSegment, nSeg, nSeg, fts3SegReaderCmp);
return SQLITE_OK;
}
int sqlite3Fts3SegReaderStart(
Fts3Table *p, /* Virtual table handle */
Fts3MultiSegReader *pCsr, /* Cursor object */
Fts3SegFilter *pFilter /* Restrictions on range of iteration */
){
pCsr->pFilter = pFilter;
return fts3SegReaderStart(p, pCsr, pFilter->zTerm, pFilter->nTerm);
}
int sqlite3Fts3MsrIncrStart(
Fts3Table *p, /* Virtual table handle */
Fts3MultiSegReader *pCsr, /* Cursor object */
int iCol, /* Column to match on. */
const char *zTerm, /* Term to iterate through a doclist for */
int nTerm /* Number of bytes in zTerm */
){
int i;
int rc;
int nSegment = pCsr->nSegment;
int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
);
assert( pCsr->pFilter==0 );
assert( zTerm && nTerm>0 );
/* Advance each segment iterator until it points to the term zTerm/nTerm. */
rc = fts3SegReaderStart(p, pCsr, zTerm, nTerm);
if( rc!=SQLITE_OK ) return rc;
/* Determine how many of the segments actually point to zTerm/nTerm. */
for(i=0; i<nSegment; i++){
Fts3SegReader *pSeg = pCsr->apSegment[i];
if( !pSeg->aNode || fts3SegReaderTermCmp(pSeg, zTerm, nTerm) ){
break;
}
}
pCsr->nAdvance = i;
/* Advance each of the segments to point to the first docid. */
for(i=0; i<pCsr->nAdvance; i++){
rc = fts3SegReaderFirstDocid(p, pCsr->apSegment[i]);
if( rc!=SQLITE_OK ) return rc;
}
fts3SegReaderSort(pCsr->apSegment, i, i, xCmp);
assert( iCol<0 || iCol<p->nColumn );
pCsr->iColFilter = iCol;
return SQLITE_OK;
}
/*
** This function is called on a MultiSegReader that has been started using
** sqlite3Fts3MsrIncrStart(). One or more calls to MsrIncrNext() may also
** have been made. Calling this function puts the MultiSegReader in such
** a state that if the next two calls are:
**
** sqlite3Fts3SegReaderStart()
** sqlite3Fts3SegReaderStep()
**
** then the entire doclist for the term is available in
** MultiSegReader.aDoclist/nDoclist.
*/
int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr){
int i; /* Used to iterate through segment-readers */
assert( pCsr->zTerm==0 );
assert( pCsr->nTerm==0 );
assert( pCsr->aDoclist==0 );
assert( pCsr->nDoclist==0 );
pCsr->nAdvance = 0;
pCsr->bRestart = 1;
for(i=0; i<pCsr->nSegment; i++){
pCsr->apSegment[i]->pOffsetList = 0;
pCsr->apSegment[i]->nOffsetList = 0;
pCsr->apSegment[i]->iDocid = 0;
}
return SQLITE_OK;
}
int sqlite3Fts3SegReaderStep(
Fts3Table *p, /* Virtual table handle */
Fts3MultiSegReader *pCsr /* Cursor object */
){
int rc = SQLITE_OK;
int isIgnoreEmpty = (pCsr->pFilter->flags & FTS3_SEGMENT_IGNORE_EMPTY);
int isRequirePos = (pCsr->pFilter->flags & FTS3_SEGMENT_REQUIRE_POS);
int isColFilter = (pCsr->pFilter->flags & FTS3_SEGMENT_COLUMN_FILTER);
int isPrefix = (pCsr->pFilter->flags & FTS3_SEGMENT_PREFIX);
int isScan = (pCsr->pFilter->flags & FTS3_SEGMENT_SCAN);
int isFirst = (pCsr->pFilter->flags & FTS3_SEGMENT_FIRST);
Fts3SegReader **apSegment = pCsr->apSegment;
int nSegment = pCsr->nSegment;
Fts3SegFilter *pFilter = pCsr->pFilter;
int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
);
if( pCsr->nSegment==0 ) return SQLITE_OK;
do {
int nMerge;
int i;
/* Advance the first pCsr->nAdvance entries in the apSegment[] array
** forward. Then sort the list in order of current term again.
*/
for(i=0; i<pCsr->nAdvance; i++){
Fts3SegReader *pSeg = apSegment[i];
if( pSeg->bLookup ){
fts3SegReaderSetEof(pSeg);
}else{
rc = fts3SegReaderNext(p, pSeg, 0);
}
if( rc!=SQLITE_OK ) return rc;
}
fts3SegReaderSort(apSegment, nSegment, pCsr->nAdvance, fts3SegReaderCmp);
pCsr->nAdvance = 0;
/* If all the seg-readers are at EOF, we're finished. return SQLITE_OK. */
assert( rc==SQLITE_OK );
if( apSegment[0]->aNode==0 ) break;
pCsr->nTerm = apSegment[0]->nTerm;
pCsr->zTerm = apSegment[0]->zTerm;
/* If this is a prefix-search, and if the term that apSegment[0] points
** to does not share a suffix with pFilter->zTerm/nTerm, then all
** required callbacks have been made. In this case exit early.
**
** Similarly, if this is a search for an exact match, and the first term
** of segment apSegment[0] is not a match, exit early.
*/
if( pFilter->zTerm && !isScan ){
if( pCsr->nTerm<pFilter->nTerm
|| (!isPrefix && pCsr->nTerm>pFilter->nTerm)
|| memcmp(pCsr->zTerm, pFilter->zTerm, pFilter->nTerm)
){
break;
}
}
nMerge = 1;
while( nMerge<nSegment
&& apSegment[nMerge]->aNode
&& apSegment[nMerge]->nTerm==pCsr->nTerm
&& 0==memcmp(pCsr->zTerm, apSegment[nMerge]->zTerm, pCsr->nTerm)
){
nMerge++;
}
assert( isIgnoreEmpty || (isRequirePos && !isColFilter) );
if( nMerge==1
&& !isIgnoreEmpty
&& !isFirst
&& (p->bDescIdx==0 || fts3SegReaderIsPending(apSegment[0])==0)
){
pCsr->nDoclist = apSegment[0]->nDoclist;
if( fts3SegReaderIsPending(apSegment[0]) ){
rc = fts3MsrBufferData(pCsr, apSegment[0]->aDoclist, pCsr->nDoclist);
pCsr->aDoclist = pCsr->aBuffer;
}else{
pCsr->aDoclist = apSegment[0]->aDoclist;
}
if( rc==SQLITE_OK ) rc = SQLITE_ROW;
}else{
int nDoclist = 0; /* Size of doclist */
sqlite3_int64 iPrev = 0; /* Previous docid stored in doclist */
/* The current term of the first nMerge entries in the array
** of Fts3SegReader objects is the same. The doclists must be merged
** and a single term returned with the merged doclist.
*/
for(i=0; i<nMerge; i++){
fts3SegReaderFirstDocid(p, apSegment[i]);
}
fts3SegReaderSort(apSegment, nMerge, nMerge, xCmp);
while( apSegment[0]->pOffsetList ){
int j; /* Number of segments that share a docid */
char *pList = 0;
int nList = 0;
int nByte;
sqlite3_int64 iDocid = apSegment[0]->iDocid;
fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
j = 1;
while( j<nMerge
&& apSegment[j]->pOffsetList
&& apSegment[j]->iDocid==iDocid
){
fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
j++;
}
if( isColFilter ){
fts3ColumnFilter(pFilter->iCol, 0, &pList, &nList);
}
if( !isIgnoreEmpty || nList>0 ){
/* Calculate the 'docid' delta value to write into the merged
** doclist. */
sqlite3_int64 iDelta;
if( p->bDescIdx && nDoclist>0 ){
iDelta = iPrev - iDocid;
}else{
iDelta = iDocid - iPrev;
}
assert( iDelta>0 || (nDoclist==0 && iDelta==iDocid) );
assert( nDoclist>0 || iDelta==iDocid );
nByte = sqlite3Fts3VarintLen(iDelta) + (isRequirePos?nList+1:0);
if( nDoclist+nByte>pCsr->nBuffer ){
char *aNew;
pCsr->nBuffer = (nDoclist+nByte)*2;
aNew = sqlite3_realloc(pCsr->aBuffer, pCsr->nBuffer);
if( !aNew ){
return SQLITE_NOMEM;
}
pCsr->aBuffer = aNew;
}
if( isFirst ){
char *a = &pCsr->aBuffer[nDoclist];
int nWrite;
nWrite = sqlite3Fts3FirstFilter(iDelta, pList, nList, a);
if( nWrite ){
iPrev = iDocid;
nDoclist += nWrite;
}
}else{
nDoclist += sqlite3Fts3PutVarint(&pCsr->aBuffer[nDoclist], iDelta);
iPrev = iDocid;
if( isRequirePos ){
memcpy(&pCsr->aBuffer[nDoclist], pList, nList);
nDoclist += nList;
pCsr->aBuffer[nDoclist++] = '\0';
}
}
}
fts3SegReaderSort(apSegment, nMerge, j, xCmp);
}
if( nDoclist>0 ){
pCsr->aDoclist = pCsr->aBuffer;
pCsr->nDoclist = nDoclist;
rc = SQLITE_ROW;
}
}
pCsr->nAdvance = nMerge;
}while( rc==SQLITE_OK );
return rc;
}
void sqlite3Fts3SegReaderFinish(
Fts3MultiSegReader *pCsr /* Cursor object */
){
if( pCsr ){
int i;
for(i=0; i<pCsr->nSegment; i++){
sqlite3Fts3SegReaderFree(pCsr->apSegment[i]);
}
sqlite3_free(pCsr->apSegment);
sqlite3_free(pCsr->aBuffer);
pCsr->nSegment = 0;
pCsr->apSegment = 0;
pCsr->aBuffer = 0;
}
}
/*
** Decode the "end_block" field, selected by column iCol of the SELECT
** statement passed as the first argument.
**
** The "end_block" field may contain either an integer, or a text field
** containing the text representation of two non-negative integers separated
** by one or more space (0x20) characters. In the first case, set *piEndBlock
** to the integer value and *pnByte to zero before returning. In the second,
** set *piEndBlock to the first value and *pnByte to the second.
*/
static void fts3ReadEndBlockField(
sqlite3_stmt *pStmt,
int iCol,
i64 *piEndBlock,
i64 *pnByte
){
const unsigned char *zText = sqlite3_column_text(pStmt, iCol);
if( zText ){
int i;
int iMul = 1;
i64 iVal = 0;
for(i=0; zText[i]>='0' && zText[i]<='9'; i++){
iVal = iVal*10 + (zText[i] - '0');
}
*piEndBlock = iVal;
while( zText[i]==' ' ) i++;
iVal = 0;
if( zText[i]=='-' ){
i++;
iMul = -1;
}
for(/* no-op */; zText[i]>='0' && zText[i]<='9'; i++){
iVal = iVal*10 + (zText[i] - '0');
}
*pnByte = (iVal * (i64)iMul);
}
}
/*
** A segment of size nByte bytes has just been written to absolute level
** iAbsLevel. Promote any segments that should be promoted as a result.
*/
static int fts3PromoteSegments(
Fts3Table *p, /* FTS table handle */
sqlite3_int64 iAbsLevel, /* Absolute level just updated */
sqlite3_int64 nByte /* Size of new segment at iAbsLevel */
){
int rc = SQLITE_OK;
sqlite3_stmt *pRange;
rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE2, &pRange, 0);
if( rc==SQLITE_OK ){
int bOk = 0;
i64 iLast = (iAbsLevel/FTS3_SEGDIR_MAXLEVEL + 1) * FTS3_SEGDIR_MAXLEVEL - 1;
i64 nLimit = (nByte*3)/2;
/* Loop through all entries in the %_segdir table corresponding to
** segments in this index on levels greater than iAbsLevel. If there is
** at least one such segment, and it is possible to determine that all
** such segments are smaller than nLimit bytes in size, they will be
** promoted to level iAbsLevel. */
sqlite3_bind_int64(pRange, 1, iAbsLevel+1);
sqlite3_bind_int64(pRange, 2, iLast);
while( SQLITE_ROW==sqlite3_step(pRange) ){
i64 nSize = 0, dummy;
fts3ReadEndBlockField(pRange, 2, &dummy, &nSize);
if( nSize<=0 || nSize>nLimit ){
/* If nSize==0, then the %_segdir.end_block field does not not
** contain a size value. This happens if it was written by an
** old version of FTS. In this case it is not possible to determine
** the size of the segment, and so segment promotion does not
** take place. */
bOk = 0;
break;
}
bOk = 1;
}
rc = sqlite3_reset(pRange);
if( bOk ){
int iIdx = 0;
sqlite3_stmt *pUpdate1 = 0;
sqlite3_stmt *pUpdate2 = 0;
if( rc==SQLITE_OK ){
rc = fts3SqlStmt(p, SQL_UPDATE_LEVEL_IDX, &pUpdate1, 0);
}
if( rc==SQLITE_OK ){
rc = fts3SqlStmt(p, SQL_UPDATE_LEVEL, &pUpdate2, 0);
}
if( rc==SQLITE_OK ){
/* Loop through all %_segdir entries for segments in this index with
** levels equal to or greater than iAbsLevel. As each entry is visited,
** updated it to set (level = -1) and (idx = N), where N is 0 for the
** oldest segment in the range, 1 for the next oldest, and so on.
**
** In other words, move all segments being promoted to level -1,
** setting the "idx" fields as appropriate to keep them in the same
** order. The contents of level -1 (which is never used, except
** transiently here), will be moved back to level iAbsLevel below. */
sqlite3_bind_int64(pRange, 1, iAbsLevel);
while( SQLITE_ROW==sqlite3_step(pRange) ){
sqlite3_bind_int(pUpdate1, 1, iIdx++);
sqlite3_bind_int(pUpdate1, 2, sqlite3_column_int(pRange, 0));
sqlite3_bind_int(pUpdate1, 3, sqlite3_column_int(pRange, 1));
sqlite3_step(pUpdate1);
rc = sqlite3_reset(pUpdate1);
if( rc!=SQLITE_OK ){
sqlite3_reset(pRange);
break;
}
}
}
if( rc==SQLITE_OK ){
rc = sqlite3_reset(pRange);
}
/* Move level -1 to level iAbsLevel */
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pUpdate2, 1, iAbsLevel);
sqlite3_step(pUpdate2);
rc = sqlite3_reset(pUpdate2);
}
}
}
return rc;
}
/*
** Merge all level iLevel segments in the database into a single
** iLevel+1 segment. Or, if iLevel<0, merge all segments into a
** single segment with a level equal to the numerically largest level
** currently present in the database.
**
** If this function is called with iLevel<0, but there is only one
** segment in the database, SQLITE_DONE is returned immediately.
** Otherwise, if successful, SQLITE_OK is returned. If an error occurs,
** an SQLite error code is returned.
*/
static int fts3SegmentMerge(
Fts3Table *p,
int iLangid, /* Language id to merge */
int iIndex, /* Index in p->aIndex[] to merge */
int iLevel /* Level to merge */
){
int rc; /* Return code */
int iIdx = 0; /* Index of new segment */
sqlite3_int64 iNewLevel = 0; /* Level/index to create new segment at */
SegmentWriter *pWriter = 0; /* Used to write the new, merged, segment */
Fts3SegFilter filter; /* Segment term filter condition */
Fts3MultiSegReader csr; /* Cursor to iterate through level(s) */
int bIgnoreEmpty = 0; /* True to ignore empty segments */
i64 iMaxLevel = 0; /* Max level number for this index/langid */
assert( iLevel==FTS3_SEGCURSOR_ALL
|| iLevel==FTS3_SEGCURSOR_PENDING
|| iLevel>=0
);
assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
assert( iIndex>=0 && iIndex<p->nIndex );
rc = sqlite3Fts3SegReaderCursor(p, iLangid, iIndex, iLevel, 0, 0, 1, 0, &csr);
if( rc!=SQLITE_OK || csr.nSegment==0 ) goto finished;
if( iLevel!=FTS3_SEGCURSOR_PENDING ){
rc = fts3SegmentMaxLevel(p, iLangid, iIndex, &iMaxLevel);
if( rc!=SQLITE_OK ) goto finished;
}
if( iLevel==FTS3_SEGCURSOR_ALL ){
/* This call is to merge all segments in the database to a single
** segment. The level of the new segment is equal to the numerically
** greatest segment level currently present in the database for this
** index. The idx of the new segment is always 0. */
if( csr.nSegment==1 && 0==fts3SegReaderIsPending(csr.apSegment[0]) ){
rc = SQLITE_DONE;
goto finished;
}
iNewLevel = iMaxLevel;
bIgnoreEmpty = 1;
}else{
/* This call is to merge all segments at level iLevel. find the next
** available segment index at level iLevel+1. The call to
** fts3AllocateSegdirIdx() will merge the segments at level iLevel+1 to
** a single iLevel+2 segment if necessary. */
assert( FTS3_SEGCURSOR_PENDING==-1 );
iNewLevel = getAbsoluteLevel(p, iLangid, iIndex, iLevel+1);
rc = fts3AllocateSegdirIdx(p, iLangid, iIndex, iLevel+1, &iIdx);
bIgnoreEmpty = (iLevel!=FTS3_SEGCURSOR_PENDING) && (iNewLevel>iMaxLevel);
}
if( rc!=SQLITE_OK ) goto finished;
assert( csr.nSegment>0 );
assert( iNewLevel>=getAbsoluteLevel(p, iLangid, iIndex, 0) );
assert( iNewLevel<getAbsoluteLevel(p, iLangid, iIndex,FTS3_SEGDIR_MAXLEVEL) );
memset(&filter, 0, sizeof(Fts3SegFilter));
filter.flags = FTS3_SEGMENT_REQUIRE_POS;
filter.flags |= (bIgnoreEmpty ? FTS3_SEGMENT_IGNORE_EMPTY : 0);
rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
while( SQLITE_OK==rc ){
rc = sqlite3Fts3SegReaderStep(p, &csr);
if( rc!=SQLITE_ROW ) break;
rc = fts3SegWriterAdd(p, &pWriter, 1,
csr.zTerm, csr.nTerm, csr.aDoclist, csr.nDoclist);
}
if( rc!=SQLITE_OK ) goto finished;
assert( pWriter || bIgnoreEmpty );
if( iLevel!=FTS3_SEGCURSOR_PENDING ){
rc = fts3DeleteSegdir(
p, iLangid, iIndex, iLevel, csr.apSegment, csr.nSegment
);
if( rc!=SQLITE_OK ) goto finished;
}
if( pWriter ){
rc = fts3SegWriterFlush(p, pWriter, iNewLevel, iIdx);
if( rc==SQLITE_OK ){
if( iLevel==FTS3_SEGCURSOR_PENDING || iNewLevel<iMaxLevel ){
rc = fts3PromoteSegments(p, iNewLevel, pWriter->nLeafData);
}
}
}
finished:
fts3SegWriterFree(pWriter);
sqlite3Fts3SegReaderFinish(&csr);
return rc;
}
/*
** Flush the contents of pendingTerms to level 0 segments.
*/
int sqlite3Fts3PendingTermsFlush(Fts3Table *p){
int rc = SQLITE_OK;
int i;
for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
rc = fts3SegmentMerge(p, p->iPrevLangid, i, FTS3_SEGCURSOR_PENDING);
if( rc==SQLITE_DONE ) rc = SQLITE_OK;
}
sqlite3Fts3PendingTermsClear(p);
/* Determine the auto-incr-merge setting if unknown. If enabled,
** estimate the number of leaf blocks of content to be written
*/
if( rc==SQLITE_OK && p->bHasStat
&& p->nAutoincrmerge==0xff && p->nLeafAdd>0
){
sqlite3_stmt *pStmt = 0;
rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
rc = sqlite3_step(pStmt);
if( rc==SQLITE_ROW ){
p->nAutoincrmerge = sqlite3_column_int(pStmt, 0);
if( p->nAutoincrmerge==1 ) p->nAutoincrmerge = 8;
}else if( rc==SQLITE_DONE ){
p->nAutoincrmerge = 0;
}
rc = sqlite3_reset(pStmt);
}
}
return rc;
}
/*
** Encode N integers as varints into a blob.
*/
static void fts3EncodeIntArray(
int N, /* The number of integers to encode */
u32 *a, /* The integer values */
char *zBuf, /* Write the BLOB here */
int *pNBuf /* Write number of bytes if zBuf[] used here */
){
int i, j;
for(i=j=0; i<N; i++){
j += sqlite3Fts3PutVarint(&zBuf[j], (sqlite3_int64)a[i]);
}
*pNBuf = j;
}
/*
** Decode a blob of varints into N integers
*/
static void fts3DecodeIntArray(
int N, /* The number of integers to decode */
u32 *a, /* Write the integer values */
const char *zBuf, /* The BLOB containing the varints */
int nBuf /* size of the BLOB */
){
int i, j;
UNUSED_PARAMETER(nBuf);
for(i=j=0; i<N; i++){
sqlite3_int64 x;
j += sqlite3Fts3GetVarint(&zBuf[j], &x);
assert(j<=nBuf);
a[i] = (u32)(x & 0xffffffff);
}
}
/*
** Insert the sizes (in tokens) for each column of the document
** with docid equal to p->iPrevDocid. The sizes are encoded as
** a blob of varints.
*/
static void fts3InsertDocsize(
int *pRC, /* Result code */
Fts3Table *p, /* Table into which to insert */
u32 *aSz /* Sizes of each column, in tokens */
){
char *pBlob; /* The BLOB encoding of the document size */
int nBlob; /* Number of bytes in the BLOB */
sqlite3_stmt *pStmt; /* Statement used to insert the encoding */
int rc; /* Result code from subfunctions */
if( *pRC ) return;
pBlob = sqlite3_malloc( 10*p->nColumn );
if( pBlob==0 ){
*pRC = SQLITE_NOMEM;
return;
}
fts3EncodeIntArray(p->nColumn, aSz, pBlob, &nBlob);
rc = fts3SqlStmt(p, SQL_REPLACE_DOCSIZE, &pStmt, 0);
if( rc ){
sqlite3_free(pBlob);
*pRC = rc;
return;
}
sqlite3_bind_int64(pStmt, 1, p->iPrevDocid);
sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, sqlite3_free);
sqlite3_step(pStmt);
*pRC = sqlite3_reset(pStmt);
}
/*
** Record 0 of the %_stat table contains a blob consisting of N varints,
** where N is the number of user defined columns in the fts3 table plus
** two. If nCol is the number of user defined columns, then values of the
** varints are set as follows:
**
** Varint 0: Total number of rows in the table.
**
** Varint 1..nCol: For each column, the total number of tokens stored in
** the column for all rows of the table.
**
** Varint 1+nCol: The total size, in bytes, of all text values in all
** columns of all rows of the table.
**
*/
static void fts3UpdateDocTotals(
int *pRC, /* The result code */
Fts3Table *p, /* Table being updated */
u32 *aSzIns, /* Size increases */
u32 *aSzDel, /* Size decreases */
int nChng /* Change in the number of documents */
){
char *pBlob; /* Storage for BLOB written into %_stat */
int nBlob; /* Size of BLOB written into %_stat */
u32 *a; /* Array of integers that becomes the BLOB */
sqlite3_stmt *pStmt; /* Statement for reading and writing */
int i; /* Loop counter */
int rc; /* Result code from subfunctions */
const int nStat = p->nColumn+2;
if( *pRC ) return;
a = sqlite3_malloc( (sizeof(u32)+10)*nStat );
if( a==0 ){
*pRC = SQLITE_NOMEM;
return;
}
pBlob = (char*)&a[nStat];
rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
if( rc ){
sqlite3_free(a);
*pRC = rc;
return;
}
sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
if( sqlite3_step(pStmt)==SQLITE_ROW ){
fts3DecodeIntArray(nStat, a,
sqlite3_column_blob(pStmt, 0),
sqlite3_column_bytes(pStmt, 0));
}else{
memset(a, 0, sizeof(u32)*(nStat) );
}
rc = sqlite3_reset(pStmt);
if( rc!=SQLITE_OK ){
sqlite3_free(a);
*pRC = rc;
return;
}
if( nChng<0 && a[0]<(u32)(-nChng) ){
a[0] = 0;
}else{
a[0] += nChng;
}
for(i=0; i<p->nColumn+1; i++){
u32 x = a[i+1];
if( x+aSzIns[i] < aSzDel[i] ){
x = 0;
}else{
x = x + aSzIns[i] - aSzDel[i];
}
a[i+1] = x;
}
fts3EncodeIntArray(nStat, a, pBlob, &nBlob);
rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
if( rc ){
sqlite3_free(a);
*pRC = rc;
return;
}
sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, SQLITE_STATIC);
sqlite3_step(pStmt);
*pRC = sqlite3_reset(pStmt);
sqlite3_free(a);
}
/*
** Merge the entire database so that there is one segment for each
** iIndex/iLangid combination.
*/
static int fts3DoOptimize(Fts3Table *p, int bReturnDone){
int bSeenDone = 0;
int rc;
sqlite3_stmt *pAllLangid = 0;
rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
if( rc==SQLITE_OK ){
int rc2;
sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
sqlite3_bind_int(pAllLangid, 2, p->nIndex);
while( sqlite3_step(pAllLangid)==SQLITE_ROW ){
int i;
int iLangid = sqlite3_column_int(pAllLangid, 0);
for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
rc = fts3SegmentMerge(p, iLangid, i, FTS3_SEGCURSOR_ALL);
if( rc==SQLITE_DONE ){
bSeenDone = 1;
rc = SQLITE_OK;
}
}
}
rc2 = sqlite3_reset(pAllLangid);
if( rc==SQLITE_OK ) rc = rc2;
}
sqlite3Fts3SegmentsClose(p);
sqlite3Fts3PendingTermsClear(p);
return (rc==SQLITE_OK && bReturnDone && bSeenDone) ? SQLITE_DONE : rc;
}
/*
** This function is called when the user executes the following statement:
**
** INSERT INTO <tbl>(<tbl>) VALUES('rebuild');
**
** The entire FTS index is discarded and rebuilt. If the table is one
** created using the content=xxx option, then the new index is based on
** the current contents of the xxx table. Otherwise, it is rebuilt based
** on the contents of the %_content table.
*/
static int fts3DoRebuild(Fts3Table *p){
int rc; /* Return Code */
rc = fts3DeleteAll(p, 0);
if( rc==SQLITE_OK ){
u32 *aSz = 0;
u32 *aSzIns = 0;
u32 *aSzDel = 0;
sqlite3_stmt *pStmt = 0;
int nEntry = 0;
/* Compose and prepare an SQL statement to loop through the content table */
char *zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
if( !zSql ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
sqlite3_free(zSql);
}
if( rc==SQLITE_OK ){
int nByte = sizeof(u32) * (p->nColumn+1)*3;
aSz = (u32 *)sqlite3_malloc(nByte);
if( aSz==0 ){
rc = SQLITE_NOMEM;
}else{
memset(aSz, 0, nByte);
aSzIns = &aSz[p->nColumn+1];
aSzDel = &aSzIns[p->nColumn+1];
}
}
while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
int iCol;
int iLangid = langidFromSelect(p, pStmt);
rc = fts3PendingTermsDocid(p, 0, iLangid, sqlite3_column_int64(pStmt, 0));
memset(aSz, 0, sizeof(aSz[0]) * (p->nColumn+1));
for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
if( p->abNotindexed[iCol]==0 ){
const char *z = (const char *) sqlite3_column_text(pStmt, iCol+1);
rc = fts3PendingTermsAdd(p, iLangid, z, iCol, &aSz[iCol]);
aSz[p->nColumn] += sqlite3_column_bytes(pStmt, iCol+1);
}
}
if( p->bHasDocsize ){
fts3InsertDocsize(&rc, p, aSz);
}
if( rc!=SQLITE_OK ){
sqlite3_finalize(pStmt);
pStmt = 0;
}else{
nEntry++;
for(iCol=0; iCol<=p->nColumn; iCol++){
aSzIns[iCol] += aSz[iCol];
}
}
}
if( p->bFts4 ){
fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nEntry);
}
sqlite3_free(aSz);
if( pStmt ){
int rc2 = sqlite3_finalize(pStmt);
if( rc==SQLITE_OK ){
rc = rc2;
}
}
}
return rc;
}
/*
** This function opens a cursor used to read the input data for an
** incremental merge operation. Specifically, it opens a cursor to scan
** the oldest nSeg segments (idx=0 through idx=(nSeg-1)) in absolute
** level iAbsLevel.
*/
static int fts3IncrmergeCsr(
Fts3Table *p, /* FTS3 table handle */
sqlite3_int64 iAbsLevel, /* Absolute level to open */
int nSeg, /* Number of segments to merge */
Fts3MultiSegReader *pCsr /* Cursor object to populate */
){
int rc; /* Return Code */
sqlite3_stmt *pStmt = 0; /* Statement used to read %_segdir entry */
int nByte; /* Bytes allocated at pCsr->apSegment[] */
/* Allocate space for the Fts3MultiSegReader.aCsr[] array */
memset(pCsr, 0, sizeof(*pCsr));
nByte = sizeof(Fts3SegReader *) * nSeg;
pCsr->apSegment = (Fts3SegReader **)sqlite3_malloc(nByte);
if( pCsr->apSegment==0 ){
rc = SQLITE_NOMEM;
}else{
memset(pCsr->apSegment, 0, nByte);
rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
}
if( rc==SQLITE_OK ){
int i;
int rc2;
sqlite3_bind_int64(pStmt, 1, iAbsLevel);
assert( pCsr->nSegment==0 );
for(i=0; rc==SQLITE_OK && sqlite3_step(pStmt)==SQLITE_ROW && i<nSeg; i++){
rc = sqlite3Fts3SegReaderNew(i, 0,
sqlite3_column_int64(pStmt, 1), /* segdir.start_block */
sqlite3_column_int64(pStmt, 2), /* segdir.leaves_end_block */
sqlite3_column_int64(pStmt, 3), /* segdir.end_block */
sqlite3_column_blob(pStmt, 4), /* segdir.root */
sqlite3_column_bytes(pStmt, 4), /* segdir.root */
&pCsr->apSegment[i]
);
pCsr->nSegment++;
}
rc2 = sqlite3_reset(pStmt);
if( rc==SQLITE_OK ) rc = rc2;
}
return rc;
}
typedef struct IncrmergeWriter IncrmergeWriter;
typedef struct NodeWriter NodeWriter;
typedef struct Blob Blob;
typedef struct NodeReader NodeReader;
/*
** An instance of the following structure is used as a dynamic buffer
** to build up nodes or other blobs of data in.
**
** The function blobGrowBuffer() is used to extend the allocation.
*/
struct Blob {
char *a; /* Pointer to allocation */
int n; /* Number of valid bytes of data in a[] */
int nAlloc; /* Allocated size of a[] (nAlloc>=n) */
};
/*
** This structure is used to build up buffers containing segment b-tree
** nodes (blocks).
*/
struct NodeWriter {
sqlite3_int64 iBlock; /* Current block id */
Blob key; /* Last key written to the current block */
Blob block; /* Current block image */
};
/*
** An object of this type contains the state required to create or append
** to an appendable b-tree segment.
*/
struct IncrmergeWriter {
int nLeafEst; /* Space allocated for leaf blocks */
int nWork; /* Number of leaf pages flushed */
sqlite3_int64 iAbsLevel; /* Absolute level of input segments */
int iIdx; /* Index of *output* segment in iAbsLevel+1 */
sqlite3_int64 iStart; /* Block number of first allocated block */
sqlite3_int64 iEnd; /* Block number of last allocated block */
sqlite3_int64 nLeafData; /* Bytes of leaf page data so far */
u8 bNoLeafData; /* If true, store 0 for segment size */
NodeWriter aNodeWriter[FTS_MAX_APPENDABLE_HEIGHT];
};
/*
** An object of the following type is used to read data from a single
** FTS segment node. See the following functions:
**
** nodeReaderInit()
** nodeReaderNext()
** nodeReaderRelease()
*/
struct NodeReader {
const char *aNode;
int nNode;
int iOff; /* Current offset within aNode[] */
/* Output variables. Containing the current node entry. */
sqlite3_int64 iChild; /* Pointer to child node */
Blob term; /* Current term */
const char *aDoclist; /* Pointer to doclist */
int nDoclist; /* Size of doclist in bytes */
};
/*
** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
** Otherwise, if the allocation at pBlob->a is not already at least nMin
** bytes in size, extend (realloc) it to be so.
**
** If an OOM error occurs, set *pRc to SQLITE_NOMEM and leave pBlob->a
** unmodified. Otherwise, if the allocation succeeds, update pBlob->nAlloc
** to reflect the new size of the pBlob->a[] buffer.
*/
static void blobGrowBuffer(Blob *pBlob, int nMin, int *pRc){
if( *pRc==SQLITE_OK && nMin>pBlob->nAlloc ){
int nAlloc = nMin;
char *a = (char *)sqlite3_realloc(pBlob->a, nAlloc);
if( a ){
pBlob->nAlloc = nAlloc;
pBlob->a = a;
}else{
*pRc = SQLITE_NOMEM;
}
}
}
/*
** Attempt to advance the node-reader object passed as the first argument to
** the next entry on the node.
**
** Return an error code if an error occurs (SQLITE_NOMEM is possible).
** Otherwise return SQLITE_OK. If there is no next entry on the node
** (e.g. because the current entry is the last) set NodeReader->aNode to
** NULL to indicate EOF. Otherwise, populate the NodeReader structure output
** variables for the new entry.
*/
static int nodeReaderNext(NodeReader *p){
int bFirst = (p->term.n==0); /* True for first term on the node */
int nPrefix = 0; /* Bytes to copy from previous term */
int nSuffix = 0; /* Bytes to append to the prefix */
int rc = SQLITE_OK; /* Return code */
assert( p->aNode );
if( p->iChild && bFirst==0 ) p->iChild++;
if( p->iOff>=p->nNode ){
/* EOF */
p->aNode = 0;
}else{
if( bFirst==0 ){
p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nPrefix);
}
p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nSuffix);
blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
if( rc==SQLITE_OK ){
memcpy(&p->term.a[nPrefix], &p->aNode[p->iOff], nSuffix);
p->term.n = nPrefix+nSuffix;
p->iOff += nSuffix;
if( p->iChild==0 ){
p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &p->nDoclist);
p->aDoclist = &p->aNode[p->iOff];
p->iOff += p->nDoclist;
}
}
}
assert( p->iOff<=p->nNode );
return rc;
}
/*
** Release all dynamic resources held by node-reader object *p.
*/
static void nodeReaderRelease(NodeReader *p){
sqlite3_free(p->term.a);
}
/*
** Initialize a node-reader object to read the node in buffer aNode/nNode.
**
** If successful, SQLITE_OK is returned and the NodeReader object set to
** point to the first entry on the node (if any). Otherwise, an SQLite
** error code is returned.
*/
static int nodeReaderInit(NodeReader *p, const char *aNode, int nNode){
memset(p, 0, sizeof(NodeReader));
p->aNode = aNode;
p->nNode = nNode;
/* Figure out if this is a leaf or an internal node. */
if( p->aNode[0] ){
/* An internal node. */
p->iOff = 1 + sqlite3Fts3GetVarint(&p->aNode[1], &p->iChild);
}else{
p->iOff = 1;
}
return nodeReaderNext(p);
}
/*
** This function is called while writing an FTS segment each time a leaf o
** node is finished and written to disk. The key (zTerm/nTerm) is guaranteed
** to be greater than the largest key on the node just written, but smaller
** than or equal to the first key that will be written to the next leaf
** node.
**
** The block id of the leaf node just written to disk may be found in
** (pWriter->aNodeWriter[0].iBlock) when this function is called.
*/
static int fts3IncrmergePush(
Fts3Table *p, /* Fts3 table handle */
IncrmergeWriter *pWriter, /* Writer object */
const char *zTerm, /* Term to write to internal node */
int nTerm /* Bytes at zTerm */
){
sqlite3_int64 iPtr = pWriter->aNodeWriter[0].iBlock;
int iLayer;
assert( nTerm>0 );
for(iLayer=1; ALWAYS(iLayer<FTS_MAX_APPENDABLE_HEIGHT); iLayer++){
sqlite3_int64 iNextPtr = 0;
NodeWriter *pNode = &pWriter->aNodeWriter[iLayer];
int rc = SQLITE_OK;
int nPrefix;
int nSuffix;
int nSpace;
/* Figure out how much space the key will consume if it is written to
** the current node of layer iLayer. Due to the prefix compression,
** the space required changes depending on which node the key is to
** be added to. */
nPrefix = fts3PrefixCompress(pNode->key.a, pNode->key.n, zTerm, nTerm);
nSuffix = nTerm - nPrefix;
nSpace = sqlite3Fts3VarintLen(nPrefix);
nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
if( pNode->key.n==0 || (pNode->block.n + nSpace)<=p->nNodeSize ){
/* If the current node of layer iLayer contains zero keys, or if adding
** the key to it will not cause it to grow to larger than nNodeSize
** bytes in size, write the key here. */
Blob *pBlk = &pNode->block;
if( pBlk->n==0 ){
blobGrowBuffer(pBlk, p->nNodeSize, &rc);
if( rc==SQLITE_OK ){
pBlk->a[0] = (char)iLayer;
pBlk->n = 1 + sqlite3Fts3PutVarint(&pBlk->a[1], iPtr);
}
}
blobGrowBuffer(pBlk, pBlk->n + nSpace, &rc);
blobGrowBuffer(&pNode->key, nTerm, &rc);
if( rc==SQLITE_OK ){
if( pNode->key.n ){
pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nPrefix);
}
pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nSuffix);
memcpy(&pBlk->a[pBlk->n], &zTerm[nPrefix], nSuffix);
pBlk->n += nSuffix;
memcpy(pNode->key.a, zTerm, nTerm);
pNode->key.n = nTerm;
}
}else{
/* Otherwise, flush the current node of layer iLayer to disk.
** Then allocate a new, empty sibling node. The key will be written
** into the parent of this node. */
rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
assert( pNode->block.nAlloc>=p->nNodeSize );
pNode->block.a[0] = (char)iLayer;
pNode->block.n = 1 + sqlite3Fts3PutVarint(&pNode->block.a[1], iPtr+1);
iNextPtr = pNode->iBlock;
pNode->iBlock++;
pNode->key.n = 0;
}
if( rc!=SQLITE_OK || iNextPtr==0 ) return rc;
iPtr = iNextPtr;
}
assert( 0 );
return 0;
}
/*
** Append a term and (optionally) doclist to the FTS segment node currently
** stored in blob *pNode. The node need not contain any terms, but the
** header must be written before this function is called.
**
** A node header is a single 0x00 byte for a leaf node, or a height varint
** followed by the left-hand-child varint for an internal node.
**
** The term to be appended is passed via arguments zTerm/nTerm. For a
** leaf node, the doclist is passed as aDoclist/nDoclist. For an internal
** node, both aDoclist and nDoclist must be passed 0.
**
** If the size of the value in blob pPrev is zero, then this is the first
** term written to the node. Otherwise, pPrev contains a copy of the
** previous term. Before this function returns, it is updated to contain a
** copy of zTerm/nTerm.
**
** It is assumed that the buffer associated with pNode is already large
** enough to accommodate the new entry. The buffer associated with pPrev
** is extended by this function if requrired.
**
** If an error (i.e. OOM condition) occurs, an SQLite error code is
** returned. Otherwise, SQLITE_OK.
*/
static int fts3AppendToNode(
Blob *pNode, /* Current node image to append to */
Blob *pPrev, /* Buffer containing previous term written */
const char *zTerm, /* New term to write */
int nTerm, /* Size of zTerm in bytes */
const char *aDoclist, /* Doclist (or NULL) to write */
int nDoclist /* Size of aDoclist in bytes */
){
int rc = SQLITE_OK; /* Return code */
int bFirst = (pPrev->n==0); /* True if this is the first term written */
int nPrefix; /* Size of term prefix in bytes */
int nSuffix; /* Size of term suffix in bytes */
/* Node must have already been started. There must be a doclist for a
** leaf node, and there must not be a doclist for an internal node. */
assert( pNode->n>0 );
assert( (pNode->a[0]=='\0')==(aDoclist!=0) );
blobGrowBuffer(pPrev, nTerm, &rc);
if( rc!=SQLITE_OK ) return rc;
nPrefix = fts3PrefixCompress(pPrev->a, pPrev->n, zTerm, nTerm);
nSuffix = nTerm - nPrefix;
memcpy(pPrev->a, zTerm, nTerm);
pPrev->n = nTerm;
if( bFirst==0 ){
pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nPrefix);
}
pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nSuffix);
memcpy(&pNode->a[pNode->n], &zTerm[nPrefix], nSuffix);
pNode->n += nSuffix;
if( aDoclist ){
pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nDoclist);
memcpy(&pNode->a[pNode->n], aDoclist, nDoclist);
pNode->n += nDoclist;
}
assert( pNode->n<=pNode->nAlloc );
return SQLITE_OK;
}
/*
** Append the current term and doclist pointed to by cursor pCsr to the
** appendable b-tree segment opened for writing by pWriter.
**
** Return SQLITE_OK if successful, or an SQLite error code otherwise.
*/
static int fts3IncrmergeAppend(
Fts3Table *p, /* Fts3 table handle */
IncrmergeWriter *pWriter, /* Writer object */
Fts3MultiSegReader *pCsr /* Cursor containing term and doclist */
){
const char *zTerm = pCsr->zTerm;
int nTerm = pCsr->nTerm;
const char *aDoclist = pCsr->aDoclist;
int nDoclist = pCsr->nDoclist;
int rc = SQLITE_OK; /* Return code */
int nSpace; /* Total space in bytes required on leaf */
int nPrefix; /* Size of prefix shared with previous term */
int nSuffix; /* Size of suffix (nTerm - nPrefix) */
NodeWriter *pLeaf; /* Object used to write leaf nodes */
pLeaf = &pWriter->aNodeWriter[0];
nPrefix = fts3PrefixCompress(pLeaf->key.a, pLeaf->key.n, zTerm, nTerm);
nSuffix = nTerm - nPrefix;
nSpace = sqlite3Fts3VarintLen(nPrefix);
nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
/* If the current block is not empty, and if adding this term/doclist
** to the current block would make it larger than Fts3Table.nNodeSize
** bytes, write this block out to the database. */
if( pLeaf->block.n>0 && (pLeaf->block.n + nSpace)>p->nNodeSize ){
rc = fts3WriteSegment(p, pLeaf->iBlock, pLeaf->block.a, pLeaf->block.n);
pWriter->nWork++;
/* Add the current term to the parent node. The term added to the
** parent must:
**
** a) be greater than the largest term on the leaf node just written
** to the database (still available in pLeaf->key), and
**
** b) be less than or equal to the term about to be added to the new
** leaf node (zTerm/nTerm).
**
** In other words, it must be the prefix of zTerm 1 byte longer than
** the common prefix (if any) of zTerm and pWriter->zTerm.
*/
if( rc==SQLITE_OK ){
rc = fts3IncrmergePush(p, pWriter, zTerm, nPrefix+1);
}
/* Advance to the next output block */
pLeaf->iBlock++;
pLeaf->key.n = 0;
pLeaf->block.n = 0;
nSuffix = nTerm;
nSpace = 1;
nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
}
pWriter->nLeafData += nSpace;
blobGrowBuffer(&pLeaf->block, pLeaf->block.n + nSpace, &rc);
if( rc==SQLITE_OK ){
if( pLeaf->block.n==0 ){
pLeaf->block.n = 1;
pLeaf->block.a[0] = '\0';
}
rc = fts3AppendToNode(
&pLeaf->block, &pLeaf->key, zTerm, nTerm, aDoclist, nDoclist
);
}
return rc;
}
/*
** This function is called to release all dynamic resources held by the
** merge-writer object pWriter, and if no error has occurred, to flush
** all outstanding node buffers held by pWriter to disk.
**
** If *pRc is not SQLITE_OK when this function is called, then no attempt
** is made to write any data to disk. Instead, this function serves only
** to release outstanding resources.
**
** Otherwise, if *pRc is initially SQLITE_OK and an error occurs while
** flushing buffers to disk, *pRc is set to an SQLite error code before
** returning.
*/
static void fts3IncrmergeRelease(
Fts3Table *p, /* FTS3 table handle */
IncrmergeWriter *pWriter, /* Merge-writer object */
int *pRc /* IN/OUT: Error code */
){
int i; /* Used to iterate through non-root layers */
int iRoot; /* Index of root in pWriter->aNodeWriter */
NodeWriter *pRoot; /* NodeWriter for root node */
int rc = *pRc; /* Error code */
/* Set iRoot to the index in pWriter->aNodeWriter[] of the output segment
** root node. If the segment fits entirely on a single leaf node, iRoot
** will be set to 0. If the root node is the parent of the leaves, iRoot
** will be 1. And so on. */
for(iRoot=FTS_MAX_APPENDABLE_HEIGHT-1; iRoot>=0; iRoot--){
NodeWriter *pNode = &pWriter->aNodeWriter[iRoot];
if( pNode->block.n>0 ) break;
assert( *pRc || pNode->block.nAlloc==0 );
assert( *pRc || pNode->key.nAlloc==0 );
sqlite3_free(pNode->block.a);
sqlite3_free(pNode->key.a);
}
/* Empty output segment. This is a no-op. */
if( iRoot<0 ) return;
/* The entire output segment fits on a single node. Normally, this means
** the node would be stored as a blob in the "root" column of the %_segdir
** table. However, this is not permitted in this case. The problem is that
** space has already been reserved in the %_segments table, and so the
** start_block and end_block fields of the %_segdir table must be populated.
** And, by design or by accident, released versions of FTS cannot handle
** segments that fit entirely on the root node with start_block!=0.
**
** Instead, create a synthetic root node that contains nothing but a
** pointer to the single content node. So that the segment consists of a
** single leaf and a single interior (root) node.
**
** Todo: Better might be to defer allocating space in the %_segments
** table until we are sure it is needed.
*/
if( iRoot==0 ){
Blob *pBlock = &pWriter->aNodeWriter[1].block;
blobGrowBuffer(pBlock, 1 + FTS3_VARINT_MAX, &rc);
if( rc==SQLITE_OK ){
pBlock->a[0] = 0x01;
pBlock->n = 1 + sqlite3Fts3PutVarint(
&pBlock->a[1], pWriter->aNodeWriter[0].iBlock
);
}
iRoot = 1;
}
pRoot = &pWriter->aNodeWriter[iRoot];
/* Flush all currently outstanding nodes to disk. */
for(i=0; i<iRoot; i++){
NodeWriter *pNode = &pWriter->aNodeWriter[i];
if( pNode->block.n>0 && rc==SQLITE_OK ){
rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
}
sqlite3_free(pNode->block.a);
sqlite3_free(pNode->key.a);
}
/* Write the %_segdir record. */
if( rc==SQLITE_OK ){
rc = fts3WriteSegdir(p,
pWriter->iAbsLevel+1, /* level */
pWriter->iIdx, /* idx */
pWriter->iStart, /* start_block */
pWriter->aNodeWriter[0].iBlock, /* leaves_end_block */
pWriter->iEnd, /* end_block */
(pWriter->bNoLeafData==0 ? pWriter->nLeafData : 0), /* end_block */
pRoot->block.a, pRoot->block.n /* root */
);
}
sqlite3_free(pRoot->block.a);
sqlite3_free(pRoot->key.a);
*pRc = rc;
}
/*
** Compare the term in buffer zLhs (size in bytes nLhs) with that in
** zRhs (size in bytes nRhs) using memcmp. If one term is a prefix of
** the other, it is considered to be smaller than the other.
**
** Return -ve if zLhs is smaller than zRhs, 0 if it is equal, or +ve
** if it is greater.
*/
static int fts3TermCmp(
const char *zLhs, int nLhs, /* LHS of comparison */
const char *zRhs, int nRhs /* RHS of comparison */
){
int nCmp = MIN(nLhs, nRhs);
int res;
res = memcmp(zLhs, zRhs, nCmp);
if( res==0 ) res = nLhs - nRhs;
return res;
}
/*
** Query to see if the entry in the %_segments table with blockid iEnd is
** NULL. If no error occurs and the entry is NULL, set *pbRes 1 before
** returning. Otherwise, set *pbRes to 0.
**
** Or, if an error occurs while querying the database, return an SQLite
** error code. The final value of *pbRes is undefined in this case.
**
** This is used to test if a segment is an "appendable" segment. If it
** is, then a NULL entry has been inserted into the %_segments table
** with blockid %_segdir.end_block.
*/
static int fts3IsAppendable(Fts3Table *p, sqlite3_int64 iEnd, int *pbRes){
int bRes = 0; /* Result to set *pbRes to */
sqlite3_stmt *pCheck = 0; /* Statement to query database with */
int rc; /* Return code */
rc = fts3SqlStmt(p, SQL_SEGMENT_IS_APPENDABLE, &pCheck, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pCheck, 1, iEnd);
if( SQLITE_ROW==sqlite3_step(pCheck) ) bRes = 1;
rc = sqlite3_reset(pCheck);
}
*pbRes = bRes;
return rc;
}
/*
** This function is called when initializing an incremental-merge operation.
** It checks if the existing segment with index value iIdx at absolute level
** (iAbsLevel+1) can be appended to by the incremental merge. If it can, the
** merge-writer object *pWriter is initialized to write to it.
**
** An existing segment can be appended to by an incremental merge if:
**
** * It was initially created as an appendable segment (with all required
** space pre-allocated), and
**
** * The first key read from the input (arguments zKey and nKey) is
** greater than the largest key currently stored in the potential
** output segment.
*/
static int fts3IncrmergeLoad(
Fts3Table *p, /* Fts3 table handle */
sqlite3_int64 iAbsLevel, /* Absolute level of input segments */
int iIdx, /* Index of candidate output segment */
const char *zKey, /* First key to write */
int nKey, /* Number of bytes in nKey */
IncrmergeWriter *pWriter /* Populate this object */
){
int rc; /* Return code */
sqlite3_stmt *pSelect = 0; /* SELECT to read %_segdir entry */
rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pSelect, 0);
if( rc==SQLITE_OK ){
sqlite3_int64 iStart = 0; /* Value of %_segdir.start_block */
sqlite3_int64 iLeafEnd = 0; /* Value of %_segdir.leaves_end_block */
sqlite3_int64 iEnd = 0; /* Value of %_segdir.end_block */
const char *aRoot = 0; /* Pointer to %_segdir.root buffer */
int nRoot = 0; /* Size of aRoot[] in bytes */
int rc2; /* Return code from sqlite3_reset() */
int bAppendable = 0; /* Set to true if segment is appendable */
/* Read the %_segdir entry for index iIdx absolute level (iAbsLevel+1) */
sqlite3_bind_int64(pSelect, 1, iAbsLevel+1);
sqlite3_bind_int(pSelect, 2, iIdx);
if( sqlite3_step(pSelect)==SQLITE_ROW ){
iStart = sqlite3_column_int64(pSelect, 1);
iLeafEnd = sqlite3_column_int64(pSelect, 2);
fts3ReadEndBlockField(pSelect, 3, &iEnd, &pWriter->nLeafData);
if( pWriter->nLeafData<0 ){
pWriter->nLeafData = pWriter->nLeafData * -1;
}
pWriter->bNoLeafData = (pWriter->nLeafData==0);
nRoot = sqlite3_column_bytes(pSelect, 4);
aRoot = sqlite3_column_blob(pSelect, 4);
}else{
return sqlite3_reset(pSelect);
}
/* Check for the zero-length marker in the %_segments table */
rc = fts3IsAppendable(p, iEnd, &bAppendable);
/* Check that zKey/nKey is larger than the largest key the candidate */
if( rc==SQLITE_OK && bAppendable ){
char *aLeaf = 0;
int nLeaf = 0;
rc = sqlite3Fts3ReadBlock(p, iLeafEnd, &aLeaf, &nLeaf, 0);
if( rc==SQLITE_OK ){
NodeReader reader;
for(rc = nodeReaderInit(&reader, aLeaf, nLeaf);
rc==SQLITE_OK && reader.aNode;
rc = nodeReaderNext(&reader)
){
assert( reader.aNode );
}
if( fts3TermCmp(zKey, nKey, reader.term.a, reader.term.n)<=0 ){
bAppendable = 0;
}
nodeReaderRelease(&reader);
}
sqlite3_free(aLeaf);
}
if( rc==SQLITE_OK && bAppendable ){
/* It is possible to append to this segment. Set up the IncrmergeWriter
** object to do so. */
int i;
int nHeight = (int)aRoot[0];
NodeWriter *pNode;
pWriter->nLeafEst = (int)((iEnd - iStart) + 1)/FTS_MAX_APPENDABLE_HEIGHT;
pWriter->iStart = iStart;
pWriter->iEnd = iEnd;
pWriter->iAbsLevel = iAbsLevel;
pWriter->iIdx = iIdx;
for(i=nHeight+1; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
}
pNode = &pWriter->aNodeWriter[nHeight];
pNode->iBlock = pWriter->iStart + pWriter->nLeafEst*nHeight;
blobGrowBuffer(&pNode->block, MAX(nRoot, p->nNodeSize), &rc);
if( rc==SQLITE_OK ){
memcpy(pNode->block.a, aRoot, nRoot);
pNode->block.n = nRoot;
}
for(i=nHeight; i>=0 && rc==SQLITE_OK; i--){
NodeReader reader;
pNode = &pWriter->aNodeWriter[i];
rc = nodeReaderInit(&reader, pNode->block.a, pNode->block.n);
while( reader.aNode && rc==SQLITE_OK ) rc = nodeReaderNext(&reader);
blobGrowBuffer(&pNode->key, reader.term.n, &rc);
if( rc==SQLITE_OK ){
memcpy(pNode->key.a, reader.term.a, reader.term.n);
pNode->key.n = reader.term.n;
if( i>0 ){
char *aBlock = 0;
int nBlock = 0;
pNode = &pWriter->aNodeWriter[i-1];
pNode->iBlock = reader.iChild;
rc = sqlite3Fts3ReadBlock(p, reader.iChild, &aBlock, &nBlock, 0);
blobGrowBuffer(&pNode->block, MAX(nBlock, p->nNodeSize), &rc);
if( rc==SQLITE_OK ){
memcpy(pNode->block.a, aBlock, nBlock);
pNode->block.n = nBlock;
}
sqlite3_free(aBlock);
}
}
nodeReaderRelease(&reader);
}
}
rc2 = sqlite3_reset(pSelect);
if( rc==SQLITE_OK ) rc = rc2;
}
return rc;
}
/*
** Determine the largest segment index value that exists within absolute
** level iAbsLevel+1. If no error occurs, set *piIdx to this value plus
** one before returning SQLITE_OK. Or, if there are no segments at all
** within level iAbsLevel, set *piIdx to zero.
**
** If an error occurs, return an SQLite error code. The final value of
** *piIdx is undefined in this case.
*/
static int fts3IncrmergeOutputIdx(
Fts3Table *p, /* FTS Table handle */
sqlite3_int64 iAbsLevel, /* Absolute index of input segments */
int *piIdx /* OUT: Next free index at iAbsLevel+1 */
){
int rc;
sqlite3_stmt *pOutputIdx = 0; /* SQL used to find output index */
rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pOutputIdx, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pOutputIdx, 1, iAbsLevel+1);
sqlite3_step(pOutputIdx);
*piIdx = sqlite3_column_int(pOutputIdx, 0);
rc = sqlite3_reset(pOutputIdx);
}
return rc;
}
/*
** Allocate an appendable output segment on absolute level iAbsLevel+1
** with idx value iIdx.
**
** In the %_segdir table, a segment is defined by the values in three
** columns:
**
** start_block
** leaves_end_block
** end_block
**
** When an appendable segment is allocated, it is estimated that the
** maximum number of leaf blocks that may be required is the sum of the
** number of leaf blocks consumed by the input segments, plus the number
** of input segments, multiplied by two. This value is stored in stack
** variable nLeafEst.
**
** A total of 16*nLeafEst blocks are allocated when an appendable segment
** is created ((1 + end_block - start_block)==16*nLeafEst). The contiguous
** array of leaf nodes starts at the first block allocated. The array
** of interior nodes that are parents of the leaf nodes start at block
** (start_block + (1 + end_block - start_block) / 16). And so on.
**
** In the actual code below, the value "16" is replaced with the
** pre-processor macro FTS_MAX_APPENDABLE_HEIGHT.
*/
static int fts3IncrmergeWriter(
Fts3Table *p, /* Fts3 table handle */
sqlite3_int64 iAbsLevel, /* Absolute level of input segments */
int iIdx, /* Index of new output segment */
Fts3MultiSegReader *pCsr, /* Cursor that data will be read from */
IncrmergeWriter *pWriter /* Populate this object */
){
int rc; /* Return Code */
int i; /* Iterator variable */
int nLeafEst = 0; /* Blocks allocated for leaf nodes */
sqlite3_stmt *pLeafEst = 0; /* SQL used to determine nLeafEst */
sqlite3_stmt *pFirstBlock = 0; /* SQL used to determine first block */
/* Calculate nLeafEst. */
rc = fts3SqlStmt(p, SQL_MAX_LEAF_NODE_ESTIMATE, &pLeafEst, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pLeafEst, 1, iAbsLevel);
sqlite3_bind_int64(pLeafEst, 2, pCsr->nSegment);
if( SQLITE_ROW==sqlite3_step(pLeafEst) ){
nLeafEst = sqlite3_column_int(pLeafEst, 0);
}
rc = sqlite3_reset(pLeafEst);
}
if( rc!=SQLITE_OK ) return rc;
/* Calculate the first block to use in the output segment */
rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pFirstBlock, 0);
if( rc==SQLITE_OK ){
if( SQLITE_ROW==sqlite3_step(pFirstBlock) ){
pWriter->iStart = sqlite3_column_int64(pFirstBlock, 0);
pWriter->iEnd = pWriter->iStart - 1;
pWriter->iEnd += nLeafEst * FTS_MAX_APPENDABLE_HEIGHT;
}
rc = sqlite3_reset(pFirstBlock);
}
if( rc!=SQLITE_OK ) return rc;
/* Insert the marker in the %_segments table to make sure nobody tries
** to steal the space just allocated. This is also used to identify
** appendable segments. */
rc = fts3WriteSegment(p, pWriter->iEnd, 0, 0);
if( rc!=SQLITE_OK ) return rc;
pWriter->iAbsLevel = iAbsLevel;
pWriter->nLeafEst = nLeafEst;
pWriter->iIdx = iIdx;
/* Set up the array of NodeWriter objects */
for(i=0; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
}
return SQLITE_OK;
}
/*
** Remove an entry from the %_segdir table. This involves running the
** following two statements:
**
** DELETE FROM %_segdir WHERE level = :iAbsLevel AND idx = :iIdx
** UPDATE %_segdir SET idx = idx - 1 WHERE level = :iAbsLevel AND idx > :iIdx
**
** The DELETE statement removes the specific %_segdir level. The UPDATE
** statement ensures that the remaining segments have contiguously allocated
** idx values.
*/
static int fts3RemoveSegdirEntry(
Fts3Table *p, /* FTS3 table handle */
sqlite3_int64 iAbsLevel, /* Absolute level to delete from */
int iIdx /* Index of %_segdir entry to delete */
){
int rc; /* Return code */
sqlite3_stmt *pDelete = 0; /* DELETE statement */
rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_ENTRY, &pDelete, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pDelete, 1, iAbsLevel);
sqlite3_bind_int(pDelete, 2, iIdx);
sqlite3_step(pDelete);
rc = sqlite3_reset(pDelete);
}
return rc;
}
/*
** One or more segments have just been removed from absolute level iAbsLevel.
** Update the 'idx' values of the remaining segments in the level so that
** the idx values are a contiguous sequence starting from 0.
*/
static int fts3RepackSegdirLevel(
Fts3Table *p, /* FTS3 table handle */
sqlite3_int64 iAbsLevel /* Absolute level to repack */
){
int rc; /* Return code */
int *aIdx = 0; /* Array of remaining idx values */
int nIdx = 0; /* Valid entries in aIdx[] */
int nAlloc = 0; /* Allocated size of aIdx[] */
int i; /* Iterator variable */
sqlite3_stmt *pSelect = 0; /* Select statement to read idx values */
sqlite3_stmt *pUpdate = 0; /* Update statement to modify idx values */
rc = fts3SqlStmt(p, SQL_SELECT_INDEXES, &pSelect, 0);
if( rc==SQLITE_OK ){
int rc2;
sqlite3_bind_int64(pSelect, 1, iAbsLevel);
while( SQLITE_ROW==sqlite3_step(pSelect) ){
if( nIdx>=nAlloc ){
int *aNew;
nAlloc += 16;
aNew = sqlite3_realloc(aIdx, nAlloc*sizeof(int));
if( !aNew ){
rc = SQLITE_NOMEM;
break;
}
aIdx = aNew;
}
aIdx[nIdx++] = sqlite3_column_int(pSelect, 0);
}
rc2 = sqlite3_reset(pSelect);
if( rc==SQLITE_OK ) rc = rc2;
}
if( rc==SQLITE_OK ){
rc = fts3SqlStmt(p, SQL_SHIFT_SEGDIR_ENTRY, &pUpdate, 0);
}
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pUpdate, 2, iAbsLevel);
}
assert( p->bIgnoreSavepoint==0 );
p->bIgnoreSavepoint = 1;
for(i=0; rc==SQLITE_OK && i<nIdx; i++){
if( aIdx[i]!=i ){
sqlite3_bind_int(pUpdate, 3, aIdx[i]);
sqlite3_bind_int(pUpdate, 1, i);
sqlite3_step(pUpdate);
rc = sqlite3_reset(pUpdate);
}
}
p->bIgnoreSavepoint = 0;
sqlite3_free(aIdx);
return rc;
}
static void fts3StartNode(Blob *pNode, int iHeight, sqlite3_int64 iChild){
pNode->a[0] = (char)iHeight;
if( iChild ){
assert( pNode->nAlloc>=1+sqlite3Fts3VarintLen(iChild) );
pNode->n = 1 + sqlite3Fts3PutVarint(&pNode->a[1], iChild);
}else{
assert( pNode->nAlloc>=1 );
pNode->n = 1;
}
}
/*
** The first two arguments are a pointer to and the size of a segment b-tree
** node. The node may be a leaf or an internal node.
**
** This function creates a new node image in blob object *pNew by copying
** all terms that are greater than or equal to zTerm/nTerm (for leaf nodes)
** or greater than zTerm/nTerm (for internal nodes) from aNode/nNode.
*/
static int fts3TruncateNode(
const char *aNode, /* Current node image */
int nNode, /* Size of aNode in bytes */
Blob *pNew, /* OUT: Write new node image here */
const char *zTerm, /* Omit all terms smaller than this */
int nTerm, /* Size of zTerm in bytes */
sqlite3_int64 *piBlock /* OUT: Block number in next layer down */
){
NodeReader reader; /* Reader object */
Blob prev = {0, 0, 0}; /* Previous term written to new node */
int rc = SQLITE_OK; /* Return code */
int bLeaf = aNode[0]=='\0'; /* True for a leaf node */
/* Allocate required output space */
blobGrowBuffer(pNew, nNode, &rc);
if( rc!=SQLITE_OK ) return rc;
pNew->n = 0;
/* Populate new node buffer */
for(rc = nodeReaderInit(&reader, aNode, nNode);
rc==SQLITE_OK && reader.aNode;
rc = nodeReaderNext(&reader)
){
if( pNew->n==0 ){
int res = fts3TermCmp(reader.term.a, reader.term.n, zTerm, nTerm);
if( res<0 || (bLeaf==0 && res==0) ) continue;
fts3StartNode(pNew, (int)aNode[0], reader.iChild);
*piBlock = reader.iChild;
}
rc = fts3AppendToNode(
pNew, &prev, reader.term.a, reader.term.n,
reader.aDoclist, reader.nDoclist
);
if( rc!=SQLITE_OK ) break;
}
if( pNew->n==0 ){
fts3StartNode(pNew, (int)aNode[0], reader.iChild);
*piBlock = reader.iChild;
}
assert( pNew->n<=pNew->nAlloc );
nodeReaderRelease(&reader);
sqlite3_free(prev.a);
return rc;
}
/*
** Remove all terms smaller than zTerm/nTerm from segment iIdx in absolute
** level iAbsLevel. This may involve deleting entries from the %_segments
** table, and modifying existing entries in both the %_segments and %_segdir
** tables.
**
** SQLITE_OK is returned if the segment is updated successfully. Or an
** SQLite error code otherwise.
*/
static int fts3TruncateSegment(
Fts3Table *p, /* FTS3 table handle */
sqlite3_int64 iAbsLevel, /* Absolute level of segment to modify */
int iIdx, /* Index within level of segment to modify */
const char *zTerm, /* Remove terms smaller than this */
int nTerm /* Number of bytes in buffer zTerm */
){
int rc = SQLITE_OK; /* Return code */
Blob root = {0,0,0}; /* New root page image */
Blob block = {0,0,0}; /* Buffer used for any other block */
sqlite3_int64 iBlock = 0; /* Block id */
sqlite3_int64 iNewStart = 0; /* New value for iStartBlock */
sqlite3_int64 iOldStart = 0; /* Old value for iStartBlock */
sqlite3_stmt *pFetch = 0; /* Statement used to fetch segdir */
rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pFetch, 0);
if( rc==SQLITE_OK ){
int rc2; /* sqlite3_reset() return code */
sqlite3_bind_int64(pFetch, 1, iAbsLevel);
sqlite3_bind_int(pFetch, 2, iIdx);
if( SQLITE_ROW==sqlite3_step(pFetch) ){
const char *aRoot = sqlite3_column_blob(pFetch, 4);
int nRoot = sqlite3_column_bytes(pFetch, 4);
iOldStart = sqlite3_column_int64(pFetch, 1);
rc = fts3TruncateNode(aRoot, nRoot, &root, zTerm, nTerm, &iBlock);
}
rc2 = sqlite3_reset(pFetch);
if( rc==SQLITE_OK ) rc = rc2;
}
while( rc==SQLITE_OK && iBlock ){
char *aBlock = 0;
int nBlock = 0;
iNewStart = iBlock;
rc = sqlite3Fts3ReadBlock(p, iBlock, &aBlock, &nBlock, 0);
if( rc==SQLITE_OK ){
rc = fts3TruncateNode(aBlock, nBlock, &block, zTerm, nTerm, &iBlock);
}
if( rc==SQLITE_OK ){
rc = fts3WriteSegment(p, iNewStart, block.a, block.n);
}
sqlite3_free(aBlock);
}
/* Variable iNewStart now contains the first valid leaf node. */
if( rc==SQLITE_OK && iNewStart ){
sqlite3_stmt *pDel = 0;
rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDel, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pDel, 1, iOldStart);
sqlite3_bind_int64(pDel, 2, iNewStart-1);
sqlite3_step(pDel);
rc = sqlite3_reset(pDel);
}
}
if( rc==SQLITE_OK ){
sqlite3_stmt *pChomp = 0;
rc = fts3SqlStmt(p, SQL_CHOMP_SEGDIR, &pChomp, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int64(pChomp, 1, iNewStart);
sqlite3_bind_blob(pChomp, 2, root.a, root.n, SQLITE_STATIC);
sqlite3_bind_int64(pChomp, 3, iAbsLevel);
sqlite3_bind_int(pChomp, 4, iIdx);
sqlite3_step(pChomp);
rc = sqlite3_reset(pChomp);
}
}
sqlite3_free(root.a);
sqlite3_free(block.a);
return rc;
}
/*
** This function is called after an incrmental-merge operation has run to
** merge (or partially merge) two or more segments from absolute level
** iAbsLevel.
**
** Each input segment is either removed from the db completely (if all of
** its data was copied to the output segment by the incrmerge operation)
** or modified in place so that it no longer contains those entries that
** have been duplicated in the output segment.
*/
static int fts3IncrmergeChomp(
Fts3Table *p, /* FTS table handle */
sqlite3_int64 iAbsLevel, /* Absolute level containing segments */
Fts3MultiSegReader *pCsr, /* Chomp all segments opened by this cursor */
int *pnRem /* Number of segments not deleted */
){
int i;
int nRem = 0;
int rc = SQLITE_OK;
for(i=pCsr->nSegment-1; i>=0 && rc==SQLITE_OK; i--){
Fts3SegReader *pSeg = 0;
int j;
/* Find the Fts3SegReader object with Fts3SegReader.iIdx==i. It is hiding
** somewhere in the pCsr->apSegment[] array. */
for(j=0; ALWAYS(j<pCsr->nSegment); j++){
pSeg = pCsr->apSegment[j];
if( pSeg->iIdx==i ) break;
}
assert( j<pCsr->nSegment && pSeg->iIdx==i );
if( pSeg->aNode==0 ){
/* Seg-reader is at EOF. Remove the entire input segment. */
rc = fts3DeleteSegment(p, pSeg);
if( rc==SQLITE_OK ){
rc = fts3RemoveSegdirEntry(p, iAbsLevel, pSeg->iIdx);
}
*pnRem = 0;
}else{
/* The incremental merge did not copy all the data from this
** segment to the upper level. The segment is modified in place
** so that it contains no keys smaller than zTerm/nTerm. */
const char *zTerm = pSeg->zTerm;
int nTerm = pSeg->nTerm;
rc = fts3TruncateSegment(p, iAbsLevel, pSeg->iIdx, zTerm, nTerm);
nRem++;
}
}
if( rc==SQLITE_OK && nRem!=pCsr->nSegment ){
rc = fts3RepackSegdirLevel(p, iAbsLevel);
}
*pnRem = nRem;
return rc;
}
/*
** Store an incr-merge hint in the database.
*/
static int fts3IncrmergeHintStore(Fts3Table *p, Blob *pHint){
sqlite3_stmt *pReplace = 0;
int rc; /* Return code */
rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pReplace, 0);
if( rc==SQLITE_OK ){
sqlite3_bind_int(pReplace, 1, FTS_STAT_INCRMERGEHINT);
sqlite3_bind_blob(pReplace, 2, pHint->a, pHint->n, SQLITE_STATIC);
sqlite3_step(pReplace);
rc = sqlite3_reset(pReplace);
}
return rc;
}
/*
** Load an incr-merge hint from the database. The incr-merge hint, if one
** exists, is stored in the rowid==1 row of the %_stat table.
**
** If successful, populate blob *pHint with the value read from the %_stat
** table and return SQLITE_OK. Otherwise, if an error occurs, return an
** SQLite error code.
*/
static int fts3IncrmergeHintLoad(Fts3Table *p, Blob *pHint){
sqlite3_stmt *pSelect = 0;
int rc;
pHint->n = 0;
rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pSelect, 0);
if( rc==SQLITE_OK ){
int rc2;
sqlite3_bind_int(pSelect, 1, FTS_STAT_INCRMERGEHINT);
if( SQLITE_ROW==sqlite3_step(pSelect) ){
const char *aHint = sqlite3_column_blob(pSelect, 0);
int nHint = sqlite3_column_bytes(pSelect, 0);
if( aHint ){
blobGrowBuffer(pHint, nHint, &rc);
if( rc==SQLITE_OK ){
memcpy(pHint->a, aHint, nHint);
pHint->n = nHint;
}
}
}
rc2 = sqlite3_reset(pSelect);
if( rc==SQLITE_OK ) rc = rc2;
}
return rc;
}
/*
** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
** Otherwise, append an entry to the hint stored in blob *pHint. Each entry
** consists of two varints, the absolute level number of the input segments
** and the number of input segments.
**
** If successful, leave *pRc set to SQLITE_OK and return. If an error occurs,
** set *pRc to an SQLite error code before returning.
*/
static void fts3IncrmergeHintPush(
Blob *pHint, /* Hint blob to append to */
i64 iAbsLevel, /* First varint to store in hint */
int nInput, /* Second varint to store in hint */
int *pRc /* IN/OUT: Error code */
){
blobGrowBuffer(pHint, pHint->n + 2*FTS3_VARINT_MAX, pRc);
if( *pRc==SQLITE_OK ){
pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], iAbsLevel);
pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], (i64)nInput);
}
}
/*
** Read the last entry (most recently pushed) from the hint blob *pHint
** and then remove the entry. Write the two values read to *piAbsLevel and
** *pnInput before returning.
**
** If no error occurs, return SQLITE_OK. If the hint blob in *pHint does
** not contain at least two valid varints, return SQLITE_CORRUPT_VTAB.
*/
static int fts3IncrmergeHintPop(Blob *pHint, i64 *piAbsLevel, int *pnInput){
const int nHint = pHint->n;
int i;
i = pHint->n-2;
while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
pHint->n = i;
i += sqlite3Fts3GetVarint(&pHint->a[i], piAbsLevel);
i += fts3GetVarint32(&pHint->a[i], pnInput);
if( i!=nHint ) return FTS_CORRUPT_VTAB;
return SQLITE_OK;
}
/*
** Attempt an incremental merge that writes nMerge leaf blocks.
**
** Incremental merges happen nMin segments at a time. The segments
** to be merged are the nMin oldest segments (the ones with the smallest
** values for the _segdir.idx field) in the highest level that contains
** at least nMin segments. Multiple merges might occur in an attempt to
** write the quota of nMerge leaf blocks.
*/
int sqlite3Fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){
int rc; /* Return code */
int nRem = nMerge; /* Number of leaf pages yet to be written */
Fts3MultiSegReader *pCsr; /* Cursor used to read input data */
Fts3SegFilter *pFilter; /* Filter used with cursor pCsr */
IncrmergeWriter *pWriter; /* Writer object */
int nSeg = 0; /* Number of input segments */
sqlite3_int64 iAbsLevel = 0; /* Absolute level number to work on */
Blob hint = {0, 0, 0}; /* Hint read from %_stat table */
int bDirtyHint = 0; /* True if blob 'hint' has been modified */
/* Allocate space for the cursor, filter and writer objects */
const int nAlloc = sizeof(*pCsr) + sizeof(*pFilter) + sizeof(*pWriter);
pWriter = (IncrmergeWriter *)sqlite3_malloc(nAlloc);
if( !pWriter ) return SQLITE_NOMEM;
pFilter = (Fts3SegFilter *)&pWriter[1];
pCsr = (Fts3MultiSegReader *)&pFilter[1];
rc = fts3IncrmergeHintLoad(p, &hint);
while( rc==SQLITE_OK && nRem>0 ){
const i64 nMod = FTS3_SEGDIR_MAXLEVEL * p->nIndex;
sqlite3_stmt *pFindLevel = 0; /* SQL used to determine iAbsLevel */
int bUseHint = 0; /* True if attempting to append */
int iIdx = 0; /* Largest idx in level (iAbsLevel+1) */
/* Search the %_segdir table for the absolute level with the smallest
** relative level number that contains at least nMin segments, if any.
** If one is found, set iAbsLevel to the absolute level number and
** nSeg to nMin. If no level with at least nMin segments can be found,
** set nSeg to -1.
*/
rc = fts3SqlStmt(p, SQL_FIND_MERGE_LEVEL, &pFindLevel, 0);
sqlite3_bind_int(pFindLevel, 1, MAX(2, nMin));
if( sqlite3_step(pFindLevel)==SQLITE_ROW ){
iAbsLevel = sqlite3_column_int64(pFindLevel, 0);
nSeg = sqlite3_column_int(pFindLevel, 1);
assert( nSeg>=2 );
}else{
nSeg = -1;
}
rc = sqlite3_reset(pFindLevel);
/* If the hint read from the %_stat table is not empty, check if the
** last entry in it specifies a relative level smaller than or equal
** to the level identified by the block above (if any). If so, this
** iteration of the loop will work on merging at the hinted level.
*/
if( rc==SQLITE_OK && hint.n ){
int nHint = hint.n;
sqlite3_int64 iHintAbsLevel = 0; /* Hint level */
int nHintSeg = 0; /* Hint number of segments */
rc = fts3IncrmergeHintPop(&hint, &iHintAbsLevel, &nHintSeg);
if( nSeg<0 || (iAbsLevel % nMod) >= (iHintAbsLevel % nMod) ){
iAbsLevel = iHintAbsLevel;
nSeg = nHintSeg;
bUseHint = 1;
bDirtyHint = 1;
}else{
/* This undoes the effect of the HintPop() above - so that no entry
** is removed from the hint blob. */
hint.n = nHint;
}
}
/* If nSeg is less that zero, then there is no level with at least
** nMin segments and no hint in the %_stat table. No work to do.
** Exit early in this case. */
if( nSeg<0 ) break;
/* Open a cursor to iterate through the contents of the oldest nSeg
** indexes of absolute level iAbsLevel. If this cursor is opened using
** the 'hint' parameters, it is possible that there are less than nSeg
** segments available in level iAbsLevel. In this case, no work is
** done on iAbsLevel - fall through to the next iteration of the loop
** to start work on some other level. */
memset(pWriter, 0, nAlloc);
pFilter->flags = FTS3_SEGMENT_REQUIRE_POS;
if( rc==SQLITE_OK ){
rc = fts3IncrmergeOutputIdx(p, iAbsLevel, &iIdx);
assert( bUseHint==1 || bUseHint==0 );
if( iIdx==0 || (bUseHint && iIdx==1) ){
int bIgnore = 0;
rc = fts3SegmentIsMaxLevel(p, iAbsLevel+1, &bIgnore);
if( bIgnore ){
pFilter->flags |= FTS3_SEGMENT_IGNORE_EMPTY;
}
}
}
if( rc==SQLITE_OK ){
rc = fts3IncrmergeCsr(p, iAbsLevel, nSeg, pCsr);
}
if( SQLITE_OK==rc && pCsr->nSegment==nSeg
&& SQLITE_OK==(rc = sqlite3Fts3SegReaderStart(p, pCsr, pFilter))
&& SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pCsr))
){
if( bUseHint && iIdx>0 ){
const char *zKey = pCsr->zTerm;
int nKey = pCsr->nTerm;
rc = fts3IncrmergeLoad(p, iAbsLevel, iIdx-1, zKey, nKey, pWriter);
}else{
rc = fts3IncrmergeWriter(p, iAbsLevel, iIdx, pCsr, pWriter);
}
if( rc==SQLITE_OK && pWriter->nLeafEst ){
fts3LogMerge(nSeg, iAbsLevel);
do {
rc = fts3IncrmergeAppend(p, pWriter, pCsr);
if( rc==SQLITE_OK ) rc = sqlite3Fts3SegReaderStep(p, pCsr);
if( pWriter->nWork>=nRem && rc==SQLITE_ROW ) rc = SQLITE_OK;
}while( rc==SQLITE_ROW );
/* Update or delete the input segments */
if( rc==SQLITE_OK ){
nRem -= (1 + pWriter->nWork);
rc = fts3IncrmergeChomp(p, iAbsLevel, pCsr, &nSeg);
if( nSeg!=0 ){
bDirtyHint = 1;
fts3IncrmergeHintPush(&hint, iAbsLevel, nSeg, &rc);
}
}
}
if( nSeg!=0 ){
pWriter->nLeafData = pWriter->nLeafData * -1;
}
fts3IncrmergeRelease(p, pWriter, &rc);
if( nSeg==0 && pWriter->bNoLeafData==0 ){
fts3PromoteSegments(p, iAbsLevel+1, pWriter->nLeafData);
}
}
sqlite3Fts3SegReaderFinish(pCsr);
}
/* Write the hint values into the %_stat table for the next incr-merger */
if( bDirtyHint && rc==SQLITE_OK ){
rc = fts3IncrmergeHintStore(p, &hint);
}
sqlite3_free(pWriter);
sqlite3_free(hint.a);
return rc;
}
/*
** Convert the text beginning at *pz into an integer and return
** its value. Advance *pz to point to the first character past
** the integer.
**
** This function used for parameters to merge= and incrmerge=
** commands.
*/
static int fts3Getint(const char **pz){
const char *z = *pz;
int i = 0;
while( (*z)>='0' && (*z)<='9' && i<214748363 ) i = 10*i + *(z++) - '0';
*pz = z;
return i;
}
/*
** Process statements of the form:
**
** INSERT INTO table(table) VALUES('merge=A,B');
**
** A and B are integers that decode to be the number of leaf pages
** written for the merge, and the minimum number of segments on a level
** before it will be selected for a merge, respectively.
*/
static int fts3DoIncrmerge(
Fts3Table *p, /* FTS3 table handle */
const char *zParam /* Nul-terminated string containing "A,B" */
){
int rc;
int nMin = (FTS3_MERGE_COUNT / 2);
int nMerge = 0;
const char *z = zParam;
/* Read the first integer value */
nMerge = fts3Getint(&z);
/* If the first integer value is followed by a ',', read the second
** integer value. */
if( z[0]==',' && z[1]!='\0' ){
z++;
nMin = fts3Getint(&z);
}
if( z[0]!='\0' || nMin<2 ){
rc = SQLITE_ERROR;
}else{
rc = SQLITE_OK;
if( !p->bHasStat ){
assert( p->bFts4==0 );
sqlite3Fts3CreateStatTable(&rc, p);
}
if( rc==SQLITE_OK ){
rc = sqlite3Fts3Incrmerge(p, nMerge, nMin);
}
sqlite3Fts3SegmentsClose(p);
}
return rc;
}
/*
** Process statements of the form:
**
** INSERT INTO table(table) VALUES('automerge=X');
**
** where X is an integer. X==0 means to turn automerge off. X!=0 means
** turn it on. The setting is persistent.
*/
static int fts3DoAutoincrmerge(
Fts3Table *p, /* FTS3 table handle */
const char *zParam /* Nul-terminated string containing boolean */
){
int rc = SQLITE_OK;
sqlite3_stmt *pStmt = 0;
p->nAutoincrmerge = fts3Getint(&zParam);
if( p->nAutoincrmerge==1 || p->nAutoincrmerge>FTS3_MERGE_COUNT ){
p->nAutoincrmerge = 8;
}
if( !p->bHasStat ){
assert( p->bFts4==0 );
sqlite3Fts3CreateStatTable(&rc, p);
if( rc ) return rc;
}
rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
if( rc ) return rc;
sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
sqlite3_bind_int(pStmt, 2, p->nAutoincrmerge);
sqlite3_step(pStmt);
rc = sqlite3_reset(pStmt);
return rc;
}
/*
** Return a 64-bit checksum for the FTS index entry specified by the
** arguments to this function.
*/
static u64 fts3ChecksumEntry(
const char *zTerm, /* Pointer to buffer containing term */
int nTerm, /* Size of zTerm in bytes */
int iLangid, /* Language id for current row */
int iIndex, /* Index (0..Fts3Table.nIndex-1) */
i64 iDocid, /* Docid for current row. */
int iCol, /* Column number */
int iPos /* Position */
){
int i;
u64 ret = (u64)iDocid;
ret += (ret<<3) + iLangid;
ret += (ret<<3) + iIndex;
ret += (ret<<3) + iCol;
ret += (ret<<3) + iPos;
for(i=0; i<nTerm; i++) ret += (ret<<3) + zTerm[i];
return ret;
}
/*
** Return a checksum of all entries in the FTS index that correspond to
** language id iLangid. The checksum is calculated by XORing the checksums
** of each individual entry (see fts3ChecksumEntry()) together.
**
** If successful, the checksum value is returned and *pRc set to SQLITE_OK.
** Otherwise, if an error occurs, *pRc is set to an SQLite error code. The
** return value is undefined in this case.
*/
static u64 fts3ChecksumIndex(
Fts3Table *p, /* FTS3 table handle */
int iLangid, /* Language id to return cksum for */
int iIndex, /* Index to cksum (0..p->nIndex-1) */
int *pRc /* OUT: Return code */
){
Fts3SegFilter filter;
Fts3MultiSegReader csr;
int rc;
u64 cksum = 0;
assert( *pRc==SQLITE_OK );
memset(&filter, 0, sizeof(filter));
memset(&csr, 0, sizeof(csr));
filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
filter.flags |= FTS3_SEGMENT_SCAN;
rc = sqlite3Fts3SegReaderCursor(
p, iLangid, iIndex, FTS3_SEGCURSOR_ALL, 0, 0, 0, 1,&csr
);
if( rc==SQLITE_OK ){
rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
}
if( rc==SQLITE_OK ){
while( SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, &csr)) ){
char *pCsr = csr.aDoclist;
char *pEnd = &pCsr[csr.nDoclist];
i64 iDocid = 0;
i64 iCol = 0;
i64 iPos = 0;
pCsr += sqlite3Fts3GetVarint(pCsr, &iDocid);
while( pCsr<pEnd ){
i64 iVal = 0;
pCsr += sqlite3Fts3GetVarint(pCsr, &iVal);
if( pCsr<pEnd ){
if( iVal==0 || iVal==1 ){
iCol = 0;
iPos = 0;
if( iVal ){
pCsr += sqlite3Fts3GetVarint(pCsr, &iCol);
}else{
pCsr += sqlite3Fts3GetVarint(pCsr, &iVal);
iDocid += iVal;
}
}else{
iPos += (iVal - 2);
cksum = cksum ^ fts3ChecksumEntry(
csr.zTerm, csr.nTerm, iLangid, iIndex, iDocid,
(int)iCol, (int)iPos
);
}
}
}
}
}
sqlite3Fts3SegReaderFinish(&csr);
*pRc = rc;
return cksum;
}
/*
** Check if the contents of the FTS index match the current contents of the
** content table. If no error occurs and the contents do match, set *pbOk
** to true and return SQLITE_OK. Or if the contents do not match, set *pbOk
** to false before returning.
**
** If an error occurs (e.g. an OOM or IO error), return an SQLite error
** code. The final value of *pbOk is undefined in this case.
*/
static int fts3IntegrityCheck(Fts3Table *p, int *pbOk){
int rc = SQLITE_OK; /* Return code */
u64 cksum1 = 0; /* Checksum based on FTS index contents */
u64 cksum2 = 0; /* Checksum based on %_content contents */
sqlite3_stmt *pAllLangid = 0; /* Statement to return all language-ids */
/* This block calculates the checksum according to the FTS index. */
rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
if( rc==SQLITE_OK ){
int rc2;
sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
sqlite3_bind_int(pAllLangid, 2, p->nIndex);
while( rc==SQLITE_OK && sqlite3_step(pAllLangid)==SQLITE_ROW ){
int iLangid = sqlite3_column_int(pAllLangid, 0);
int i;
for(i=0; i<p->nIndex; i++){
cksum1 = cksum1 ^ fts3ChecksumIndex(p, iLangid, i, &rc);
}
}
rc2 = sqlite3_reset(pAllLangid);
if( rc==SQLITE_OK ) rc = rc2;
}
/* This block calculates the checksum according to the %_content table */
if( rc==SQLITE_OK ){
sqlite3_tokenizer_module const *pModule = p->pTokenizer->pModule;
sqlite3_stmt *pStmt = 0;
char *zSql;
zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
if( !zSql ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
sqlite3_free(zSql);
}
while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
i64 iDocid = sqlite3_column_int64(pStmt, 0);
int iLang = langidFromSelect(p, pStmt);
int iCol;
for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
if( p->abNotindexed[iCol]==0 ){
const char *zText = (const char *)sqlite3_column_text(pStmt, iCol+1);
int nText = sqlite3_column_bytes(pStmt, iCol+1);
sqlite3_tokenizer_cursor *pT = 0;
rc = sqlite3Fts3OpenTokenizer(p->pTokenizer, iLang, zText, nText,&pT);
while( rc==SQLITE_OK ){
char const *zToken; /* Buffer containing token */
int nToken = 0; /* Number of bytes in token */
int iDum1 = 0, iDum2 = 0; /* Dummy variables */
int iPos = 0; /* Position of token in zText */
rc = pModule->xNext(pT, &zToken, &nToken, &iDum1, &iDum2, &iPos);
if( rc==SQLITE_OK ){
int i;
cksum2 = cksum2 ^ fts3ChecksumEntry(
zToken, nToken, iLang, 0, iDocid, iCol, iPos
);
for(i=1; i<p->nIndex; i++){
if( p->aIndex[i].nPrefix<=nToken ){
cksum2 = cksum2 ^ fts3ChecksumEntry(
zToken, p->aIndex[i].nPrefix, iLang, i, iDocid, iCol, iPos
);
}
}
}
}
if( pT ) pModule->xClose(pT);
if( rc==SQLITE_DONE ) rc = SQLITE_OK;
}
}
}
sqlite3_finalize(pStmt);
}
*pbOk = (cksum1==cksum2);
return rc;
}
/*
** Run the integrity-check. If no error occurs and the current contents of
** the FTS index are correct, return SQLITE_OK. Or, if the contents of the
** FTS index are incorrect, return SQLITE_CORRUPT_VTAB.
**
** Or, if an error (e.g. an OOM or IO error) occurs, return an SQLite
** error code.
**
** The integrity-check works as follows. For each token and indexed token
** prefix in the document set, a 64-bit checksum is calculated (by code
** in fts3ChecksumEntry()) based on the following:
**
** + The index number (0 for the main index, 1 for the first prefix
** index etc.),
** + The token (or token prefix) text itself,
** + The language-id of the row it appears in,
** + The docid of the row it appears in,
** + The column it appears in, and
** + The tokens position within that column.
**
** The checksums for all entries in the index are XORed together to create
** a single checksum for the entire index.
**
** The integrity-check code calculates the same checksum in two ways:
**
** 1. By scanning the contents of the FTS index, and
** 2. By scanning and tokenizing the content table.
**
** If the two checksums are identical, the integrity-check is deemed to have
** passed.
*/
static int fts3DoIntegrityCheck(
Fts3Table *p /* FTS3 table handle */
){
int rc;
int bOk = 0;
rc = fts3IntegrityCheck(p, &bOk);
if( rc==SQLITE_OK && bOk==0 ) rc = FTS_CORRUPT_VTAB;
return rc;
}
/*
** Handle a 'special' INSERT of the form:
**
** "INSERT INTO tbl(tbl) VALUES(<expr>)"
**
** Argument pVal contains the result of <expr>. Currently the only
** meaningful value to insert is the text 'optimize'.
*/
static int fts3SpecialInsert(Fts3Table *p, sqlite3_value *pVal){
int rc; /* Return Code */
const char *zVal = (const char *)sqlite3_value_text(pVal);
int nVal = sqlite3_value_bytes(pVal);
if( !zVal ){
return SQLITE_NOMEM;
}else if( nVal==8 && 0==sqlite3_strnicmp(zVal, "optimize", 8) ){
rc = fts3DoOptimize(p, 0);
}else if( nVal==7 && 0==sqlite3_strnicmp(zVal, "rebuild", 7) ){
rc = fts3DoRebuild(p);
}else if( nVal==15 && 0==sqlite3_strnicmp(zVal, "integrity-check", 15) ){
rc = fts3DoIntegrityCheck(p);
}else if( nVal>6 && 0==sqlite3_strnicmp(zVal, "merge=", 6) ){
rc = fts3DoIncrmerge(p, &zVal[6]);
}else if( nVal>10 && 0==sqlite3_strnicmp(zVal, "automerge=", 10) ){
rc = fts3DoAutoincrmerge(p, &zVal[10]);
#ifdef SQLITE_TEST
}else if( nVal>9 && 0==sqlite3_strnicmp(zVal, "nodesize=", 9) ){
p->nNodeSize = atoi(&zVal[9]);
rc = SQLITE_OK;
}else if( nVal>11 && 0==sqlite3_strnicmp(zVal, "maxpending=", 9) ){
p->nMaxPendingData = atoi(&zVal[11]);
rc = SQLITE_OK;
}else if( nVal>21 && 0==sqlite3_strnicmp(zVal, "test-no-incr-doclist=", 21) ){
p->bNoIncrDoclist = atoi(&zVal[21]);
rc = SQLITE_OK;
#endif
}else{
rc = SQLITE_ERROR;
}
return rc;
}
#ifndef SQLITE_DISABLE_FTS4_DEFERRED
/*
** Delete all cached deferred doclists. Deferred doclists are cached
** (allocated) by the sqlite3Fts3CacheDeferredDoclists() function.
*/
void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *pCsr){
Fts3DeferredToken *pDef;
for(pDef=pCsr->pDeferred; pDef; pDef=pDef->pNext){
fts3PendingListDelete(pDef->pList);
pDef->pList = 0;
}
}
/*
** Free all entries in the pCsr->pDeffered list. Entries are added to
** this list using sqlite3Fts3DeferToken().
*/
void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *pCsr){
Fts3DeferredToken *pDef;
Fts3DeferredToken *pNext;
for(pDef=pCsr->pDeferred; pDef; pDef=pNext){
pNext = pDef->pNext;
fts3PendingListDelete(pDef->pList);
sqlite3_free(pDef);
}
pCsr->pDeferred = 0;
}
/*
** Generate deferred-doclists for all tokens in the pCsr->pDeferred list
** based on the row that pCsr currently points to.
**
** A deferred-doclist is like any other doclist with position information
** included, except that it only contains entries for a single row of the
** table, not for all rows.
*/
int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *pCsr){
int rc = SQLITE_OK; /* Return code */
if( pCsr->pDeferred ){
int i; /* Used to iterate through table columns */
sqlite3_int64 iDocid; /* Docid of the row pCsr points to */
Fts3DeferredToken *pDef; /* Used to iterate through deferred tokens */
Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
sqlite3_tokenizer *pT = p->pTokenizer;
sqlite3_tokenizer_module const *pModule = pT->pModule;
assert( pCsr->isRequireSeek==0 );
iDocid = sqlite3_column_int64(pCsr->pStmt, 0);
for(i=0; i<p->nColumn && rc==SQLITE_OK; i++){
if( p->abNotindexed[i]==0 ){
const char *zText = (const char *)sqlite3_column_text(pCsr->pStmt, i+1);
sqlite3_tokenizer_cursor *pTC = 0;
rc = sqlite3Fts3OpenTokenizer(pT, pCsr->iLangid, zText, -1, &pTC);
while( rc==SQLITE_OK ){
char const *zToken; /* Buffer containing token */
int nToken = 0; /* Number of bytes in token */
int iDum1 = 0, iDum2 = 0; /* Dummy variables */
int iPos = 0; /* Position of token in zText */
rc = pModule->xNext(pTC, &zToken, &nToken, &iDum1, &iDum2, &iPos);
for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
Fts3PhraseToken *pPT = pDef->pToken;
if( (pDef->iCol>=p->nColumn || pDef->iCol==i)
&& (pPT->bFirst==0 || iPos==0)
&& (pPT->n==nToken || (pPT->isPrefix && pPT->n<nToken))
&& (0==memcmp(zToken, pPT->z, pPT->n))
){
fts3PendingListAppend(&pDef->pList, iDocid, i, iPos, &rc);
}
}
}
if( pTC ) pModule->xClose(pTC);
if( rc==SQLITE_DONE ) rc = SQLITE_OK;
}
}
for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
if( pDef->pList ){
rc = fts3PendingListAppendVarint(&pDef->pList, 0);
}
}
}
return rc;
}
int sqlite3Fts3DeferredTokenList(
Fts3DeferredToken *p,
char **ppData,
int *pnData
){
char *pRet;
int nSkip;
sqlite3_int64 dummy;
*ppData = 0;
*pnData = 0;
if( p->pList==0 ){
return SQLITE_OK;
}
pRet = (char *)sqlite3_malloc(p->pList->nData);
if( !pRet ) return SQLITE_NOMEM;
nSkip = sqlite3Fts3GetVarint(p->pList->aData, &dummy);
*pnData = p->pList->nData - nSkip;
*ppData = pRet;
memcpy(pRet, &p->pList->aData[nSkip], *pnData);
return SQLITE_OK;
}
/*
** Add an entry for token pToken to the pCsr->pDeferred list.
*/
int sqlite3Fts3DeferToken(
Fts3Cursor *pCsr, /* Fts3 table cursor */
Fts3PhraseToken *pToken, /* Token to defer */
int iCol /* Column that token must appear in (or -1) */
){
Fts3DeferredToken *pDeferred;
pDeferred = sqlite3_malloc(sizeof(*pDeferred));
if( !pDeferred ){
return SQLITE_NOMEM;
}
memset(pDeferred, 0, sizeof(*pDeferred));
pDeferred->pToken = pToken;
pDeferred->pNext = pCsr->pDeferred;
pDeferred->iCol = iCol;
pCsr->pDeferred = pDeferred;
assert( pToken->pDeferred==0 );
pToken->pDeferred = pDeferred;
return SQLITE_OK;
}
#endif
/*
** SQLite value pRowid contains the rowid of a row that may or may not be
** present in the FTS3 table. If it is, delete it and adjust the contents
** of subsiduary data structures accordingly.
*/
static int fts3DeleteByRowid(
Fts3Table *p,
sqlite3_value *pRowid,
int *pnChng, /* IN/OUT: Decrement if row is deleted */
u32 *aSzDel
){
int rc = SQLITE_OK; /* Return code */
int bFound = 0; /* True if *pRowid really is in the table */
fts3DeleteTerms(&rc, p, pRowid, aSzDel, &bFound);
if( bFound && rc==SQLITE_OK ){
int isEmpty = 0; /* Deleting *pRowid leaves the table empty */
rc = fts3IsEmpty(p, pRowid, &isEmpty);
if( rc==SQLITE_OK ){
if( isEmpty ){
/* Deleting this row means the whole table is empty. In this case
** delete the contents of all three tables and throw away any
** data in the pendingTerms hash table. */
rc = fts3DeleteAll(p, 1);
*pnChng = 0;
memset(aSzDel, 0, sizeof(u32) * (p->nColumn+1) * 2);
}else{
*pnChng = *pnChng - 1;
if( p->zContentTbl==0 ){
fts3SqlExec(&rc, p, SQL_DELETE_CONTENT, &pRowid);
}
if( p->bHasDocsize ){
fts3SqlExec(&rc, p, SQL_DELETE_DOCSIZE, &pRowid);
}
}
}
}
return rc;
}
/*
** This function does the work for the xUpdate method of FTS3 virtual
** tables. The schema of the virtual table being:
**
** CREATE TABLE <table name>(
** <user columns>,
** <table name> HIDDEN,
** docid HIDDEN,
** <langid> HIDDEN
** );
**
**
*/
int sqlite3Fts3UpdateMethod(
sqlite3_vtab *pVtab, /* FTS3 vtab object */
int nArg, /* Size of argument array */
sqlite3_value **apVal, /* Array of arguments */
sqlite_int64 *pRowid /* OUT: The affected (or effected) rowid */
){
Fts3Table *p = (Fts3Table *)pVtab;
int rc = SQLITE_OK; /* Return Code */
int isRemove = 0; /* True for an UPDATE or DELETE */
u32 *aSzIns = 0; /* Sizes of inserted documents */
u32 *aSzDel = 0; /* Sizes of deleted documents */
int nChng = 0; /* Net change in number of documents */
int bInsertDone = 0;
/* At this point it must be known if the %_stat table exists or not.
** So bHasStat may not be 2. */
assert( p->bHasStat==0 || p->bHasStat==1 );
assert( p->pSegments==0 );
assert(
nArg==1 /* DELETE operations */
|| nArg==(2 + p->nColumn + 3) /* INSERT or UPDATE operations */
);
/* Check for a "special" INSERT operation. One of the form:
**
** INSERT INTO xyz(xyz) VALUES('command');
*/
if( nArg>1
&& sqlite3_value_type(apVal[0])==SQLITE_NULL
&& sqlite3_value_type(apVal[p->nColumn+2])!=SQLITE_NULL
){
rc = fts3SpecialInsert(p, apVal[p->nColumn+2]);
goto update_out;
}
if( nArg>1 && sqlite3_value_int(apVal[2 + p->nColumn + 2])<0 ){
rc = SQLITE_CONSTRAINT;
goto update_out;
}
/* Allocate space to hold the change in document sizes */
aSzDel = sqlite3_malloc( sizeof(aSzDel[0])*(p->nColumn+1)*2 );
if( aSzDel==0 ){
rc = SQLITE_NOMEM;
goto update_out;
}
aSzIns = &aSzDel[p->nColumn+1];
memset(aSzDel, 0, sizeof(aSzDel[0])*(p->nColumn+1)*2);
rc = fts3Writelock(p);
if( rc!=SQLITE_OK ) goto update_out;
/* If this is an INSERT operation, or an UPDATE that modifies the rowid
** value, then this operation requires constraint handling.
**
** If the on-conflict mode is REPLACE, this means that the existing row
** should be deleted from the database before inserting the new row. Or,
** if the on-conflict mode is other than REPLACE, then this method must
** detect the conflict and return SQLITE_CONSTRAINT before beginning to
** modify the database file.
*/
if( nArg>1 && p->zContentTbl==0 ){
/* Find the value object that holds the new rowid value. */
sqlite3_value *pNewRowid = apVal[3+p->nColumn];
if( sqlite3_value_type(pNewRowid)==SQLITE_NULL ){
pNewRowid = apVal[1];
}
if( sqlite3_value_type(pNewRowid)!=SQLITE_NULL && (
sqlite3_value_type(apVal[0])==SQLITE_NULL
|| sqlite3_value_int64(apVal[0])!=sqlite3_value_int64(pNewRowid)
)){
/* The new rowid is not NULL (in this case the rowid will be
** automatically assigned and there is no chance of a conflict), and
** the statement is either an INSERT or an UPDATE that modifies the
** rowid column. So if the conflict mode is REPLACE, then delete any
** existing row with rowid=pNewRowid.
**
** Or, if the conflict mode is not REPLACE, insert the new record into
** the %_content table. If we hit the duplicate rowid constraint (or any
** other error) while doing so, return immediately.
**
** This branch may also run if pNewRowid contains a value that cannot
** be losslessly converted to an integer. In this case, the eventual
** call to fts3InsertData() (either just below or further on in this
** function) will return SQLITE_MISMATCH. If fts3DeleteByRowid is
** invoked, it will delete zero rows (since no row will have
** docid=$pNewRowid if $pNewRowid is not an integer value).
*/
if( sqlite3_vtab_on_conflict(p->db)==SQLITE_REPLACE ){
rc = fts3DeleteByRowid(p, pNewRowid, &nChng, aSzDel);
}else{
rc = fts3InsertData(p, apVal, pRowid);
bInsertDone = 1;
}
}
}
if( rc!=SQLITE_OK ){
goto update_out;
}
/* If this is a DELETE or UPDATE operation, remove the old record. */
if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER );
rc = fts3DeleteByRowid(p, apVal[0], &nChng, aSzDel);
isRemove = 1;
}
/* If this is an INSERT or UPDATE operation, insert the new record. */
if( nArg>1 && rc==SQLITE_OK ){
int iLangid = sqlite3_value_int(apVal[2 + p->nColumn + 2]);
if( bInsertDone==0 ){
rc = fts3InsertData(p, apVal, pRowid);
if( rc==SQLITE_CONSTRAINT && p->zContentTbl==0 ){
rc = FTS_CORRUPT_VTAB;
}
}
if( rc==SQLITE_OK && (!isRemove || *pRowid!=p->iPrevDocid ) ){
rc = fts3PendingTermsDocid(p, 0, iLangid, *pRowid);
}
if( rc==SQLITE_OK ){
assert( p->iPrevDocid==*pRowid );
rc = fts3InsertTerms(p, iLangid, apVal, aSzIns);
}
if( p->bHasDocsize ){
fts3InsertDocsize(&rc, p, aSzIns);
}
nChng++;
}
if( p->bFts4 ){
fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nChng);
}
update_out:
sqlite3_free(aSzDel);
sqlite3Fts3SegmentsClose(p);
return rc;
}
/*
** Flush any data in the pending-terms hash table to disk. If successful,
** merge all segments in the database (including the new segment, if
** there was any data to flush) into a single segment.
*/
int sqlite3Fts3Optimize(Fts3Table *p){
int rc;
rc = sqlite3_exec(p->db, "SAVEPOINT fts3", 0, 0, 0);
if( rc==SQLITE_OK ){
rc = fts3DoOptimize(p, 1);
if( rc==SQLITE_OK || rc==SQLITE_DONE ){
int rc2 = sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
if( rc2!=SQLITE_OK ) rc = rc2;
}else{
sqlite3_exec(p->db, "ROLLBACK TO fts3", 0, 0, 0);
sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
}
}
sqlite3Fts3SegmentsClose(p);
return rc;
}
#endif