SQLite

** @(#) $Id: analyze.c,v 1.52 2009/04/16 17:45:48 drh Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table for
** writing with cursor iStatCur. If the library was built with the
** SQLITE_ENABLE_STAT2 macro defined, then the sqlite_stat2 table is
** opened for writing using cursor (iStatCur+1)
**
** If the sqlite_stat1 tables does not previously exist, it is created.
** Similarly, if the sqlite_stat2 table does not exist and the library
** is compiled with SQLITE_ENABLE_STAT2 defined, it is created. 
**
** Argument zWhere may be a pointer to a buffer containing a table name,
** or it may be a NULL pointer. If it is not NULL, then all entries in
** the sqlite_stat1 and (if applicable) sqlite_stat2 tables associated
** with the named table are deleted. If zWhere==0, then code is generated
** to delete all stat table entries.
*/
static void openStatTable(
  Parse *pParse,          /* Parsing context */
  int iDb,                /* The database we are looking in */
  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
  const char *zWhere      /* Delete entries associated with this table */
){
  static struct {
    const char *zName;
    const char *zCols;
  } aTable[] = {
    { "sqlite_stat1", "tbl,idx,stat" },
#ifdef SQLITE_ENABLE_STAT2
    { "sqlite_stat2", "tbl,idx,sampleno,sample" },
#endif
  };

  int aRoot[] = {0, 0};
  int aCreateTbl[] = {0, 0};

  int i;
  sqlite3 *db = pParse->db;
  Db *pDb;
  Vdbe *v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;
  assert( sqlite3BtreeHoldsAllMutexes(db) );
  assert( sqlite3VdbeDb(v)==db );
  pDb = &db->aDb[iDb];

  for(i=0; i<ArraySize(aTable); i++){
    const char *zTab = aTable[i].zName;
    Table *pStat;
    if( (pStat = sqlite3FindTable(db, zTab, pDb->zName))==0 ){
      /* The sqlite_stat[12] table does not exist. Create it. Note that a 
      ** side-effect of the CREATE TABLE statement is to leave the rootpage 
      ** of the new table in register pParse->regRoot. This is important 
      ** because the OpenWrite opcode below will be needing it. */
      sqlite3NestedParse(pParse,
          "CREATE TABLE %Q.%s(%s)", pDb->zName, zTab, aTable[i].zCols
      );
      aRoot[i] = pParse->regRoot;
      aCreateTbl[i] = 1;
    }else{
      /* The table already exists. If zWhere is not NULL, delete all entries 
      ** associated with the table zWhere. If zWhere is NULL, delete the
      ** entire contents of the table. */
      aRoot[i] = pStat->tnum;
      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
      if( zWhere ){
        sqlite3NestedParse(pParse,
           "DELETE FROM %Q.%s WHERE tbl=%Q", pDb->zName, zTab, zWhere
        );
      }else{
        /* The sqlite_stat[12] table already exists.  Delete all rows. */
        sqlite3VdbeAddOp2(v, OP_Clear, aRoot[i], iDb);
      }
    }
  }

  /* Open the sqlite_stat[12] tables for writing. */
  for(i=0; i<ArraySize(aTable); i++){
    sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur+i, aRoot[i], iDb);
    sqlite3VdbeChangeP4(v, -1, (char *)3, P4_INT32);
    sqlite3VdbeChangeP5(v, aCreateTbl[i]);
  }
}

/*
** Generate code to do an analysis of all indices associated with
** a single table.
*/
static void analyzeOneTable(
  Parse *pParse,   /* Parser context */
  Table *pTab,     /* Table whose indices are to be analyzed */
  int iStatCur,    /* Index of VdbeCursor that writes the sqlite_stat1 table */
  int iMem         /* Available memory locations begin here */
){
  Index *pIdx;                 /* An index to being analyzed */
  int iIdxCur;                 /* Cursor open on index being analyzed */
  Vdbe *v;                     /* The virtual machine being built up */
  int i;                       /* Loop counter */
  int topOfLoop;               /* The top of the loop */
  int endOfLoop;               /* The end of the loop */
  int addr;                    /* The address of an instruction */
  int iDb;                     /* Index of database containing pTab */



  int regTabname = iMem++;     /* Register containing table name */
  int regIdxname = iMem++;     /* Register containing index name */
  int regSampleno = iMem++;    /* Register containing next sample number */
  int regCol = iMem++;         /* Content of a column analyzed table */



  int regRec = iMem++;         /* Register holding completed record */
  int regTemp = iMem++;        /* Temporary use register */
  int regRowid = iMem++;       /* Rowid for the inserted record */

#ifdef SQLITE_ENABLE_STAT2
  int regTemp2 = iMem++;       /* Temporary use register */
  int regSamplerecno = iMem++; /* Next sample index record number */
  int regRecno = iMem++;       /* Register next index record number */
  int regCount = iMem++;       /* Total number of records in table */
#endif

  v = sqlite3GetVdbe(pParse);
  if( v==0 || NEVER(pTab==0) || pTab->pIndex==0 ){
    /* Do no analysis for tables that have no indices */
    return;
  }
  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );

    /* Open a cursor to the index to be analyzed. */
    assert( iDb==sqlite3SchemaToIndex(pParse->db, pIdx->pSchema) );
    sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb,
        (char *)pKey, P4_KEYINFO_HANDOFF);
    VdbeComment((v, "%s", pIdx->zName));

    /* Populate the registers containing the table and index names. */
    if( pTab->pIndex==pIdx ){
      sqlite3VdbeAddOp4(v, OP_String8, 0, regTabname, 0, pTab->zName, 0);
    }
    sqlite3VdbeAddOp4(v, OP_String8, 0, regIdxname, 0, pIdx->zName, 0);

#ifdef SQLITE_ENABLE_STAT2
    /* If this iteration of the loop is generating code to analyze the
    ** first index in the pTab->pIndex list, then register regCount has
    ** not been populated. In this case populate it now.  */
    if( pTab->pIndex==pIdx ){
      sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regCount);

    }


    /* Zero the regSampleno and regRecno registers. */
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regSampleno);
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRecno);

    /* If there are less than INDEX_SAMPLES records in the index, then
    ** set the contents of regSampleRecno to integer value INDEX_SAMPLES.
    ** Otherwise, set it to zero. This is to ensure that if there are 
    ** less than the said number of entries in the index, no samples at
    ** all are collected.  */
    sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES, regSamplerecno);
    sqlite3VdbeAddOp3(v, OP_Lt, regSamplerecno, sqlite3VdbeCurrentAddr(v)+2,
        regCount);
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regSamplerecno);
#endif

    /* Memory cells are used as follows. All memory cell addresses are
    ** offset by iMem. That is, cell 0 below is actually cell iMem, cell
    ** 1 is cell 1+iMem, etc.
    **
    **    0:               The total number of rows in the table.
    **

    endOfLoop = sqlite3VdbeMakeLabel(v);
    sqlite3VdbeAddOp2(v, OP_Rewind, iIdxCur, endOfLoop);
    topOfLoop = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1);

    for(i=0; i<nCol; i++){
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regCol);
#ifdef SQLITE_ENABLE_STAT2
      if( i==0 ){

        /* Check if the record that cursor iIdxCur points to contains a
        ** value that should be stored in the sqlite_stat2 table. If so,
        ** store it.  */
        int ne = sqlite3VdbeAddOp3(v, OP_Ne, regRecno, 0, regSamplerecno);
        assert( regTabname+1==regIdxname 
             && regTabname+2==regSampleno
             && regTabname+3==regCol

        sqlite3VdbeAddOp3(v, OP_Subtract, regSampleno, regTemp2, regTemp2);
        sqlite3VdbeAddOp3(v, OP_Divide, regTemp2, regTemp, regTemp);
        sqlite3VdbeAddOp3(v, OP_Add, regSamplerecno, regTemp, regSamplerecno);

        sqlite3VdbeJumpHere(v, ne);
        sqlite3VdbeAddOp2(v, OP_AddImm, regRecno, 1);
      }
      assert( sqlite3VdbeCurrentAddr(v)==(topOfLoop+14+2*i) );
#else
      assert( sqlite3VdbeCurrentAddr(v)==(topOfLoop+2+2*i) );
#endif

      sqlite3VdbeAddOp3(v, OP_Ne, regCol, 0, iMem+nCol+i+1);

      /**** TODO:  add collating sequence *****/
      sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
    }
    sqlite3VdbeAddOp2(v, OP_Goto, 0, endOfLoop);
    for(i=0; i<nCol; i++){
#ifdef SQLITE_ENABLE_STAT2
      sqlite3VdbeJumpHere(v, topOfLoop+14+2*i);
#else
      sqlite3VdbeJumpHere(v, topOfLoop+2+2*i);
#endif
      sqlite3VdbeAddOp2(v, OP_AddImm, iMem+i+1, 1);
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, iMem+nCol+i+1);
    }

    /* End of the analysis loop. */
    sqlite3VdbeResolveLabel(v, endOfLoop);
    sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, topOfLoop);

    (void)sqlite3SafetyOff(db);
    rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
    (void)sqlite3SafetyOn(db);
    sqlite3DbFree(db, zSql);
  }

  /* Load the statistics from the sqlite_stat2 table. */
#ifdef SQLITE_ENABLE_STAT2
  if( rc==SQLITE_OK ){
    sqlite3_stmt *pStmt = 0;

    zSql = sqlite3MPrintf(db, 
        "SELECT idx,sampleno,sample FROM %Q.sqlite_stat2", sInfo.zDatabase
    );
    if( !zSql ){

        Index *pIdx = sqlite3FindIndex(db, zIndex, sInfo.zDatabase);
        if( pIdx ){
          int iSample = sqlite3_column_int(pStmt, 1);
          if( iSample<SQLITE_INDEX_SAMPLES && iSample>=0 ){
            int eType = sqlite3_column_type(pStmt, 2);

            if( pIdx->aSample==0 ){
              static const int nByte = sizeof(IndexSample)*SQLITE_INDEX_SAMPLES;
              pIdx->aSample = (IndexSample *)sqlite3DbMallocZero(db, nByte);


              if( pIdx->aSample==0 ){
                break;
              }
            }

            if( pIdx->aSample ){
              IndexSample *pSample = &pIdx->aSample[iSample];
              if( pSample->eType==SQLITE_TEXT || pSample->eType==SQLITE_BLOB ){
                sqlite3DbFree(db, pSample->u.z);
              }
              pSample->eType = eType;
              if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
                pSample->u.r = sqlite3_column_double(pStmt, 2);
              }else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
                const char *z = (const char *)(
                    (eType==SQLITE_BLOB) ?
                    sqlite3_column_blob(pStmt, 2):
                    sqlite3_column_text(pStmt, 2)
                );
                int n = sqlite3_column_bytes(pStmt, 2);
                if( n>24 ){
                  n = 24;
                }
                pSample->nByte = n;
                pSample->u.z = sqlite3DbMallocRaw(db, n);
                if( pSample->u.z ){
                  memcpy(pSample->u.z, z, n);
                }else{
                  break;
                }
              }
            }
          }
        }
      }
      rc = sqlite3_finalize(pStmt);
    }
    (void)sqlite3SafetyOn(db);
  }
#endif

  if( rc==SQLITE_NOMEM ){
    db->mallocFailed = 1;
  }
  return rc;
}


#endif /* SQLITE_OMIT_ANALYZE */

const void *sqlite3ValueText(sqlite3_value*, u8);
int sqlite3ValueBytes(sqlite3_value*, u8);
void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8, 
                        void(*)(void*));
void sqlite3ValueFree(sqlite3_value*);
sqlite3_value *sqlite3ValueNew(sqlite3 *);
char *sqlite3Utf16to8(sqlite3 *, const void*, int);
#ifdef SQLITE_ENABLE_STAT2
char *sqlite3Utf8to16(sqlite3 *, int, char *, int, int *);
#endif
int sqlite3ValueFromExpr(sqlite3 *, Expr *, u8, u8, sqlite3_value **);
void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);
#ifndef SQLITE_AMALGAMATION
extern const unsigned char sqlite3UpperToLower[];
extern const unsigned char sqlite3CtypeMap[];
extern SQLITE_WSD struct Sqlite3Config sqlite3Config;
extern SQLITE_WSD FuncDefHash sqlite3GlobalFunctions;

#endif

#ifdef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
  Tcl_SetVar2(interp, "sqlite_options", "schema_version", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "schema_version", "1", TCL_GLOBAL_ONLY);
#endif

#ifdef SQLITE_ENABLE_STAT2
  Tcl_SetVar2(interp, "sqlite_options", "stat2", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "stat2", "0", TCL_GLOBAL_ONLY);
#endif

#if !defined(SQLITE_ENABLE_LOCKING_STYLE)
#  if defined(__APPLE__)
#    define SQLITE_ENABLE_LOCKING_STYLE 1
#  else
#    define SQLITE_ENABLE_LOCKING_STYLE 0
#  endif

** is set to the length of the returned string in bytes. The call should
** arrange to call sqlite3DbFree() on the returned pointer when it is
** no longer required.
** 
** If a malloc failure occurs, NULL is returned and the db.mallocFailed
** flag set.
*/
#ifdef SQLITE_ENABLE_STAT2
char *sqlite3Utf8to16(sqlite3 *db, int enc, char *z, int n, int *pnOut){
  Mem m;
  memset(&m, 0, sizeof(m));
  m.db = db;
  sqlite3VdbeMemSetStr(&m, z, n, SQLITE_UTF8, SQLITE_STATIC);
  if( sqlite3VdbeMemTranslate(&m, enc) ){
    assert( db->mallocFailed );
    return 0;
  }
  assert( m.z==m.zMalloc );
  *pnOut = m.n;
  return m.z;
}
#endif

/*
** pZ is a UTF-16 encoded unicode string at least nChar characters long.
** Return the number of bytes in the first nChar unicode characters
** in pZ.  nChar must be non-negative.
*/
int sqlite3Utf16ByteLen(const void *zIn, int nChar){

** but smaller than the value of the second. And so on.
**
** If successful, this function determines which of the regions value 
** pVal lies in, sets *piRegion to the region index and returns SQLITE_OK.
** Or, if an OOM occurs while converting text values between encodings,
** SQLITE_NOMEM is returned.
*/
#ifdef SQLITE_ENABLE_STAT2
static int whereRangeRegion(
  Parse *pParse,              /* Database connection */
  Index *pIdx,                /* Index to consider domain of */
  sqlite3_value *pVal,        /* Value to consider */
  int *piRegion               /* OUT: Region of domain in which value lies */
){
  if( pVal ){

      }
    }

    *piRegion = i;
  }
  return SQLITE_OK;
}
#endif   /* #ifdef SQLITE_ENABLE_STAT2 */

/*
** This function is used to estimate the number of rows that will be visited
** by scanning an index for a range of values. The range may have an upper
** bound, a lower bound, or both. The WHERE clause terms that set the upper
** and lower bounds are represented by pLower and pUpper respectively. For
** example, assuming that index p is on t1(a):

  Parse *pParse,
  Index *p, 
  int nEq, 
  WhereTerm *pLower, 
  WhereTerm *pUpper,
  int *piEst                      /* OUT: Return value */
){
  int rc = SQLITE_OK;

#ifdef SQLITE_ENABLE_STAT2
  sqlite3 *db = pParse->db;
  sqlite3_value *pLowerVal = 0;
  sqlite3_value *pUpperVal = 0;


  if( nEq==0 && p->aSample ){
    int iEst;
    int iUpper = SQLITE_INDEX_SAMPLES;
    int iLower = 0;
    u8 aff = p->pTable->aCol[0].affinity;
    if( pLower ){

    else if( iEst<1 ) iEst = 1;

    sqlite3ValueFree(pLowerVal);
    sqlite3ValueFree(pUpperVal);
    *piEst = iEst;
    return rc;
  }

fallback:
#endif
  assert( pLower || pUpper );
  *piEst = (SQLITE_INDEX_SAMPLES-1) / ((pLower&&pUpper)?9:3);
  return rc;
}


/*

#***********************************************************************
#
# $Id: analyze.test,v 1.9 2008/08/11 18:44:58 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !stat2 {
  finish_test
  return
}

proc eqp sql {
  uplevel execsql [list "EXPLAIN QUERY PLAN $sql"]
}

do_test analyze2-1.1 {
  execsql { CREATE TABLE t1(x PRIMARY KEY) }
  for {set i 0} {$i < 1000} {incr i} {
    execsql { INSERT INTO t1 VALUES($i) }
  }
  execsql { 
    ANALYZE;
    SELECT * FROM sqlite_stat2;
  }
} [list t1 sqlite_autoindex_t1_1 0 0   \
        t1 sqlite_autoindex_t1_1 1 111 \
        t1 sqlite_autoindex_t1_1 2 222 \
        t1 sqlite_autoindex_t1_1 3 333 \
        t1 sqlite_autoindex_t1_1 4 444 \
        t1 sqlite_autoindex_t1_1 5 555 \
        t1 sqlite_autoindex_t1_1 6 666 \
        t1 sqlite_autoindex_t1_1 7 777 \
        t1 sqlite_autoindex_t1_1 8 888 \
        t1 sqlite_autoindex_t1_1 9 999 \
]

do_test analyze2-1.2 {
  execsql {
    DELETE FROM t1 WHERe x>9;
    ANALYZE;
    SELECT tbl, idx, group_concat(sample, ' ') FROM sqlite_stat2;
  }
} {t1 sqlite_autoindex_t1_1 {0 1 2 3 4 5 6 7 8 9}}

do_test analyze2-1.3 {
  execsql {
    DELETE FROM t1 WHERE x>5;
    ANALYZE;
    SELECT * FROM sqlite_stat2;
  }
} {}

do_test analyze2-1.4 {
  execsql {
    DELETE FROM t1;
    ANALYZE;
    SELECT * FROM sqlite_stat2;
  }
} {}





do_test analyze2-1.1 {
  execsql { 
    DROP TABLE t1;
    CREATE TABLE t1(x, y);
    CREATE INDEX t1_x ON t1(x);
    CREATE INDEX t1_y ON t1(y);
  }

      DROP TABLE tx;
    }
    ifcapable view {
      execsql {
        DROP TABLE v1chng;
      }
    }
  }
  ifcapable stat2 {
    set stat2 "sqlite_stat2 "
  } else {
    set stat2 ""
  }
  do_test auth-5.2 {
    execsql {
      SELECT name FROM (
        SELECT * FROM sqlite_master UNION ALL SELECT * FROM sqlite_temp_master)
      WHERE type='table'
      ORDER BY name
    }
  } "sqlite_stat1 ${stat2}t1 t2 t3 t4"
}

# Ticket #3944
#
ifcapable trigger {
  do_test auth-5.3.1 {
    execsql {