/*
** Table p is a virtual table. This function moves all elements in the
** p->pVTable list to the sqlite3.pDisconnect lists of their associated
** database connections to be disconnected at the next opportunity.
** Except, if argument db is not NULL, then the entry associated with
** connection db is left in the p->pVTable list.
*/
static VTable *vtabDisconnectAll(sqlite3 *db, Table *p){
VTable *pRet = 0;
VTable *pVTable = p->pVTable;
p->pVTable = 0;
/* Assert that the mutex (if any) associated with the BtShared database
** that contains table p is held by the caller. See header comments
** above function sqlite3VtabUnlockList() for an explanation of why
** this makes it safe to access the sqlite3.pDisconnect list of any
** database connection that may have an entry in the p->pVTable list. */
assert( db==0 ||
sqlite3BtreeHoldsMutex(db->aDb[sqlite3SchemaToIndex(db, p->pSchema)].pBt)
);
while( pVTable ){
sqlite3 *db2 = pVTable->db;
VTable *pNext = pVTable->pNext;
assert( db2 );
if( db2==db ){
pRet = pVTable;
p->pVTable = pRet;
pRet->pNext = 0;
}else{
pVTable->pNext = db2->pDisconnect;
db2->pDisconnect = pVTable;
}
pVTable = pNext;
}
assert( !db || pRet );
return pRet;
}
/*
** Load the content of the sqlite_stat1 table into the index hash tables.
*/
int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
analysisInfo sInfo;
HashElem *i;
char *zSql;
int rc;
assert( iDb>=0 && iDb<db->nDb );
assert( db->aDb[iDb].pBt!=0 );
assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
/* Clear any prior statistics */
for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
Index *pIdx = sqliteHashData(i);
sqlite3DefaultRowEst(pIdx);
}
/* Check to make sure the sqlite_stat1 table existss */
sInfo.db = db;
sInfo.zDatabase = db->aDb[iDb].zName;
if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){
return SQLITE_ERROR;
}
/* Load new statistics out of the sqlite_stat1 table */
zSql = sqlite3MPrintf(db, "SELECT idx, stat FROM %Q.sqlite_stat1",
sInfo.zDatabase);
sqlite3SafetyOff(db);
rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
sqlite3SafetyOn(db);
sqlite3_free(zSql);
return rc;
}
/*
** Register this backup object with the associated source pager for
** callbacks when pages are changed or the cache invalidated.
*/
static void attachBackupObject(sqlite3_backup *p){
sqlite3_backup **pp;
assert( sqlite3BtreeHoldsMutex(p->pSrc) );
pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
p->pNext = *pp;
*pp = p;
p->isAttached = 1;
}
/*
** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
*/
static int sqlite3Prepare(
sqlite3 *db, /* Database handle. */
const char *zSql, /* UTF-8 encoded SQL statement. */
int nBytes, /* Length of zSql in bytes. */
int saveSqlFlag, /* True to copy SQL text into the sqlite3_stmt */
sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */
const char **pzTail /* OUT: End of parsed string */
){
Parse sParse;
char *zErrMsg = 0;
int rc = SQLITE_OK;
int i;
assert( ppStmt );
*ppStmt = 0;
if( sqlite3SafetyOn(db) ){
return SQLITE_MISUSE;
}
assert( !db->mallocFailed );
assert( sqlite3_mutex_held(db->mutex) );
/* Check to verify that it is possible to get a read lock on all
** database schemas. The inability to get a read lock indicates that
** some other database connection is holding a write-lock, which in
** turn means that the other connection has made uncommitted changes
** to the schema.
**
** Were we to proceed and prepare the statement against the uncommitted
** schema changes and if those schema changes are subsequently rolled
** back and different changes are made in their place, then when this
** prepared statement goes to run the schema cookie would fail to detect
** the schema change. Disaster would follow.
**
** This thread is currently holding mutexes on all Btrees (because
** of the sqlite3BtreeEnterAll() in sqlite3LockAndPrepare()) so it
** is not possible for another thread to start a new schema change
** while this routine is running. Hence, we do not need to hold
** locks on the schema, we just need to make sure nobody else is
** holding them.
**
** Note that setting READ_UNCOMMITTED overrides most lock detection,
** but it does *not* override schema lock detection, so this all still
** works even if READ_UNCOMMITTED is set.
*/
for(i=0; i<db->nDb; i++) {
Btree *pBt = db->aDb[i].pBt;
if( pBt ){
assert( sqlite3BtreeHoldsMutex(pBt) );
rc = sqlite3BtreeSchemaLocked(pBt);
if( rc ){
const char *zDb = db->aDb[i].zName;
sqlite3Error(db, rc, "database schema is locked: %s", zDb);
(void)sqlite3SafetyOff(db);
testcase( db->flags & SQLITE_ReadUncommitted );
return sqlite3ApiExit(db, rc);
}
}
}
memset(&sParse, 0, sizeof(sParse));
sParse.db = db;
if( nBytes>=0 && (nBytes==0 || zSql[nBytes-1]!=0) ){
char *zSqlCopy;
int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
if( nBytes>mxLen ){
sqlite3Error(db, SQLITE_TOOBIG, "statement too long");
(void)sqlite3SafetyOff(db);
return sqlite3ApiExit(db, SQLITE_TOOBIG);
}
zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
if( zSqlCopy ){
sqlite3RunParser(&sParse, zSqlCopy, &zErrMsg);
sqlite3DbFree(db, zSqlCopy);
sParse.zTail = &zSql[sParse.zTail-zSqlCopy];
}else{
sParse.zTail = &zSql[nBytes];
}
}else{
sqlite3RunParser(&sParse, zSql, &zErrMsg);
}
if( db->mallocFailed ){
sParse.rc = SQLITE_NOMEM;
}
if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
if( sParse.checkSchema && !schemaIsValid(db) ){
sParse.rc = SQLITE_SCHEMA;
}
if( sParse.rc==SQLITE_SCHEMA ){
sqlite3ResetInternalSchema(db, 0);
}
if( db->mallocFailed ){
sParse.rc = SQLITE_NOMEM;
}
if( pzTail ){
*pzTail = sParse.zTail;
}
rc = sParse.rc;
#ifndef SQLITE_OMIT_EXPLAIN
if( rc==SQLITE_OK && sParse.pVdbe && sParse.explain ){
if( sParse.explain==2 ){
sqlite3VdbeSetNumCols(sParse.pVdbe, 3);
sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "order", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "from", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "detail", SQLITE_STATIC);
}else{
sqlite3VdbeSetNumCols(sParse.pVdbe, 8);
sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "addr", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "opcode", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "p1", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 3, COLNAME_NAME, "p2", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 4, COLNAME_NAME, "p3", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 5, COLNAME_NAME, "p4", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 6, COLNAME_NAME, "p5", SQLITE_STATIC);
sqlite3VdbeSetColName(sParse.pVdbe, 7, COLNAME_NAME, "comment", SQLITE_STATIC);
}
}
#endif
if( sqlite3SafetyOff(db) ){
rc = SQLITE_MISUSE;
}
assert( db->init.busy==0 || saveSqlFlag==0 );
if( db->init.busy==0 ){
Vdbe *pVdbe = sParse.pVdbe;
sqlite3VdbeSetSql(pVdbe, zSql, (int)(sParse.zTail-zSql), saveSqlFlag);
}
if( sParse.pVdbe && (rc!=SQLITE_OK || db->mallocFailed) ){
sqlite3VdbeFinalize(sParse.pVdbe);
assert(!(*ppStmt));
}else{
*ppStmt = (sqlite3_stmt*)sParse.pVdbe;
}
if( zErrMsg ){
sqlite3Error(db, rc, "%s", zErrMsg);
sqlite3DbFree(db, zErrMsg);
}else{
sqlite3Error(db, rc, 0);
}
rc = sqlite3ApiExit(db, rc);
assert( (rc&db->errMask)==rc );
return rc;
}
/*
** Attempt to read the database schema and initialize internal
** data structures for a single database file. The index of the
** database file is given by iDb. iDb==0 is used for the main
** database. iDb==1 should never be used. iDb>=2 is used for
** auxiliary databases. Return one of the SQLITE_ error codes to
** indicate success or failure.
*/
static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
int rc;
BtCursor *curMain;
int size;
Table *pTab;
Db *pDb;
char const *azArg[4];
int meta[10];
InitData initData;
char const *zMasterSchema;
char const *zMasterName = SCHEMA_TABLE(iDb);
/*
** The master database table has a structure like this
*/
static const char master_schema[] =
"CREATE TABLE sqlite_master(\n"
" type text,\n"
" name text,\n"
" tbl_name text,\n"
" rootpage integer,\n"
" sql text\n"
")"
;
#ifndef SQLITE_OMIT_TEMPDB
static const char temp_master_schema[] =
"CREATE TEMP TABLE sqlite_temp_master(\n"
" type text,\n"
" name text,\n"
" tbl_name text,\n"
" rootpage integer,\n"
" sql text\n"
")"
;
#else
#define temp_master_schema 0
#endif
assert( iDb>=0 && iDb<db->nDb );
assert( db->aDb[iDb].pSchema );
assert( sqlite3_mutex_held(db->mutex) );
assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
/* zMasterSchema and zInitScript are set to point at the master schema
** and initialisation script appropriate for the database being
** initialised. zMasterName is the name of the master table.
*/
if( !OMIT_TEMPDB && iDb==1 ){
zMasterSchema = temp_master_schema;
}else{
zMasterSchema = master_schema;
}
zMasterName = SCHEMA_TABLE(iDb);
/* Construct the schema tables. */
azArg[0] = zMasterName;
azArg[1] = "1";
azArg[2] = zMasterSchema;
azArg[3] = 0;
initData.db = db;
initData.iDb = iDb;
initData.rc = SQLITE_OK;
initData.pzErrMsg = pzErrMsg;
(void)sqlite3SafetyOff(db);
sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
(void)sqlite3SafetyOn(db);
if( initData.rc ){
rc = initData.rc;
goto error_out;
}
pTab = sqlite3FindTable(db, zMasterName, db->aDb[iDb].zName);
if( pTab ){
pTab->tabFlags |= TF_Readonly;
}
/* Create a cursor to hold the database open
*/
pDb = &db->aDb[iDb];
if( pDb->pBt==0 ){
if( !OMIT_TEMPDB && iDb==1 ){
DbSetProperty(db, 1, DB_SchemaLoaded);
}
return SQLITE_OK;
}
curMain = sqlite3MallocZero(sqlite3BtreeCursorSize());
if( !curMain ){
rc = SQLITE_NOMEM;
goto error_out;
}
sqlite3BtreeEnter(pDb->pBt);
rc = sqlite3BtreeCursor(pDb->pBt, MASTER_ROOT, 0, 0, curMain);
if( rc!=SQLITE_OK && rc!=SQLITE_EMPTY ){
sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
goto initone_error_out;
}
/* Get the database meta information.
**
** Meta values are as follows:
** meta[0] Schema cookie. Changes with each schema change.
** meta[1] File format of schema layer.
** meta[2] Size of the page cache.
** meta[3] Use freelist if 0. Autovacuum if greater than zero.
** meta[4] Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
** meta[5] The user cookie. Used by the application.
** meta[6] Incremental-vacuum flag.
** meta[7]
** meta[8]
** meta[9]
**
** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
** the possible values of meta[4].
*/
if( rc==SQLITE_OK ){
int i;
for(i=0; i<ArraySize(meta); i++){
rc = sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
if( rc ){
sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
goto initone_error_out;
}
}
}else{
memset(meta, 0, sizeof(meta));
}
pDb->pSchema->schema_cookie = meta[0];
/* If opening a non-empty database, check the text encoding. For the
** main database, set sqlite3.enc to the encoding of the main database.
** For an attached db, it is an error if the encoding is not the same
** as sqlite3.enc.
*/
if( meta[4] ){ /* text encoding */
if( iDb==0 ){
/* If opening the main database, set ENC(db). */
ENC(db) = (u8)meta[4];
db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
}else{
/* If opening an attached database, the encoding much match ENC(db) */
if( meta[4]!=ENC(db) ){
sqlite3SetString(pzErrMsg, db, "attached databases must use the same"
" text encoding as main database");
rc = SQLITE_ERROR;
goto initone_error_out;
}
}
}else{
DbSetProperty(db, iDb, DB_Empty);
}
pDb->pSchema->enc = ENC(db);
if( pDb->pSchema->cache_size==0 ){
size = meta[2];
if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
if( size<0 ) size = -size;
pDb->pSchema->cache_size = size;
sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
}
/*
** file_format==1 Version 3.0.0.
** file_format==2 Version 3.1.3. // ALTER TABLE ADD COLUMN
** file_format==3 Version 3.1.4. // ditto but with non-NULL defaults
** file_format==4 Version 3.3.0. // DESC indices. Boolean constants
*/
pDb->pSchema->file_format = (u8)meta[1];
if( pDb->pSchema->file_format==0 ){
pDb->pSchema->file_format = 1;
}
if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
sqlite3SetString(pzErrMsg, db, "unsupported file format");
rc = SQLITE_ERROR;
goto initone_error_out;
}
/* Ticket #2804: When we open a database in the newer file format,
** clear the legacy_file_format pragma flag so that a VACUUM will
** not downgrade the database and thus invalidate any descending
** indices that the user might have created.
*/
if( iDb==0 && meta[1]>=4 ){
db->flags &= ~SQLITE_LegacyFileFmt;
}
/* Read the schema information out of the schema tables
*/
assert( db->init.busy );
if( rc==SQLITE_EMPTY ){
/* For an empty database, there is nothing to read */
rc = SQLITE_OK;
}else{
char *zSql;
zSql = sqlite3MPrintf(db,
"SELECT name, rootpage, sql FROM '%q'.%s",
db->aDb[iDb].zName, zMasterName);
(void)sqlite3SafetyOff(db);
#ifndef SQLITE_OMIT_AUTHORIZATION
{
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
xAuth = db->xAuth;
db->xAuth = 0;
#endif
rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
#ifndef SQLITE_OMIT_AUTHORIZATION
db->xAuth = xAuth;
}
#endif
if( rc==SQLITE_OK ) rc = initData.rc;
(void)sqlite3SafetyOn(db);
sqlite3DbFree(db, zSql);
#ifndef SQLITE_OMIT_ANALYZE
if( rc==SQLITE_OK ){
sqlite3AnalysisLoad(db, iDb);
}
#endif
}
if( db->mallocFailed ){
rc = SQLITE_NOMEM;
sqlite3ResetInternalSchema(db, 0);
}
if( rc==SQLITE_OK || (db->flags&SQLITE_RecoveryMode)){
/* Black magic: If the SQLITE_RecoveryMode flag is set, then consider
** the schema loaded, even if errors occurred. In this situation the
** current sqlite3_prepare() operation will fail, but the following one
** will attempt to compile the supplied statement against whatever subset
** of the schema was loaded before the error occurred. The primary
** purpose of this is to allow access to the sqlite_master table
** even when its contents have been corrupted.
*/
DbSetProperty(db, iDb, DB_SchemaLoaded);
rc = SQLITE_OK;
}
/* Jump here for an error that occurs after successfully allocating
** curMain and calling sqlite3BtreeEnter(). For an error that occurs
** before that point, jump to error_out.
*/
initone_error_out:
sqlite3BtreeCloseCursor(curMain);
sqlite3_free(curMain);
sqlite3BtreeLeave(pDb->pBt);
error_out:
if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
db->mallocFailed = 1;
}
return rc;
}
/*
** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
*/
static int sqlite3Prepare(
sqlite3 *db, /* Database handle. */
const char *zSql, /* UTF-8 encoded SQL statement. */
int nBytes, /* Length of zSql in bytes. */
int saveSqlFlag, /* True to copy SQL text into the sqlite3_stmt */
Vdbe *pReprepare, /* VM being reprepared */
sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */
const char **pzTail /* OUT: End of parsed string */
){
Parse *pParse; /* Parsing context */
char *zErrMsg = 0; /* Error message */
int rc = SQLITE_OK; /* Result code */
int i; /* Loop counter */
/* Allocate the parsing context */
pParse = sqlite3StackAllocZero(db, sizeof(*pParse));
if( pParse==0 ){
rc = SQLITE_NOMEM;
goto end_prepare;
}
pParse->pReprepare = pReprepare;
if( sqlite3SafetyOn(db) ){
rc = SQLITE_MISUSE;
goto end_prepare;
}
assert( ppStmt && *ppStmt==0 );
assert( !db->mallocFailed );
assert( sqlite3_mutex_held(db->mutex) );
/* Check to verify that it is possible to get a read lock on all
** database schemas. The inability to get a read lock indicates that
** some other database connection is holding a write-lock, which in
** turn means that the other connection has made uncommitted changes
** to the schema.
**
** Were we to proceed and prepare the statement against the uncommitted
** schema changes and if those schema changes are subsequently rolled
** back and different changes are made in their place, then when this
** prepared statement goes to run the schema cookie would fail to detect
** the schema change. Disaster would follow.
**
** This thread is currently holding mutexes on all Btrees (because
** of the sqlite3BtreeEnterAll() in sqlite3LockAndPrepare()) so it
** is not possible for another thread to start a new schema change
** while this routine is running. Hence, we do not need to hold
** locks on the schema, we just need to make sure nobody else is
** holding them.
**
** Note that setting READ_UNCOMMITTED overrides most lock detection,
** but it does *not* override schema lock detection, so this all still
** works even if READ_UNCOMMITTED is set.
*/
for(i=0; i<db->nDb; i++) {
Btree *pBt = db->aDb[i].pBt;
if( pBt ){
assert( sqlite3BtreeHoldsMutex(pBt) );
rc = sqlite3BtreeSchemaLocked(pBt);
if( rc ){
const char *zDb = db->aDb[i].zName;
sqlite3Error(db, rc, "database schema is locked: %s", zDb);
(void)sqlite3SafetyOff(db);
testcase( db->flags & SQLITE_ReadUncommitted );
goto end_prepare;
}
}
}
sqlite3VtabUnlockList(db);
pParse->db = db;
if( nBytes>=0 && (nBytes==0 || zSql[nBytes-1]!=0) ){
char *zSqlCopy;
int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
testcase( nBytes==mxLen );
testcase( nBytes==mxLen+1 );
if( nBytes>mxLen ){
sqlite3Error(db, SQLITE_TOOBIG, "statement too long");
(void)sqlite3SafetyOff(db);
rc = sqlite3ApiExit(db, SQLITE_TOOBIG);
goto end_prepare;
}
zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
if( zSqlCopy ){
sqlite3RunParser(pParse, zSqlCopy, &zErrMsg);
sqlite3DbFree(db, zSqlCopy);
pParse->zTail = &zSql[pParse->zTail-zSqlCopy];
}else{
pParse->zTail = &zSql[nBytes];
}
}else{
sqlite3RunParser(pParse, zSql, &zErrMsg);
}
if( db->mallocFailed ){
pParse->rc = SQLITE_NOMEM;
}
if( pParse->rc==SQLITE_DONE ) pParse->rc = SQLITE_OK;
if( pParse->checkSchema ){
schemaIsValid(pParse);
}
if( pParse->rc==SQLITE_SCHEMA ){
sqlite3ResetInternalSchema(db, 0);
}
if( db->mallocFailed ){
pParse->rc = SQLITE_NOMEM;
}
if( pzTail ){
*pzTail = pParse->zTail;
}
rc = pParse->rc;
#ifndef SQLITE_OMIT_EXPLAIN
if( rc==SQLITE_OK && pParse->pVdbe && pParse->explain ){
static const char * const azColName[] = {
"addr", "opcode", "p1", "p2", "p3", "p4", "p5", "comment",
"order", "from", "detail"
};
int iFirst, mx;
if( pParse->explain==2 ){
sqlite3VdbeSetNumCols(pParse->pVdbe, 3);
iFirst = 8;
mx = 11;
}else{
sqlite3VdbeSetNumCols(pParse->pVdbe, 8);
iFirst = 0;
mx = 8;
}
for(i=iFirst; i<mx; i++){
sqlite3VdbeSetColName(pParse->pVdbe, i-iFirst, COLNAME_NAME,
azColName[i], SQLITE_STATIC);
}
}
#endif
if( sqlite3SafetyOff(db) ){
rc = SQLITE_MISUSE;
}
assert( db->init.busy==0 || saveSqlFlag==0 );
if( db->init.busy==0 ){
Vdbe *pVdbe = pParse->pVdbe;
sqlite3VdbeSetSql(pVdbe, zSql, (int)(pParse->zTail-zSql), saveSqlFlag);
}
if( pParse->pVdbe && (rc!=SQLITE_OK || db->mallocFailed) ){
sqlite3VdbeFinalize(pParse->pVdbe);
assert(!(*ppStmt));
}else{
*ppStmt = (sqlite3_stmt*)pParse->pVdbe;
}
if( zErrMsg ){
sqlite3Error(db, rc, "%s", zErrMsg);
sqlite3DbFree(db, zErrMsg);
}else{
sqlite3Error(db, rc, 0);
}
/* Delete any TriggerPrg structures allocated while parsing this statement. */
while( pParse->pTriggerPrg ){
TriggerPrg *pT = pParse->pTriggerPrg;
pParse->pTriggerPrg = pT->pNext;
sqlite3VdbeProgramDelete(db, pT->pProgram, 0);
sqlite3DbFree(db, pT);
}
end_prepare:
sqlite3StackFree(db, pParse);
rc = sqlite3ApiExit(db, rc);
assert( (rc&db->errMask)==rc );
return rc;
}
/*
** Load the content of the sqlite_stat1 and sqlite_stat2 tables. The
** contents of sqlite_stat1 are used to populate the Index.aiRowEst[]
** arrays. The contents of sqlite_stat2 are used to populate the
** Index.aSample[] arrays.
**
** If the sqlite_stat1 table is not present in the database, SQLITE_ERROR
** is returned. In this case, even if SQLITE_ENABLE_STAT2 was defined
** during compilation and the sqlite_stat2 table is present, no data is
** read from it.
**
** If SQLITE_ENABLE_STAT2 was defined during compilation and the
** sqlite_stat2 table is not present in the database, SQLITE_ERROR is
** returned. However, in this case, data is read from the sqlite_stat1
** table (if it is present) before returning.
**
** If an OOM error occurs, this function always sets db->mallocFailed.
** This means if the caller does not care about other errors, the return
** code may be ignored.
*/
int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
analysisInfo sInfo;
HashElem *i;
char *zSql;
int rc;
assert( iDb>=0 && iDb<db->nDb );
assert( db->aDb[iDb].pBt!=0 );
assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
/* Clear any prior statistics */
for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){
Index *pIdx = sqliteHashData(i);
sqlite3DefaultRowEst(pIdx);
sqlite3DeleteIndexSamples(db, pIdx);
pIdx->aSample = 0;
}
/* Check to make sure the sqlite_stat1 table exists */
sInfo.db = db;
sInfo.zDatabase = db->aDb[iDb].zName;
if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){
return SQLITE_ERROR;
}
/* Load new statistics out of the sqlite_stat1 table */
zSql = sqlite3MPrintf(db,
"SELECT tbl, idx, stat FROM %Q.sqlite_stat1", sInfo.zDatabase);
if( zSql==0 ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
sqlite3DbFree(db, zSql);
}
/* Load the statistics from the sqlite_stat2 table. */
#ifdef SQLITE_ENABLE_STAT2
if( rc==SQLITE_OK && !sqlite3FindTable(db, "sqlite_stat2", sInfo.zDatabase) ){
rc = SQLITE_ERROR;
}
if( rc==SQLITE_OK ){
sqlite3_stmt *pStmt = 0;
zSql = sqlite3MPrintf(db,
"SELECT idx,sampleno,sample FROM %Q.sqlite_stat2", sInfo.zDatabase);
if( !zSql ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
sqlite3DbFree(db, zSql);
}
if( rc==SQLITE_OK ){
while( sqlite3_step(pStmt)==SQLITE_ROW ){
char *zIndex = (char *)sqlite3_column_text(pStmt, 0);
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 sz = sizeof(IndexSample)*SQLITE_INDEX_SAMPLES;
pIdx->aSample = (IndexSample *)sqlite3DbMallocRaw(0, sz);
if( pIdx->aSample==0 ){
db->mallocFailed = 1;
break;
}
memset(pIdx->aSample, 0, sz);
}
assert( pIdx->aSample );
{
IndexSample *pSample = &pIdx->aSample[iSample];
pSample->eType = (u8)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 = (u8)n;
if( n < 1){
pSample->u.z = 0;
}else{
pSample->u.z = sqlite3DbStrNDup(0, z, n);
if( pSample->u.z==0 ){
db->mallocFailed = 1;
break;
}
}
}
}
}
}
}
rc = sqlite3_finalize(pStmt);
}
}
#endif
if( rc==SQLITE_NOMEM ){
db->mallocFailed = 1;
}
return rc;
}
