SQLite

  int nTabName;             /* Number of UTF-8 characters in zTabName */
  const char *zTabName;     /* Original name of the table */
  Vdbe *v;
#ifndef SQLITE_OMIT_TRIGGER
  char *zWhere = 0;         /* Where clause to locate temp triggers */
#endif
  VTable *pVTab = 0;        /* Non-zero if this is a v-tab with an xRename() */
  u32 savedDbFlags;         /* Saved value of db->mDbFlags */

  savedDbFlags = db->mDbFlags;  
  if( NEVER(db->mallocFailed) ) goto exit_rename_table;
  assert( pSrc->nSrc==1 );
  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );

  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
  if( !pTab ) goto exit_rename_table;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  zDb = db->aDb[iDb].zDbSName;
  db->mDbFlags |= DBFLAG_PreferBuiltin;

  /* Get a NULL terminated version of the new table name. */
  zName = sqlite3NameFromToken(db, pName);
  if( !zName ) goto exit_rename_table;

  /* Check that a table or index named 'zName' does not already exist
  ** in database iDb. If so, this is an error.

  /* Drop and reload the internal table schema. */
  reloadTableSchema(pParse, pTab, zName);

exit_rename_table:
  sqlite3SrcListDelete(db, pSrc);
  sqlite3DbFree(db, zName);
  db->mDbFlags = savedDbFlags;
}

/*
** This function is called after an "ALTER TABLE ... ADD" statement
** has been parsed. Argument pColDef contains the text of the new
** column definition.
**

    sqlite3ValueFree(pVal);
  }

  /* Modify the CREATE TABLE statement. */
  zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
  if( zCol ){
    char *zEnd = &zCol[pColDef->n-1];
    u32 savedDbFlags = db->mDbFlags;
    while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
      *zEnd-- = '\0';
    }
    db->mDbFlags |= DBFLAG_PreferBuiltin;
    sqlite3NestedParse(pParse, 
        "UPDATE \"%w\".%s SET "
          "sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
        "WHERE type = 'table' AND name = %Q", 
      zDb, MASTER_NAME, pNew->addColOffset, zCol, pNew->addColOffset+1,
      zTab
    );
    sqlite3DbFree(db, zCol);
    db->mDbFlags = savedDbFlags;
  }

  /* Make sure the schema version is at least 3.  But do not upgrade
  ** from less than 3 to 4, as that will corrupt any preexisting DESC
  ** index.
  */
  r1 = sqlite3GetTempReg(pParse);

      while( ALWAYS(p) && p->pNext!=pIndex ){ p = p->pNext; }
      if( ALWAYS(p && p->pNext==pIndex) ){
        p->pNext = pIndex->pNext;
      }
    }
    freeIndex(db, pIndex);
  }
  db->mDbFlags |= DBFLAG_SchemaChange;
}

/*
** Look through the list of open database files in db->aDb[] and if
** any have been closed, remove them from the list.  Reallocate the
** db->aDb[] structure to a smaller size, if possible.
**

  sqlite3BtreeEnterAll(db);
  for(i=0; i<db->nDb; i++){
    Db *pDb = &db->aDb[i];
    if( pDb->pSchema ){
      sqlite3SchemaClear(pDb->pSchema);
    }
  }
  db->mDbFlags &= ~DBFLAG_SchemaChange;
  sqlite3VtabUnlockList(db);
  sqlite3BtreeLeaveAll(db);
  sqlite3CollapseDatabaseArray(db);
}

/*
** This routine is called when a commit occurs.
*/
void sqlite3CommitInternalChanges(sqlite3 *db){
  db->mDbFlags &= ~DBFLAG_SchemaChange;
}

/*
** Delete memory allocated for the column names of a table or view (the
** Table.aCol[] array).
*/
void sqlite3DeleteColumnNames(sqlite3 *db, Table *pTable){

  assert( iDb>=0 && iDb<db->nDb );
  assert( zTabName );
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
  testcase( zTabName[0]==0 );  /* Zero-length table names are allowed */
  pDb = &db->aDb[iDb];
  p = sqlite3HashInsert(&pDb->pSchema->tblHash, zTabName, 0);
  sqlite3DeleteTable(db, p);
  db->mDbFlags |= DBFLAG_SchemaChange;
}

/*
** Given a token, return a string that consists of the text of that
** token.  Space to hold the returned string
** is obtained from sqliteMalloc() and must be freed by the calling
** function.

    *pUnqual = pName2;
    iDb = sqlite3FindDb(db, pName1);
    if( iDb<0 ){
      sqlite3ErrorMsg(pParse, "unknown database %T", pName1);
      return -1;
    }
  }else{
    assert( db->init.iDb==0 || db->init.busy
             || (db->mDbFlags & DBFLAG_Vacuum)!=0);
    iDb = db->init.iDb;
    *pUnqual = pName1;
  }
  return iDb;
}

/*

    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, p);
    if( pOld ){
      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
      sqlite3OomFault(db);
      return;
    }
    pParse->pNewTable = 0;
    db->mDbFlags |= DBFLAG_SchemaChange;

#ifndef SQLITE_OMIT_ALTERTABLE
    if( !p->pSelect ){
      const char *zName = (const char *)pParse->sNameToken.z;
      int nName;
      assert( !pSelect && pCons && pEnd );
      if( pCons->z==0 ){

    p = sqlite3HashInsert(&pIndex->pSchema->idxHash, 
                          pIndex->zName, pIndex);
    if( p ){
      assert( p==pIndex );  /* Malloc must have failed */
      sqlite3OomFault(db);
      goto exit_create_index;
    }
    db->mDbFlags |= DBFLAG_SchemaChange;
    if( pTblName!=0 ){
      pIndex->tnum = db->init.newTnum;
    }
  }

  /* If this is the initial CREATE INDEX statement (or CREATE TABLE if the
  ** index is an implied index for a UNIQUE or PRIMARY KEY constraint) then

      bestScore = score;
    }
    p = p->pNext;
  }

  /* If no match is found, search the built-in functions.
  **
  ** If the DBFLAG_PreferBuiltin flag is set, then search the built-in
  ** functions even if a prior app-defined function was found.  And give
  ** priority to built-in functions.
  **
  ** Except, if createFlag is true, that means that we are trying to
  ** install a new function.  Whatever FuncDef structure is returned it will
  ** have fields overwritten with new information appropriate for the
  ** new function.  But the FuncDefs for built-in functions are read-only.
  ** So we must not search for built-ins when creating a new function.
  */ 
  if( !createFlag && (pBest==0 || (db->mDbFlags & DBFLAG_PreferBuiltin)!=0) ){
    bestScore = 0;
    h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % SQLITE_FUNC_HASH_SZ;
    p = functionSearch(h, zName);
    while( p ){
      int score = matchQuality(p, nArg, enc);
      if( score>bestScore ){
        pBest = p;

static int autoIncBegin(
  Parse *pParse,      /* Parsing context */
  int iDb,            /* Index of the database holding pTab */
  Table *pTab         /* The table we are writing to */
){
  int memId = 0;      /* Register holding maximum rowid */
  if( (pTab->tabFlags & TF_Autoincrement)!=0
   && (pParse->db->mDbFlags & DBFLAG_Vacuum)==0
  ){
    Parse *pToplevel = sqlite3ParseToplevel(pParse);
    AutoincInfo *pInfo;

    pInfo = pToplevel->pAinc;
    while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
    if( pInfo==0 ){

  if( pDest->iPKey!=pSrc->iPKey ){
    return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
  }
  for(i=0; i<pDest->nCol; i++){
    Column *pDestCol = &pDest->aCol[i];
    Column *pSrcCol = &pSrc->aCol[i];
#ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
    if( (db->mDbFlags & DBFLAG_Vacuum)==0 
     && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN 
    ){
      return 0;    /* Neither table may have __hidden__ columns */
    }
#endif
    if( pDestCol->affinity!=pSrcCol->affinity ){
      return 0;    /* Affinity must be the same on all columns */

  iSrc = pParse->nTab++;
  iDest = pParse->nTab++;
  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
  regData = sqlite3GetTempReg(pParse);
  regRowid = sqlite3GetTempReg(pParse);
  sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
  assert( HasRowid(pDest) || destHasUniqueIdx );
  if( (db->mDbFlags & DBFLAG_Vacuum)==0 && (
      (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
   || destHasUniqueIdx                              /* (2) */
   || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
  )){
    /* In some circumstances, we are able to run the xfer optimization
    ** only if the destination table is initially empty. Unless the
    ** DBFLAG_Vacuum flag is set, this block generates code to make
    ** that determination. If DBFLAG_Vacuum is set, then the destination
    ** table is always empty.
    **
    ** Conditions under which the destination must be empty:
    **
    ** (1) There is no INTEGER PRIMARY KEY but there are indices.
    **     (If the destination is not initially empty, the rowid fields
    **     of index entries might need to change.)

    }else if( pDest->pIndex==0 ){
      addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
    }else{
      addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
      assert( (pDest->tabFlags & TF_Autoincrement)==0 );
    }
    sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
    if( db->mDbFlags & DBFLAG_Vacuum ){
      sqlite3VdbeAddOp3(v, OP_Last, iDest, 0, -1);
      insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|
                           OPFLAG_APPEND|OPFLAG_USESEEKRESULT;
    }else{
      insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND;
    }
    sqlite3VdbeAddOp4(v, OP_Insert, iDest, regData, regRowid,

    VdbeComment((v, "%s", pSrcIdx->zName));
    sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
    sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
    sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
    VdbeComment((v, "%s", pDestIdx->zName));
    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
    sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
    if( db->mDbFlags & DBFLAG_Vacuum ){
      /* This INSERT command is part of a VACUUM operation, which guarantees
      ** that the destination table is empty. If all indexed columns use
      ** collation sequence BINARY, then it can also be assumed that the
      ** index will be populated by inserting keys in strictly sorted 
      ** order. In this case, instead of seeking within the b-tree as part
      ** of every OP_IdxInsert opcode, an OP_Last is added before the
      ** OP_IdxInsert to seek to the point within the b-tree where each key 

  /* Obtain all b-tree mutexes before making any calls to BtreeRollback(). 
  ** This is important in case the transaction being rolled back has
  ** modified the database schema. If the b-tree mutexes are not taken
  ** here, then another shared-cache connection might sneak in between
  ** the database rollback and schema reset, which can cause false
  ** corruption reports in some cases.  */
  sqlite3BtreeEnterAll(db);
  schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;

  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;
    if( p ){
      if( sqlite3BtreeIsInTrans(p) ){
        inTrans = 1;
      }
      sqlite3BtreeRollback(p, tripCode, !schemaChange);
    }
  }
  sqlite3VtabRollback(db);
  sqlite3EndBenignMalloc();

  if( (db->mDbFlags&DBFLAG_SchemaChange)!=0 && db->init.busy==0 ){
    sqlite3ExpirePreparedStatements(db);
    sqlite3ResetAllSchemasOfConnection(db);
  }
  sqlite3BtreeLeaveAll(db);

  /* Any deferred constraint violations have now been resolved. */
  db->nDeferredCons = 0;

    db->init.iDb = iDb;
    db->init.newTnum = sqlite3Atoi(argv[1]);
    db->init.orphanTrigger = 0;
    TESTONLY(rcp = ) sqlite3_prepare(db, argv[2], -1, &pStmt, 0);
    rc = db->errCode;
    assert( (rc&0xFF)==(rcp&0xFF) );
    db->init.iDb = saved_iDb;
    assert( saved_iDb==0 || (db->mDbFlags & DBFLAG_Vacuum)!=0 );
    if( SQLITE_OK!=rc ){
      if( db->init.orphanTrigger ){
        assert( iDb==1 );
      }else{
        pData->rc = rc;
        if( rc==SQLITE_NOMEM ){
          sqlite3OomFault(db);

**
** After a database is initialized, the DB_SchemaLoaded bit is set
** bit is set in the flags field of the Db structure. If the database
** file was of zero-length, then the DB_Empty flag is also set.
*/
int sqlite3Init(sqlite3 *db, char **pzErrMsg){
  int i, rc;
  int commit_internal = !(db->mDbFlags&DBFLAG_SchemaChange);
  
  assert( sqlite3_mutex_held(db->mutex) );
  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
  assert( db->init.busy==0 );
  rc = SQLITE_OK;
  db->init.busy = 1;
  ENC(db) = SCHEMA_ENC(db);

struct sqlite3 {
  sqlite3_vfs *pVfs;            /* OS Interface */
  struct Vdbe *pVdbe;           /* List of active virtual machines */
  CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
  sqlite3_mutex *mutex;         /* Connection mutex */
  Db *aDb;                      /* All backends */
  int nDb;                      /* Number of backends currently in use */
  u32 mDbFlags;                 /* flags recording internal state */
  u32 flags;                    /* flags settable by pragmas. See below */
  i64 lastRowid;                /* ROWID of most recent insert (see above) */
  i64 szMmap;                   /* Default mmap_size setting */
  unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
  int errCode;                  /* Most recent error code (SQLITE_*) */
  int errMask;                  /* & result codes with this before returning */
  int iSysErrno;                /* Errno value from last system error */
  u16 dbOptFlags;               /* Flags to enable/disable optimizations */

#define SQLITE_ReadUncommit   0x00000400  /* READ UNCOMMITTED in shared-cache */
#define SQLITE_NoCkptOnClose  0x00000800  /* No checkpoint on close()/DETACH */
#define SQLITE_ReverseOrder   0x00001000  /* Reverse unordered SELECTs */
#define SQLITE_RecTriggers    0x00002000  /* Enable recursive triggers */
#define SQLITE_ForeignKeys    0x00004000  /* Enforce foreign key constraints  */
#define SQLITE_AutoIndex      0x00008000  /* Enable automatic indexes */
#define SQLITE_LoadExtension  0x00010000  /* Enable load_extension */
#define SQLITE_LoadExtFunc    0x00020000  /* Enable load_extension() SQL func */
#define SQLITE_EnableTrigger  0x00040000  /* True to enable triggers */
#define SQLITE_DeferFKs       0x00080000  /* Defer all FK constraints */
#define SQLITE_QueryOnly      0x00100000  /* Disable database changes */
#define SQLITE_CellSizeCk     0x00200000  /* Check btree cell sizes on load */
#define SQLITE_Fts3Tokenizer  0x00400000  /* Enable fts3_tokenizer(2) */
#define SQLITE_EnableQPSG     0x00800000  /* Query Planner Stability Guarantee */






/* Flags used only if debugging */
#ifdef SQLITE_DEBUG
#define SQLITE_SqlTrace       0x08000000  /* Debug print SQL as it executes */
#define SQLITE_VdbeListing    0x10000000  /* Debug listings of VDBE programs */
#define SQLITE_VdbeTrace      0x20000000  /* True to trace VDBE execution */
#define SQLITE_VdbeAddopTrace 0x40000000  /* Trace sqlite3VdbeAddOp() calls */
#define SQLITE_VdbeEQP        0x80000000  /* Debug EXPLAIN QUERY PLAN */
#endif

/*
** Allowed values for sqlite3.mDbFlags
*/
#define DBFLAG_SchemaChange   0x0001  /* Uncommitted Hash table changes */
#define DBFLAG_PreferBuiltin  0x0002  /* Preference to built-in funcs */
#define DBFLAG_Vacuum         0x0004  /* Currently in a VACUUM */

/*
** Bits of the sqlite3.dbOptFlags field that are used by the
** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
** selectively disable various optimizations.
*/
#define SQLITE_QueryFlattener 0x0001   /* Query flattening */

    if( pTrigger->pSchema==pTrigger->pTabSchema ){
      Table *pTab = tableOfTrigger(pTrigger);
      Trigger **pp;
      for(pp=&pTab->pTrigger; *pp!=pTrigger; pp=&((*pp)->pNext));
      *pp = (*pp)->pNext;
    }
    sqlite3DeleteTrigger(db, pTrigger);
    db->mDbFlags |= DBFLAG_SchemaChange;
  }
}

/*
** pEList is the SET clause of an UPDATE statement.  Each entry
** in pEList is of the format <id>=<expr>.  If any of the entries
** in pEList have an <id> which matches an identifier in pIdList,

/*
** This routine implements the OP_Vacuum opcode of the VDBE.
*/
int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db, int iDb){
  int rc = SQLITE_OK;     /* Return code from service routines */
  Btree *pMain;           /* The database being vacuumed */
  Btree *pTemp;           /* The temporary database we vacuum into */
  u16 saved_mDbFlags;     /* Saved value of db->mDbFlags */
  u32 saved_flags;        /* Saved value of db->flags */
  int saved_nChange;      /* Saved value of db->nChange */
  int saved_nTotalChange; /* Saved value of db->nTotalChange */
  u8 saved_mTrace;        /* Saved trace settings */
  Db *pDb = 0;            /* Database to detach at end of vacuum */
  int isMemDb;            /* True if vacuuming a :memory: database */
  int nRes;               /* Bytes of reserved space at the end of each page */
  int nDb;                /* Number of attached databases */

    return SQLITE_ERROR;
  }

  /* Save the current value of the database flags so that it can be 
  ** restored before returning. Then set the writable-schema flag, and
  ** disable CHECK and foreign key constraints.  */
  saved_flags = db->flags;
  saved_mDbFlags = db->mDbFlags;
  saved_nChange = db->nChange;
  saved_nTotalChange = db->nTotalChange;
  saved_mTrace = db->mTrace;
  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
  db->mDbFlags |= DBFLAG_PreferBuiltin | DBFLAG_Vacuum;
  db->flags &= ~(SQLITE_ForeignKeys | SQLITE_ReverseOrder | SQLITE_CountRows);
  db->mTrace = 0;

  zDbMain = db->aDb[iDb].zDbSName;
  pMain = db->aDb[iDb].pBt;
  isMemDb = sqlite3PagerIsMemdb(sqlite3BtreePager(pMain));

  rc = execSqlF(db, pzErrMsg,
      "SELECT'INSERT INTO vacuum_db.'||quote(name)"
      "||' SELECT*FROM\"%w\".'||quote(name)"
      "FROM vacuum_db.sqlite_master "
      "WHERE type='table'AND coalesce(rootpage,1)>0",
      zDbMain
  );
  assert( (db->mDbFlags & DBFLAG_Vacuum)!=0 );
  db->mDbFlags &= ~DBFLAG_Vacuum;
  if( rc!=SQLITE_OK ) goto end_of_vacuum;

  /* Copy the triggers, views, and virtual tables from the main database
  ** over to the temporary database.  None of these objects has any
  ** associated storage, so all we have to do is copy their entries
  ** from the SQLITE_MASTER table.
  */

  assert( rc==SQLITE_OK );
  rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes,1);

end_of_vacuum:
  /* Restore the original value of db->flags */
  db->init.iDb = 0;
  db->mDbFlags = saved_mDbFlags;
  db->flags = saved_flags;
  db->nChange = saved_nChange;
  db->nTotalChange = saved_nTotalChange;
  db->mTrace = saved_mTrace;
  sqlite3BtreeSetPageSize(pMain, -1, -1, 1);

  /* Currently there is an SQL level transaction open on the vacuum

        }
        db->isTransactionSavepoint = 0;
        rc = p->rc;
      }else{
        int isSchemaChange;
        iSavepoint = db->nSavepoint - iSavepoint - 1;
        if( p1==SAVEPOINT_ROLLBACK ){
          isSchemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0;
          for(ii=0; ii<db->nDb; ii++){
            rc = sqlite3BtreeTripAllCursors(db->aDb[ii].pBt,
                                       SQLITE_ABORT_ROLLBACK,
                                       isSchemaChange==0);
            if( rc!=SQLITE_OK ) goto abort_due_to_error;
          }
        }else{
          isSchemaChange = 0;
        }
        for(ii=0; ii<db->nDb; ii++){
          rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
          if( rc!=SQLITE_OK ){
            goto abort_due_to_error;
          }
        }
        if( isSchemaChange ){
          sqlite3ExpirePreparedStatements(db);
          sqlite3ResetAllSchemasOfConnection(db);
          db->mDbFlags |= DBFLAG_SchemaChange;
        }
      }
  
      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
      ** savepoints nested inside of the savepoint being operated on. */
      while( db->pSavepoint!=pSavepoint ){
        pTmp = db->pSavepoint;

  assert( pDb->pBt!=0 );
  assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
  /* See note about index shifting on OP_ReadCookie */
  rc = sqlite3BtreeUpdateMeta(pDb->pBt, pOp->p2, pOp->p3);
  if( pOp->p2==BTREE_SCHEMA_VERSION ){
    /* When the schema cookie changes, record the new cookie internally */
    pDb->pSchema->schema_cookie = pOp->p3;
    db->mDbFlags |= DBFLAG_SchemaChange;
  }else if( pOp->p2==BTREE_FILE_FORMAT ){
    /* Record changes in the file format */
    pDb->pSchema->file_format = pOp->p3;
  }
  if( pOp->p1==1 ){
    /* Invalidate all prepared statements whenever the TEMP database
    ** schema is changed.  Ticket #1644 */