SEGDIR_SET_STMT,
  SEGDIR_SELECT_LEVEL_STMT,
  SEGDIR_SPAN_STMT,
  SEGDIR_DELETE_STMT,
  SEGDIR_SELECT_SEGMENT_STMT,
  SEGDIR_SELECT_ALL_STMT,
  SEGDIR_DELETE_ALL_STMT,


  MAX_STMT                     /* Always at end! */
} fulltext_statement;

/* These must exactly match the enum above. */
/* TODO(shess): Is there some risk that a statement will be used in two
** cursors at once, e.g.  if a query joins a virtual table to itself?
................................................................................
  /* SEGDIR_SELECT_SEGMENT */
  "select start_block, leaves_end_block, root from %_segdir "
  " where level = ? and idx = ?",
  /* SEGDIR_SELECT_ALL */
  "select start_block, leaves_end_block, root from %_segdir "
  " order by level desc, idx asc",
  /* SEGDIR_DELETE_ALL */ "delete from %_segdir",

};

/*
** A connection to a fulltext index is an instance of the following
** structure.  The xCreate and xConnect methods create an instance
** of this structure and xDestroy and xDisconnect free that instance.
** All other methods receive a pointer to the structure as one of their
................................................................................
*/
static int sql_single_step(sqlite3_stmt *s){
  int rc = sqlite3_step(s);
  return (rc==SQLITE_DONE) ? SQLITE_OK : rc;
}

/* Like sql_get_statement(), but for special replicated LEAF_SELECT
** statements.

*/
/* TODO(shess) Write version for generic statements and then share
** that between the cached-statement functions.
*/
static int sql_get_leaf_statement(fulltext_vtab *v, int idx,
                                  sqlite3_stmt **ppStmt){
  assert( idx>=0 && idx<MERGE_COUNT );


  if( v->pLeafSelectStmts[idx]==NULL ){
    int rc = sql_prepare(v->db, v->zDb, v->zName, &v->pLeafSelectStmts[idx],
                         LEAF_SELECT);
    if( rc!=SQLITE_OK ) return rc;
  }else{
    int rc = sqlite3_reset(v->pLeafSelectStmts[idx]);
    if( rc!=SQLITE_OK ) return rc;
  }
................................................................................
  if( rc!=SQLITE_OK ) return rc;

  rc = sql_get_statement(v, BLOCK_DELETE_ALL_STMT, &s);
  if( rc!=SQLITE_OK ) return rc;

  return sql_single_step(s);
}
































/* TODO(shess) clearPendingTerms() is far down the file because
** writeZeroSegment() is far down the file because LeafWriter is far
** down the file.  Consider refactoring the code to move the non-vtab
** code above the vtab code so that we don't need this forward
** reference.
*/
................................................................................
** this case.  Probably a brittle assumption.
*/
static int leavesReaderReset(LeavesReader *pReader){
  return sqlite3_reset(pReader->pStmt);
}

static void leavesReaderDestroy(LeavesReader *pReader){






  leafReaderDestroy(&pReader->leafReader);
  dataBufferDestroy(&pReader->rootData);
  SCRAMBLE(pReader);
}

/* Initialize pReader with the given root data (if iStartBlockid==0
** the leaf data was entirely contained in the root), or from the
................................................................................
    snippetAllOffsets(pCursor);
    snippetOffsetText(&pCursor->snippet);
    sqlite3_result_text(pContext,
                        pCursor->snippet.zOffset, pCursor->snippet.nOffset,
                        SQLITE_STATIC);
  }
}
























































































































































































































































































#ifdef SQLITE_TEST
/* Generate an error of the form "<prefix>: <msg>".  If msg is NULL,
** pull the error from the context's db handle.
*/
static void generateError(sqlite3_context *pContext,
                          const char *prefix, const char *msg){
................................................................................
){
  if( strcmp(zName,"snippet")==0 ){
    *pxFunc = snippetFunc;
    return 1;
  }else if( strcmp(zName,"offsets")==0 ){
    *pxFunc = snippetOffsetsFunc;
    return 1;



#ifdef SQLITE_TEST
    /* NOTE(shess): These functions are present only for testing
    ** purposes.  No particular effort is made to optimize their
    ** execution or how they build their results.
    */
  }else if( strcmp(zName,"dump_terms")==0 ){
    /* fprintf(stderr, "Found dump_terms\n"); */
................................................................................
  ** the two scalar functions. If this is successful, register the
  ** module with sqlite.
  */
  if( SQLITE_OK==rc 
   && SQLITE_OK==(rc = sqlite3Fts2InitHashTable(db, pHash, "fts2_tokenizer"))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", -1))

#ifdef SQLITE_TEST
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_terms", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_doclist", -1))
#endif
  ){
    return sqlite3_create_module_v2(
        db, "fts2", &fts2Module, (void *)pHash, hashDestroy

  SEGDIR_SET_STMT,
  SEGDIR_SELECT_LEVEL_STMT,
  SEGDIR_SPAN_STMT,
  SEGDIR_DELETE_STMT,
  SEGDIR_SELECT_SEGMENT_STMT,
  SEGDIR_SELECT_ALL_STMT,
  SEGDIR_DELETE_ALL_STMT,
  SEGDIR_COUNT_STMT,

  MAX_STMT                     /* Always at end! */
} fulltext_statement;

/* These must exactly match the enum above. */
/* TODO(shess): Is there some risk that a statement will be used in two
** cursors at once, e.g.  if a query joins a virtual table to itself?
................................................................................
  /* SEGDIR_SELECT_SEGMENT */
  "select start_block, leaves_end_block, root from %_segdir "
  " where level = ? and idx = ?",
  /* SEGDIR_SELECT_ALL */
  "select start_block, leaves_end_block, root from %_segdir "
  " order by level desc, idx asc",
  /* SEGDIR_DELETE_ALL */ "delete from %_segdir",
  /* SEGDIR_COUNT */ "select count(*), ifnull(max(level),0) from %_segdir",
};

/*
** A connection to a fulltext index is an instance of the following
** structure.  The xCreate and xConnect methods create an instance
** of this structure and xDestroy and xDisconnect free that instance.
** All other methods receive a pointer to the structure as one of their
................................................................................
*/
static int sql_single_step(sqlite3_stmt *s){
  int rc = sqlite3_step(s);
  return (rc==SQLITE_DONE) ? SQLITE_OK : rc;
}

/* Like sql_get_statement(), but for special replicated LEAF_SELECT
** statements.  idx -1 is a special case for an uncached version of
** the statement (used in the optimize implementation).
*/
/* TODO(shess) Write version for generic statements and then share
** that between the cached-statement functions.
*/
static int sql_get_leaf_statement(fulltext_vtab *v, int idx,
                                  sqlite3_stmt **ppStmt){
  assert( idx>=-1 && idx<MERGE_COUNT );
  if( idx==-1 ){
    return sql_prepare(v->db, v->zDb, v->zName, ppStmt, LEAF_SELECT);
  }else if( v->pLeafSelectStmts[idx]==NULL ){
    int rc = sql_prepare(v->db, v->zDb, v->zName, &v->pLeafSelectStmts[idx],
                         LEAF_SELECT);
    if( rc!=SQLITE_OK ) return rc;
  }else{
    int rc = sqlite3_reset(v->pLeafSelectStmts[idx]);
    if( rc!=SQLITE_OK ) return rc;
  }
................................................................................
  if( rc!=SQLITE_OK ) return rc;

  rc = sql_get_statement(v, BLOCK_DELETE_ALL_STMT, &s);
  if( rc!=SQLITE_OK ) return rc;

  return sql_single_step(s);
}

/* Returns SQLITE_OK with *pnSegments set to the number of entries in
** %_segdir and *piMaxLevel set to the highest level which has a
** segment.  Otherwise returns the SQLite error which caused failure.
*/
static int segdir_count(fulltext_vtab *v, int *pnSegments, int *piMaxLevel){
  sqlite3_stmt *s;
  int rc = sql_get_statement(v, SEGDIR_COUNT_STMT, &s);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3_step(s);
  /* TODO(shess): This case should not be possible?  Should stronger
  ** measures be taken if it happens?
  */
  if( rc==SQLITE_DONE ){
    *pnSegments = 0;
    *piMaxLevel = 0;
    return SQLITE_OK;
  }
  if( rc!=SQLITE_ROW ) return rc;

  *pnSegments = sqlite3_column_int(s, 0);
  *piMaxLevel = sqlite3_column_int(s, 1);

  /* We expect only one row.  We must execute another sqlite3_step()
   * to complete the iteration; otherwise the table will remain locked. */
  rc = sqlite3_step(s);
  if( rc==SQLITE_DONE ) return SQLITE_OK;
  if( rc==SQLITE_ROW ) return SQLITE_ERROR;
  return rc;
}

/* TODO(shess) clearPendingTerms() is far down the file because
** writeZeroSegment() is far down the file because LeafWriter is far
** down the file.  Consider refactoring the code to move the non-vtab
** code above the vtab code so that we don't need this forward
** reference.
*/
................................................................................
** this case.  Probably a brittle assumption.
*/
static int leavesReaderReset(LeavesReader *pReader){
  return sqlite3_reset(pReader->pStmt);
}

static void leavesReaderDestroy(LeavesReader *pReader){
  /* If idx is -1, that means we're using a non-cached statement
  ** handle in the optimize() case, so we need to release it.
  */
  if( pReader->pStmt!=NULL && pReader->idx==-1 ){
    sqlite3_finalize(pReader->pStmt);
  }
  leafReaderDestroy(&pReader->leafReader);
  dataBufferDestroy(&pReader->rootData);
  SCRAMBLE(pReader);
}

/* Initialize pReader with the given root data (if iStartBlockid==0
** the leaf data was entirely contained in the root), or from the
................................................................................
    snippetAllOffsets(pCursor);
    snippetOffsetText(&pCursor->snippet);
    sqlite3_result_text(pContext,
                        pCursor->snippet.zOffset, pCursor->snippet.nOffset,
                        SQLITE_STATIC);
  }
}

/* OptLeavesReader is nearly identical to LeavesReader, except that
** where LeavesReader is geared towards the merging of complete
** segment levels (with exactly MERGE_COUNT segments), OptLeavesReader
** is geared towards implementation of the optimize() function, and
** can merge all segments simultaneously.  This version may be
** somewhat less efficient than LeavesReader because it merges into an
** accumulator rather than doing an N-way merge, but since segment
** size grows exponentially (so segment count logrithmically) this is
** probably not an immediate problem.
*/
/* TODO(shess): Prove that assertion, or extend the merge code to
** merge tree fashion (like the prefix-searching code does).
*/
/* TODO(shess): OptLeavesReader and LeavesReader could probably be
** merged with little or no loss of performance for LeavesReader.  The
** merged code would need to handle >MERGE_COUNT segments, and would
** also need to be able to optionally optimize away deletes.
*/
typedef struct OptLeavesReader {
  /* Segment number, to order readers by age. */
  int segment;
  LeavesReader reader;
} OptLeavesReader;

static int optLeavesReaderAtEnd(OptLeavesReader *pReader){
  return leavesReaderAtEnd(&pReader->reader);
}
static int optLeavesReaderTermBytes(OptLeavesReader *pReader){
  return leavesReaderTermBytes(&pReader->reader);
}
static const char *optLeavesReaderData(OptLeavesReader *pReader){
  return leavesReaderData(&pReader->reader);
}
static int optLeavesReaderDataBytes(OptLeavesReader *pReader){
  return leavesReaderDataBytes(&pReader->reader);
}
static const char *optLeavesReaderTerm(OptLeavesReader *pReader){
  return leavesReaderTerm(&pReader->reader);
}
static int optLeavesReaderStep(fulltext_vtab *v, OptLeavesReader *pReader){
  return leavesReaderStep(v, &pReader->reader);
}
static int optLeavesReaderTermCmp(OptLeavesReader *lr1, OptLeavesReader *lr2){
  return leavesReaderTermCmp(&lr1->reader, &lr2->reader);
}
/* Order by term ascending, segment ascending (oldest to newest), with
** exhausted readers to the end.
*/
static int optLeavesReaderCmp(OptLeavesReader *lr1, OptLeavesReader *lr2){
  int c = optLeavesReaderTermCmp(lr1, lr2);
  if( c!=0 ) return c;
  return lr1->segment-lr2->segment;
}
/* Bubble pLr[0] to appropriate place in pLr[1..nLr-1].  Assumes that
** pLr[1..nLr-1] is already sorted.
*/
static void optLeavesReaderReorder(OptLeavesReader *pLr, int nLr){
  while( nLr>1 && optLeavesReaderCmp(pLr, pLr+1)>0 ){
    OptLeavesReader tmp = pLr[0];
    pLr[0] = pLr[1];
    pLr[1] = tmp;
    nLr--;
    pLr++;
  }
}

/* optimize() helper function.  Put the readers in order and iterate
** through them, merging doclists for matching terms into pWriter.
** Returns SQLITE_OK on success, or the SQLite error code which
** prevented success.
*/
static int optimizeInternal(fulltext_vtab *v,
                            OptLeavesReader *readers, int nReaders,
                            LeafWriter *pWriter){
  int i, rc = SQLITE_OK;
  DataBuffer doclist, merged, tmp;

  /* Order the readers. */
  i = nReaders;
  while( i-- > 0 ){
    optLeavesReaderReorder(&readers[i], nReaders-i);
  }

  dataBufferInit(&doclist, LEAF_MAX);
  dataBufferInit(&merged, LEAF_MAX);

  /* Exhausted readers bubble to the end, so when the first reader is
  ** at eof, all are at eof.
  */
  while( !optLeavesReaderAtEnd(&readers[0]) ){

    /* Figure out how many readers share the next term. */
    for(i=1; i<nReaders && !optLeavesReaderAtEnd(&readers[i]); i++){
      if( 0!=optLeavesReaderTermCmp(&readers[0], &readers[i]) ) break;
    }

    /* Special-case for no merge. */
    if( i==1 ){
      /* Trim deletions from the doclist. */
      dataBufferReset(&merged);
      docListTrim(DL_DEFAULT,
                  optLeavesReaderData(&readers[0]),
                  optLeavesReaderDataBytes(&readers[0]),
                  -1, DL_DEFAULT, &merged);
    }else{
      DLReader dlReaders[MERGE_COUNT];
      int iReader, nReaders;

      /* Prime the pipeline with the first reader's doclist.  After
      ** one pass index 0 will reference the accumulated doclist.
      */
      dlrInit(&dlReaders[0], DL_DEFAULT,
              optLeavesReaderData(&readers[0]),
              optLeavesReaderDataBytes(&readers[0]));
      iReader = 1;

      assert( iReader<i );  /* Must execute the loop at least once. */
      while( iReader<i ){
        /* Merge 16 inputs per pass. */
        for( nReaders=1; iReader<i && nReaders<MERGE_COUNT;
             iReader++, nReaders++ ){
          dlrInit(&dlReaders[nReaders], DL_DEFAULT,
                  optLeavesReaderData(&readers[iReader]),
                  optLeavesReaderDataBytes(&readers[iReader]));
        }

        /* Merge doclists and swap result into accumulator. */
        dataBufferReset(&merged);
        docListMerge(&merged, dlReaders, nReaders);
        tmp = merged;
        merged = doclist;
        doclist = tmp;

        while( nReaders-- > 0 ){
          dlrDestroy(&dlReaders[nReaders]);
        }

        /* Accumulated doclist to reader 0 for next pass. */
        dlrInit(&dlReaders[0], DL_DEFAULT, doclist.pData, doclist.nData);
      }

      /* Destroy reader that was left in the pipeline. */
      dlrDestroy(&dlReaders[0]);

      /* Trim deletions from the doclist. */
      dataBufferReset(&merged);
      docListTrim(DL_DEFAULT, doclist.pData, doclist.nData,
                  -1, DL_DEFAULT, &merged);
    }

    /* Only pass doclists with hits (skip if all hits deleted). */
    if( merged.nData>0 ){
      rc = leafWriterStep(v, pWriter,
                          optLeavesReaderTerm(&readers[0]),
                          optLeavesReaderTermBytes(&readers[0]),
                          merged.pData, merged.nData);
      if( rc!=SQLITE_OK ) goto err;
    }

    /* Step merged readers to next term and reorder. */
    while( i-- > 0 ){
      rc = optLeavesReaderStep(v, &readers[i]);
      if( rc!=SQLITE_OK ) goto err;

      optLeavesReaderReorder(&readers[i], nReaders-i);
    }
  }

 err:
  dataBufferDestroy(&doclist);
  dataBufferDestroy(&merged);
  return rc;
}

/* Implement optimize() function for FTS3.  optimize(t) merges all
** segments in the fts index into a single segment.  't' is the magic
** table-named column.
*/
static void optimizeFunc(sqlite3_context *pContext,
                         int argc, sqlite3_value **argv){
  fulltext_cursor *pCursor;
  if( argc>1 ){
    sqlite3_result_error(pContext, "excess arguments to optimize()",-1);
  }else if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
            sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
    sqlite3_result_error(pContext, "illegal first argument to optimize",-1);
  }else{
    fulltext_vtab *v;
    int i, rc, iMaxLevel;
    OptLeavesReader *readers;
    int nReaders;
    LeafWriter writer;
    sqlite3_stmt *s;

    memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
    v = cursor_vtab(pCursor);

    /* Flush any buffered updates before optimizing. */
    rc = flushPendingTerms(v);
    if( rc!=SQLITE_OK ) goto err;

    rc = segdir_count(v, &nReaders, &iMaxLevel);
    if( rc!=SQLITE_OK ) goto err;
    if( nReaders==0 || nReaders==1 ){
      sqlite3_result_text(pContext, "Index already optimal", -1,
                          SQLITE_STATIC);
      return;
    }

    rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
    if( rc!=SQLITE_OK ) goto err;

    readers = sqlite3_malloc(nReaders*sizeof(readers[0]));
    if( readers==NULL ) goto err;

    /* Note that there will already be a segment at this position
    ** until we call segdir_delete() on iMaxLevel.
    */
    leafWriterInit(iMaxLevel, 0, &writer);

    i = 0;
    while( (rc = sqlite3_step(s))==SQLITE_ROW ){
      sqlite_int64 iStart = sqlite3_column_int64(s, 0);
      sqlite_int64 iEnd = sqlite3_column_int64(s, 1);
      const char *pRootData = sqlite3_column_blob(s, 2);
      int nRootData = sqlite3_column_bytes(s, 2);

      assert( i<nReaders );
      rc = leavesReaderInit(v, -1, iStart, iEnd, pRootData, nRootData,
                            &readers[i].reader);
      if( rc!=SQLITE_OK ) break;

      readers[i].segment = i;
      i++;
    }

    /* If we managed to succesfully read them all, optimize them. */
    if( rc==SQLITE_DONE ){
      assert( i==nReaders );
      rc = optimizeInternal(v, readers, nReaders, &writer);
    }

    while( i-- > 0 ){
      leavesReaderDestroy(&readers[i].reader);
    }
    sqlite3_free(readers);

    /* If we've successfully gotten to here, delete the old segments
    ** and flush the interior structure of the new segment.
    */
    if( rc==SQLITE_OK ){
      for( i=0; i<=iMaxLevel; i++ ){
        rc = segdir_delete(v, i);
        if( rc!=SQLITE_OK ) break;
      }

      if( rc==SQLITE_OK ) rc = leafWriterFinalize(v, &writer);
    }

    leafWriterDestroy(&writer);

    if( rc!=SQLITE_OK ) goto err;

    sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
    return;

    /* TODO(shess): Error-handling needs to be improved along the
    ** lines of the dump_ functions.
    */
 err:
    {
      char buf[512];
      sqlite3_snprintf(sizeof(buf), buf, "Error in optimize: %s",
                       sqlite3_errmsg(sqlite3_context_db_handle(pContext)));
      sqlite3_result_error(pContext, buf, -1);
    }
  }
}

#ifdef SQLITE_TEST
/* Generate an error of the form "<prefix>: <msg>".  If msg is NULL,
** pull the error from the context's db handle.
*/
static void generateError(sqlite3_context *pContext,
                          const char *prefix, const char *msg){
................................................................................
){
  if( strcmp(zName,"snippet")==0 ){
    *pxFunc = snippetFunc;
    return 1;
  }else if( strcmp(zName,"offsets")==0 ){
    *pxFunc = snippetOffsetsFunc;
    return 1;
  }else if( strcmp(zName,"optimize")==0 ){
    *pxFunc = optimizeFunc;
    return 1;
#ifdef SQLITE_TEST
    /* NOTE(shess): These functions are present only for testing
    ** purposes.  No particular effort is made to optimize their
    ** execution or how they build their results.
    */
  }else if( strcmp(zName,"dump_terms")==0 ){
    /* fprintf(stderr, "Found dump_terms\n"); */
................................................................................
  ** the two scalar functions. If this is successful, register the
  ** module with sqlite.
  */
  if( SQLITE_OK==rc 
   && SQLITE_OK==(rc = sqlite3Fts2InitHashTable(db, pHash, "fts2_tokenizer"))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", -1))
#ifdef SQLITE_TEST
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_terms", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "dump_doclist", -1))
#endif
  ){
    return sqlite3_create_module_v2(
        db, "fts2", &fts2Module, (void *)pHash, hashDestroy

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#*************************************************************************
# This file implements regression tests for SQLite library.  The focus
# of this script is testing the FTS2 module's optimize() function.
#
# $Id: fts2q.test,v 1.1 2008/07/22 23:41:26 shess Exp $
#

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

# If SQLITE_ENABLE_FTS2 is not defined, omit this file.
ifcapable !fts2 {
................................................................................

check_terms   fts2q-1.2   0 0 {a is test this}
check_doclist fts2q-1.2.1 0 0 a {[1 0[2]]}
check_doclist fts2q-1.2.2 0 0 is {[1 0[1]]}
check_doclist fts2q-1.2.3 0 0 test {[1 0[3]]}
check_doclist fts2q-1.2.4 0 0 this {[1 0[0]]}

# TODO(shess): optimize() tests here.



























































































































































































































finish_test

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#*************************************************************************
# This file implements regression tests for SQLite library.  The focus
# of this script is testing the FTS2 module's optimize() function.
#
# $Id: fts2q.test,v 1.2 2008/07/22 23:49:44 shess Exp $
#

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

# If SQLITE_ENABLE_FTS2 is not defined, omit this file.
ifcapable !fts2 {
................................................................................

check_terms   fts2q-1.2   0 0 {a is test this}
check_doclist fts2q-1.2.1 0 0 a {[1 0[2]]}
check_doclist fts2q-1.2.2 0 0 is {[1 0[1]]}
check_doclist fts2q-1.2.3 0 0 test {[1 0[3]]}
check_doclist fts2q-1.2.4 0 0 this {[1 0[0]]}

#*************************************************************************
# Test results when everything is optimized manually.
# NOTE(shess): This is a copy of fts2c-1.3.  I've pulled a copy here
# because fts2q-2 and fts2q-3 should have identical results.
db eval {
  DROP TABLE IF EXISTS t1;
  CREATE VIRTUAL TABLE t1 USING fts2(c);
  INSERT INTO t1 (rowid, c) VALUES (1, 'This is a test');
  INSERT INTO t1 (rowid, c) VALUES (2, 'That was a test');
  INSERT INTO t1 (rowid, c) VALUES (3, 'This is a test');
  DELETE FROM t1 WHERE rowid IN (1,3);
  DROP TABLE IF EXISTS t1old;
  ALTER TABLE t1 RENAME TO t1old;
  CREATE VIRTUAL TABLE t1 USING fts2(c);
  INSERT INTO t1 (rowid, c) SELECT rowid, c FROM t1old;
  DROP TABLE t1old;
}

# Should be a single optimal segment with the same logical results.
do_test fts2q-2.segments {
  execsql {
    SELECT level, idx FROM t1_segdir ORDER BY level, idx;
  }
} {0 0}
do_test fts2q-2.matches {
  execsql {
    SELECT OFFSETS(t1) FROM t1
     WHERE t1 MATCH 'this OR that OR was OR a OR is OR test' ORDER BY rowid;
  }
} {{0 1 0 4 0 2 5 3 0 3 9 1 0 5 11 4}}

check_terms_all fts2q-2.1 {a test that was}
check_doclist_all fts2q-2.1.1 a {[2 0[2]]}
check_doclist_all fts2q-2.1.2 test {[2 0[3]]}
check_doclist_all fts2q-2.1.3 that {[2 0[0]]}
check_doclist_all fts2q-2.1.4 was {[2 0[1]]}

check_terms fts2q-2.2 0 0 {a test that was}
check_doclist fts2q-2.2.1 0 0 a {[2 0[2]]}
check_doclist fts2q-2.2.2 0 0 test {[2 0[3]]}
check_doclist fts2q-2.2.3 0 0 that {[2 0[0]]}
check_doclist fts2q-2.2.4 0 0 was {[2 0[1]]}

#*************************************************************************
# Test results when everything is optimized via optimize().
db eval {
  DROP TABLE IF EXISTS t1;
  CREATE VIRTUAL TABLE t1 USING fts2(c);
  INSERT INTO t1 (rowid, c) VALUES (1, 'This is a test');
  INSERT INTO t1 (rowid, c) VALUES (2, 'That was a test');
  INSERT INTO t1 (rowid, c) VALUES (3, 'This is a test');
  DELETE FROM t1 WHERE rowid IN (1,3);
  SELECT OPTIMIZE(t1) FROM t1 LIMIT 1;
}

# Should be a single optimal segment with the same logical results.
do_test fts2q-3.segments {
  execsql {
    SELECT level, idx FROM t1_segdir ORDER BY level, idx;
  }
} {0 0}
do_test fts2q-3.matches {
  execsql {
    SELECT OFFSETS(t1) FROM t1
     WHERE t1 MATCH 'this OR that OR was OR a OR is OR test' ORDER BY rowid;
  }
} {{0 1 0 4 0 2 5 3 0 3 9 1 0 5 11 4}}

check_terms_all fts2q-3.1 {a test that was}
check_doclist_all fts2q-3.1.1 a {[2 0[2]]}
check_doclist_all fts2q-3.1.2 test {[2 0[3]]}
check_doclist_all fts2q-3.1.3 that {[2 0[0]]}
check_doclist_all fts2q-3.1.4 was {[2 0[1]]}

check_terms fts2q-3.2 0 0 {a test that was}
check_doclist fts2q-3.2.1 0 0 a {[2 0[2]]}
check_doclist fts2q-3.2.2 0 0 test {[2 0[3]]}
check_doclist fts2q-3.2.3 0 0 that {[2 0[0]]}
check_doclist fts2q-3.2.4 0 0 was {[2 0[1]]}

#*************************************************************************
# Test optimize() against a table involving segment merges.
# NOTE(shess): Since there's no transaction, each of the INSERT/UPDATE
# statements generates a segment.
db eval {
  DROP TABLE IF EXISTS t1;
  CREATE VIRTUAL TABLE t1 USING fts2(c);

  INSERT INTO t1 (rowid, c) VALUES (1, 'This is a test');
  INSERT INTO t1 (rowid, c) VALUES (2, 'That was a test');
  INSERT INTO t1 (rowid, c) VALUES (3, 'This is a test');

  UPDATE t1 SET c = 'This is a test one' WHERE rowid = 1;
  UPDATE t1 SET c = 'That was a test one' WHERE rowid = 2;
  UPDATE t1 SET c = 'This is a test one' WHERE rowid = 3;

  UPDATE t1 SET c = 'This is a test two' WHERE rowid = 1;
  UPDATE t1 SET c = 'That was a test two' WHERE rowid = 2;
  UPDATE t1 SET c = 'This is a test two' WHERE rowid = 3;

  UPDATE t1 SET c = 'This is a test three' WHERE rowid = 1;
  UPDATE t1 SET c = 'That was a test three' WHERE rowid = 2;
  UPDATE t1 SET c = 'This is a test three' WHERE rowid = 3;

  UPDATE t1 SET c = 'This is a test four' WHERE rowid = 1;
  UPDATE t1 SET c = 'That was a test four' WHERE rowid = 2;
  UPDATE t1 SET c = 'This is a test four' WHERE rowid = 3;

  UPDATE t1 SET c = 'This is a test' WHERE rowid = 1;
  UPDATE t1 SET c = 'That was a test' WHERE rowid = 2;
  UPDATE t1 SET c = 'This is a test' WHERE rowid = 3;
}

# 2 segments in level 0, 1 in level 1 (18 segments created, 16
# merged).
do_test fts2q-4.segments {
  execsql {
    SELECT level, idx FROM t1_segdir ORDER BY level, idx;
  }
} {0 0 0 1 1 0}

do_test fts2q-4.matches {
  execsql {
    SELECT OFFSETS(t1) FROM t1
     WHERE t1 MATCH 'this OR that OR was OR a OR is OR test' ORDER BY rowid;
  }
} [list {0 0 0 4 0 4 5 2 0 3 8 1 0 5 10 4} \
        {0 1 0 4 0 2 5 3 0 3 9 1 0 5 11 4} \
        {0 0 0 4 0 4 5 2 0 3 8 1 0 5 10 4}]

check_terms_all fts2q-4.1      {a four is one test that this three two was}
check_doclist_all fts2q-4.1.1  a {[1 0[2]] [2 0[2]] [3 0[2]]}
check_doclist_all fts2q-4.1.2  four {}
check_doclist_all fts2q-4.1.3  is {[1 0[1]] [3 0[1]]}
check_doclist_all fts2q-4.1.4  one {}
check_doclist_all fts2q-4.1.5  test {[1 0[3]] [2 0[3]] [3 0[3]]}
check_doclist_all fts2q-4.1.6  that {[2 0[0]]}
check_doclist_all fts2q-4.1.7  this {[1 0[0]] [3 0[0]]}
check_doclist_all fts2q-4.1.8  three {}
check_doclist_all fts2q-4.1.9  two {}
check_doclist_all fts2q-4.1.10 was {[2 0[1]]}

check_terms fts2q-4.2     0 0 {a four test that was}
check_doclist fts2q-4.2.1 0 0 a {[2 0[2]]}
check_doclist fts2q-4.2.2 0 0 four {[2]}
check_doclist fts2q-4.2.3 0 0 test {[2 0[3]]}
check_doclist fts2q-4.2.4 0 0 that {[2 0[0]]}
check_doclist fts2q-4.2.5 0 0 was {[2 0[1]]}

check_terms fts2q-4.3     0 1 {a four is test this}
check_doclist fts2q-4.3.1 0 1 a {[3 0[2]]}
check_doclist fts2q-4.3.2 0 1 four {[3]}
check_doclist fts2q-4.3.3 0 1 is {[3 0[1]]}
check_doclist fts2q-4.3.4 0 1 test {[3 0[3]]}
check_doclist fts2q-4.3.5 0 1 this {[3 0[0]]}

check_terms fts2q-4.4      1 0 {a four is one test that this three two was}
check_doclist fts2q-4.4.1  1 0 a {[1 0[2]] [2 0[2]] [3 0[2]]}
check_doclist fts2q-4.4.2  1 0 four {[1] [2 0[4]] [3 0[4]]}
check_doclist fts2q-4.4.3  1 0 is {[1 0[1]] [3 0[1]]}
check_doclist fts2q-4.4.4  1 0 one {[1] [2] [3]}
check_doclist fts2q-4.4.5  1 0 test {[1 0[3]] [2 0[3]] [3 0[3]]}
check_doclist fts2q-4.4.6  1 0 that {[2 0[0]]}
check_doclist fts2q-4.4.7  1 0 this {[1 0[0]] [3 0[0]]}
check_doclist fts2q-4.4.8  1 0 three {[1] [2] [3]}
check_doclist fts2q-4.4.9  1 0 two {[1] [2] [3]}
check_doclist fts2q-4.4.10 1 0 was {[2 0[1]]}

# Optimize should leave the result in the level of the highest-level
# prior segment.
do_test fts2q-4.5 {
  execsql {
    SELECT OPTIMIZE(t1) FROM t1 LIMIT 1;
    SELECT level, idx FROM t1_segdir ORDER BY level, idx;
  }
} {{Index optimized} 1 0}

# Identical to fts2q-4.matches.
do_test fts2q-4.5.matches {
  execsql {
    SELECT OFFSETS(t1) FROM t1
     WHERE t1 MATCH 'this OR that OR was OR a OR is OR test' ORDER BY rowid;
  }
} [list {0 0 0 4 0 4 5 2 0 3 8 1 0 5 10 4} \
        {0 1 0 4 0 2 5 3 0 3 9 1 0 5 11 4} \
        {0 0 0 4 0 4 5 2 0 3 8 1 0 5 10 4}]

check_terms_all fts2q-4.5.1     {a is test that this was}
check_doclist_all fts2q-4.5.1.1 a {[1 0[2]] [2 0[2]] [3 0[2]]}
check_doclist_all fts2q-4.5.1.2 is {[1 0[1]] [3 0[1]]}
check_doclist_all fts2q-4.5.1.3 test {[1 0[3]] [2 0[3]] [3 0[3]]}
check_doclist_all fts2q-4.5.1.4 that {[2 0[0]]}
check_doclist_all fts2q-4.5.1.5 this {[1 0[0]] [3 0[0]]}
check_doclist_all fts2q-4.5.1.6 was {[2 0[1]]}

check_terms fts2q-4.5.2     1 0 {a is test that this was}
check_doclist fts2q-4.5.2.1 1 0 a {[1 0[2]] [2 0[2]] [3 0[2]]}
check_doclist fts2q-4.5.2.2 1 0 is {[1 0[1]] [3 0[1]]}
check_doclist fts2q-4.5.2.3 1 0 test {[1 0[3]] [2 0[3]] [3 0[3]]}
check_doclist fts2q-4.5.2.4 1 0 that {[2 0[0]]}
check_doclist fts2q-4.5.2.5 1 0 this {[1 0[0]] [3 0[0]]}
check_doclist fts2q-4.5.2.6 1 0 was {[2 0[1]]}

# Re-optimizing does nothing.
do_test fts2q-5.0 {
  execsql {
    SELECT OPTIMIZE(t1) FROM t1 LIMIT 1;
    SELECT level, idx FROM t1_segdir ORDER BY level, idx;
  }
} {{Index already optimal} 1 0}

# Even if we move things around, still does nothing.
do_test fts2q-5.1 {
  execsql {
    UPDATE t1_segdir SET level = 2 WHERE level = 1 AND idx = 0;
    SELECT OPTIMIZE(t1) FROM t1 LIMIT 1;
    SELECT level, idx FROM t1_segdir ORDER BY level, idx;
  }
} {{Index already optimal} 2 0}

finish_test