fts5SetVtabError(pTab, 
          "'rebuild' may not be used with a contentless fts5 table"
      );
      rc = SQLITE_ERROR;
    }else{
      rc = sqlite3Fts5StorageRebuild(pTab->pStorage);
    }


  }else if( 0==sqlite3_stricmp("integrity-check", z) ){
    rc = sqlite3Fts5StorageIntegrity(pTab->pStorage);
  }else{
    rc = sqlite3Fts5ConfigSetValue(pTab->pConfig, z, pVal, &bError);
    if( rc==SQLITE_OK ){
      if( bError ){
        rc = SQLITE_ERROR;

      fts5SetVtabError(pTab, 
          "'rebuild' may not be used with a contentless fts5 table"
      );
      rc = SQLITE_ERROR;
    }else{
      rc = sqlite3Fts5StorageRebuild(pTab->pStorage);
    }
  }else if( 0==sqlite3_stricmp("optimize", z) ){
    rc = sqlite3Fts5StorageOptimize(pTab->pStorage);
  }else if( 0==sqlite3_stricmp("integrity-check", z) ){
    rc = sqlite3Fts5StorageIntegrity(pTab->pStorage);
  }else{
    rc = sqlite3Fts5ConfigSetValue(pTab->pConfig, z, pVal, &bError);
    if( rc==SQLITE_OK ){
      if( bError ){
        rc = SQLITE_ERROR;

/*
** Return the total number of entries read from the %_data table by 
** this connection since it was created.
*/
int sqlite3Fts5IndexReads(Fts5Index *p);

int sqlite3Fts5IndexReinit(Fts5Index *p);


/*
** End of interface to code in fts5_index.c.
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_hash.c. 
................................................................................

int sqlite3Fts5StorageConfigValue(Fts5Storage *p, const char*, sqlite3_value*);

int sqlite3Fts5StorageSpecialDelete(Fts5Storage *p, i64 iDel, sqlite3_value**);

int sqlite3Fts5StorageDeleteAll(Fts5Storage *p);
int sqlite3Fts5StorageRebuild(Fts5Storage *p);


/*
** End of interface to code in fts5_storage.c.
**************************************************************************/


/**************************************************************************

/*
** Return the total number of entries read from the %_data table by 
** this connection since it was created.
*/
int sqlite3Fts5IndexReads(Fts5Index *p);

int sqlite3Fts5IndexReinit(Fts5Index *p);
int sqlite3Fts5IndexOptimize(Fts5Index *p);

/*
** End of interface to code in fts5_index.c.
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_hash.c. 
................................................................................

int sqlite3Fts5StorageConfigValue(Fts5Storage *p, const char*, sqlite3_value*);

int sqlite3Fts5StorageSpecialDelete(Fts5Storage *p, i64 iDel, sqlite3_value**);

int sqlite3Fts5StorageDeleteAll(Fts5Storage *p);
int sqlite3Fts5StorageRebuild(Fts5Storage *p);
int sqlite3Fts5StorageOptimize(Fts5Storage *p);

/*
** End of interface to code in fts5_storage.c.
**************************************************************************/


/**************************************************************************

**     large doclists with very small doclists.
**
**   * extra fields in the "structure record" record the state of ongoing
**     incremental merge operations.
**
*/


#define FTS5_WORK_UNIT      64    /* Number of leaf pages in unit of work */
#define FTS5_CRISIS_MERGE   16    /* Maximum number of segments to merge */

#define FTS5_MIN_DLIDX_SIZE  4    /* Add dlidx if this many empty pages */

/*
** Details:
................................................................................
  ){
    fts5IndexMergeLevel(p, iIdx, &pStruct, iLvl, 0);
    fts5StructurePromote(p, iLvl+1, pStruct);
    iLvl++;
  }
  *ppStruct = pStruct;
}







typedef struct Fts5FlushCtx Fts5FlushCtx;
struct Fts5FlushCtx {
  Fts5Index *pIdx;
  Fts5SegWriter writer; 
};

................................................................................

  /* Flush the terms and each prefix index to disk */
  for(i=0; i<=pConfig->nPrefix; i++){
    fts5FlushOneHash(p, i, &nLeaf);
  }
  p->nPendingData = 0;
}





























































/*
** Return a simple checksum value based on the arguments.
*/
static u64 fts5IndexEntryCksum(
  i64 iRowid, 
  int iCol, 
................................................................................
    }
  }

  fts5StructureRelease(pStruct);
  sqlite3_free(aBuf);
}

static int fts5IndexReturn(Fts5Index *p){
  int rc = p->rc;
  p->rc = SQLITE_OK;
  return rc;
}

/*
** Run internal checks to ensure that the FTS index (a) is internally 
** consistent and (b) contains entries for which the XOR of the checksums
** as calculated by fts5IndexEntryCksum() is cksum.
**
** Return SQLITE_CORRUPT if any of the internal checks fail, or if the
** checksum does not match. Return SQLITE_OK if all checks pass without

**     large doclists with very small doclists.
**
**   * extra fields in the "structure record" record the state of ongoing
**     incremental merge operations.
**
*/

#define FTS5_OPT_WORK_UNIT  1000  /* Number of leaf pages per optimize step */
#define FTS5_WORK_UNIT      64    /* Number of leaf pages in unit of work */
#define FTS5_CRISIS_MERGE   16    /* Maximum number of segments to merge */

#define FTS5_MIN_DLIDX_SIZE  4    /* Add dlidx if this many empty pages */

/*
** Details:
................................................................................
  ){
    fts5IndexMergeLevel(p, iIdx, &pStruct, iLvl, 0);
    fts5StructurePromote(p, iLvl+1, pStruct);
    iLvl++;
  }
  *ppStruct = pStruct;
}

static int fts5IndexReturn(Fts5Index *p){
  int rc = p->rc;
  p->rc = SQLITE_OK;
  return rc;
}

typedef struct Fts5FlushCtx Fts5FlushCtx;
struct Fts5FlushCtx {
  Fts5Index *pIdx;
  Fts5SegWriter writer; 
};

................................................................................

  /* Flush the terms and each prefix index to disk */
  for(i=0; i<=pConfig->nPrefix; i++){
    fts5FlushOneHash(p, i, &nLeaf);
  }
  p->nPendingData = 0;
}


int sqlite3Fts5IndexOptimize(Fts5Index *p){
  Fts5Config *pConfig = p->pConfig;
  int i;

  fts5IndexFlush(p);
  for(i=0; i<=pConfig->nPrefix; i++){
    Fts5Structure *pStruct = fts5StructureRead(p, i);
    Fts5Structure *pNew = 0;
    int nSeg = 0;
    if( pStruct ){
      nSeg = fts5StructureCountSegments(pStruct);
      if( nSeg>1 ){
        int nByte = sizeof(Fts5Structure);
        nByte += (pStruct->nLevel+1) * sizeof(Fts5StructureLevel);
        pNew = (Fts5Structure*)sqlite3Fts5MallocZero(&p->rc, nByte);
      }
    }
    if( pNew ){
      Fts5StructureLevel *pLvl;
      int nByte = nSeg * sizeof(Fts5StructureSegment);
      pNew->nLevel = pStruct->nLevel+1;
      pNew->nWriteCounter = pStruct->nWriteCounter;
      pLvl = &pNew->aLevel[pStruct->nLevel];
      pLvl->aSeg = (Fts5StructureSegment*)sqlite3Fts5MallocZero(&p->rc, nByte);
      if( pLvl->aSeg ){
        int iLvl, iSeg;
        int iSegOut = 0;
        for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
          for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
            pLvl->aSeg[iSegOut] = pStruct->aLevel[iLvl].aSeg[iSeg];
            iSegOut++;
          }
        }
        pLvl->nSeg = nSeg;
      }else{
        sqlite3_free(pNew);
        pNew = 0;
      }
    }

    if( pNew ){
      int iLvl = pNew->nLevel-1;
      while( p->rc==SQLITE_OK && pNew->aLevel[iLvl].nSeg>0 ){
        int nRem = FTS5_OPT_WORK_UNIT;
        fts5IndexMergeLevel(p, i, &pNew, iLvl, &nRem);
      }

      fts5StructureWrite(p, i, pNew);
      fts5StructureRelease(pNew);
    }

    fts5StructureRelease(pStruct);
  }

  return fts5IndexReturn(p); 
}



/*
** Return a simple checksum value based on the arguments.
*/
static u64 fts5IndexEntryCksum(
  i64 iRowid, 
  int iCol, 
................................................................................
    }
  }

  fts5StructureRelease(pStruct);
  sqlite3_free(aBuf);
}







/*
** Run internal checks to ensure that the FTS index (a) is internally 
** consistent and (b) contains entries for which the XOR of the checksums
** as calculated by fts5IndexEntryCksum() is cksum.
**
** Return SQLITE_CORRUPT if any of the internal checks fail, or if the
** checksum does not match. Return SQLITE_OK if all checks pass without

  /* Write the averages record */
  if( rc==SQLITE_OK ){
    rc = fts5StorageSaveTotals(p);
  }
  return rc;
}





/*
** Allocate a new rowid. This is used for "external content" tables when
** a NULL value is inserted into the rowid column. The new rowid is allocated
** by inserting a dummy row into the %_docsize table. The dummy will be
** overwritten later.
*/

  /* Write the averages record */
  if( rc==SQLITE_OK ){
    rc = fts5StorageSaveTotals(p);
  }
  return rc;
}

int sqlite3Fts5StorageOptimize(Fts5Storage *p){
  return sqlite3Fts5IndexOptimize(p->pIndex);
}

/*
** Allocate a new rowid. This is used for "external content" tables when
** a NULL value is inserted into the rowid column. The new rowid is allocated
** by inserting a dummy row into the %_docsize table. The dummy will be
** overwritten later.
*/

# 2014 Dec 20
#
# 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.
#
#***********************************************************************
#
#

source [file join [file dirname [info script]] fts5_common.tcl]
set testprefix fts5optimize

proc rnddoc {nWord} {
  set vocab {a b c d e f g h i j k l m n o p q r s t u v w x y z}
  set nVocab [llength $vocab]
  set ret [list]
  for {set i 0} {$i < $nWord} {incr i} {
    lappend ret [lindex $vocab [expr {int(rand() * $nVocab)}]]
  }
  return $ret
}


foreach {tn nStep} {
  1 2
  2 10
  3 50
  4 500
} {
if {$tn!=4} continue
  reset_db
  db func rnddoc rnddoc
  do_execsql_test 1.$tn.1 {
    CREATE VIRTUAL TABLE t1 USING fts5(x, y);
  }
  do_test 1.$tn.2 {
    for {set i 0} {$i < $nStep} {incr i} {
      execsql { INSERT INTO t1 VALUES( rnddoc(5), rnddoc(5) ) }
    }
  } {}

  do_execsql_test 1.$tn.3 {
    INSERT INTO t1(t1) VALUES('integrity-check');
  }

  do_execsql_test 1.$tn.4 {
    INSERT INTO t1(t1) VALUES('optimize');
  }

  do_execsql_test 1.$tn.5 {
    INSERT INTO t1(t1) VALUES('integrity-check');
  }
}

finish_test