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Overview
| Comment: | Avoid many unnecessary calls to sqlite3ReadSchema() and sqlite3Init() when the schema is known to be valid already. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
58cf812fd81329e82b3fdd61b7ad2040 |
| User & Date: | drh 2018-04-25 12:01:45 |
Context
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2018-04-25
| ||
| 13:27 | Add the new SQLITE_SHELL_INIT_PROC compile-time entry point to the CLI. This is needed to work around the tighter sqlite3_config() constraints now in the CLI. (check-in: 3bcdbccf user: drh tags: trunk) | |
| 12:01 | Avoid many unnecessary calls to sqlite3ReadSchema() and sqlite3Init() when the schema is known to be valid already. (check-in: 58cf812f user: drh tags: trunk) | |
| 10:30 | Add an assert() to ensure that schema mutexes are held prior to accessing the DB_SchemaLoaded flag inside of sqlite3Init(). (check-in: d8b46290 user: drh tags: trunk) | |
Changes
Changes to src/attach.c.
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}
assert( pVfs );
flags |= SQLITE_OPEN_MAIN_DB;
rc = sqlite3BtreeOpen(pVfs, zPath, db, &pNew->pBt, 0, flags);
sqlite3_free( zPath );
db->nDb++;
}
db->skipBtreeMutex = 0;
if( rc==SQLITE_CONSTRAINT ){
rc = SQLITE_ERROR;
zErrDyn = sqlite3MPrintf(db, "database is already attached");
}else if( rc==SQLITE_OK ){
Pager *pPager;
pNew->pSchema = sqlite3SchemaGet(db, pNew->pBt);
if( !pNew->pSchema ){
................................................................................
** If this fails, or if opening the file failed, then close the file and
** remove the entry from the db->aDb[] array. i.e. put everything back the
** way we found it.
*/
if( rc==SQLITE_OK ){
sqlite3BtreeEnterAll(db);
db->init.iDb = 0;
rc = sqlite3Init(db, &zErrDyn);
sqlite3BtreeLeaveAll(db);
assert( zErrDyn==0 || rc!=SQLITE_OK );
}
#ifdef SQLITE_USER_AUTHENTICATION
if( rc==SQLITE_OK ){
u8 newAuth = 0;
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}
assert( pVfs );
flags |= SQLITE_OPEN_MAIN_DB;
rc = sqlite3BtreeOpen(pVfs, zPath, db, &pNew->pBt, 0, flags);
sqlite3_free( zPath );
db->nDb++;
}
db->noSharedCache = 0;
if( rc==SQLITE_CONSTRAINT ){
rc = SQLITE_ERROR;
zErrDyn = sqlite3MPrintf(db, "database is already attached");
}else if( rc==SQLITE_OK ){
Pager *pPager;
pNew->pSchema = sqlite3SchemaGet(db, pNew->pBt);
if( !pNew->pSchema ){
................................................................................
** If this fails, or if opening the file failed, then close the file and
** remove the entry from the db->aDb[] array. i.e. put everything back the
** way we found it.
*/
if( rc==SQLITE_OK ){
sqlite3BtreeEnterAll(db);
db->init.iDb = 0;
db->mDbFlags &= ~(DBFLAG_SchemaKnownOk);
rc = sqlite3Init(db, &zErrDyn);
sqlite3BtreeLeaveAll(db);
assert( zErrDyn==0 || rc!=SQLITE_OK );
}
#ifdef SQLITE_USER_AUTHENTICATION
if( rc==SQLITE_OK ){
u8 newAuth = 0;
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Changes to src/btmutex.c.
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for(i=0; i<db->nDb; i++){
p = db->aDb[i].pBt;
if( p && p->sharable ){
sqlite3BtreeEnter(p);
skipOk = 0;
}
}
db->skipBtreeMutex = skipOk;
}
void sqlite3BtreeEnterAll(sqlite3 *db){
if( db->skipBtreeMutex==0 ) btreeEnterAll(db);
}
static void SQLITE_NOINLINE btreeLeaveAll(sqlite3 *db){
int i;
Btree *p;
assert( sqlite3_mutex_held(db->mutex) );
for(i=0; i<db->nDb; i++){
p = db->aDb[i].pBt;
if( p ) sqlite3BtreeLeave(p);
}
}
void sqlite3BtreeLeaveAll(sqlite3 *db){
if( db->skipBtreeMutex==0 ) btreeLeaveAll(db);
}
#ifndef NDEBUG
/*
** Return true if the current thread holds the database connection
** mutex and all required BtShared mutexes.
**
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for(i=0; i<db->nDb; i++){
p = db->aDb[i].pBt;
if( p && p->sharable ){
sqlite3BtreeEnter(p);
skipOk = 0;
}
}
db->noSharedCache = skipOk;
}
void sqlite3BtreeEnterAll(sqlite3 *db){
if( db->noSharedCache==0 ) btreeEnterAll(db);
}
static void SQLITE_NOINLINE btreeLeaveAll(sqlite3 *db){
int i;
Btree *p;
assert( sqlite3_mutex_held(db->mutex) );
for(i=0; i<db->nDb; i++){
p = db->aDb[i].pBt;
if( p ) sqlite3BtreeLeave(p);
}
}
void sqlite3BtreeLeaveAll(sqlite3 *db){
if( db->noSharedCache==0 ) btreeLeaveAll(db);
}
#ifndef NDEBUG
/*
** Return true if the current thread holds the database connection
** mutex and all required BtShared mutexes.
**
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Changes to src/build.c.
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Table *sqlite3LocateTable(
Parse *pParse, /* context in which to report errors */
u32 flags, /* LOCATE_VIEW or LOCATE_NOERR */
const char *zName, /* Name of the table we are looking for */
const char *zDbase /* Name of the database. Might be NULL */
){
Table *p;
/* Read the database schema. If an error occurs, leave an error message
** and code in pParse and return NULL. */
if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
return 0;
}
p = sqlite3FindTable(pParse->db, zName, zDbase);
if( p==0 ){
const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( sqlite3FindDbName(pParse->db, zDbase)<1 ){
/* If zName is the not the name of a table in the schema created using
** CREATE, then check to see if it is the name of an virtual table that
** can be an eponymous virtual table. */
Module *pMod = (Module*)sqlite3HashFind(&pParse->db->aModule, zName);
if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
pMod = sqlite3PragmaVtabRegister(pParse->db, zName);
}
if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
return pMod->pEpoTab;
}
}
#endif
if( (flags & LOCATE_NOERR)==0 ){
................................................................................
int i;
assert( iDb<db->nDb );
if( iDb>=0 ){
assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
DbSetProperty(db, iDb, DB_ResetWanted);
DbSetProperty(db, 1, DB_ResetWanted);
}
if( db->nSchemaLock==0 ){
for(i=0; i<db->nDb; i++){
if( DbHasProperty(db, i, DB_ResetWanted) ){
sqlite3SchemaClear(db->aDb[i].pSchema);
}
................................................................................
assert( db->nSchemaLock==0 );
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.
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Table *sqlite3LocateTable(
Parse *pParse, /* context in which to report errors */
u32 flags, /* LOCATE_VIEW or LOCATE_NOERR */
const char *zName, /* Name of the table we are looking for */
const char *zDbase /* Name of the database. Might be NULL */
){
Table *p;
sqlite3 *db = pParse->db;
/* Read the database schema. If an error occurs, leave an error message
** and code in pParse and return NULL. */
if( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0
&& SQLITE_OK!=sqlite3ReadSchema(pParse)
){
return 0;
}
p = sqlite3FindTable(db, zName, zDbase);
if( p==0 ){
const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( sqlite3FindDbName(db, zDbase)<1 ){
/* If zName is the not the name of a table in the schema created using
** CREATE, then check to see if it is the name of an virtual table that
** can be an eponymous virtual table. */
Module *pMod = (Module*)sqlite3HashFind(&db->aModule, zName);
if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
pMod = sqlite3PragmaVtabRegister(db, zName);
}
if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
return pMod->pEpoTab;
}
}
#endif
if( (flags & LOCATE_NOERR)==0 ){
................................................................................
int i;
assert( iDb<db->nDb );
if( iDb>=0 ){
assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
DbSetProperty(db, iDb, DB_ResetWanted);
DbSetProperty(db, 1, DB_ResetWanted);
db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
}
if( db->nSchemaLock==0 ){
for(i=0; i<db->nDb; i++){
if( DbHasProperty(db, i, DB_ResetWanted) ){
sqlite3SchemaClear(db->aDb[i].pSchema);
}
................................................................................
assert( db->nSchemaLock==0 );
for(i=0; i<db->nDb; i++){
Db *pDb = &db->aDb[i];
if( pDb->pSchema ){
sqlite3SchemaClear(pDb->pSchema);
}
}
db->mDbFlags &= ~(DBFLAG_SchemaChange|DBFLAG_SchemaKnownOk);
sqlite3VtabUnlockList(db);
sqlite3BtreeLeaveAll(db);
sqlite3CollapseDatabaseArray(db);
}
/*
** This routine is called when a commit occurs.
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Changes to src/prepare.c.
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Db *pDb; char const *azArg[4]; int meta[5]; InitData initData; const char *zMasterName; int openedTransaction = 0; 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) ); db->init.busy = 1; ................................................................................ */ int sqlite3ReadSchema(Parse *pParse){ int rc = SQLITE_OK; sqlite3 *db = pParse->db; assert( sqlite3_mutex_held(db->mutex) ); if( !db->init.busy ){ rc = sqlite3Init(db, &pParse->zErrMsg); } if( rc!=SQLITE_OK ){ pParse->rc = rc; pParse->nErr++; } return rc; } /* ** Check schema cookies in all databases. If any cookie is out |
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Db *pDb; char const *azArg[4]; int meta[5]; InitData initData; const char *zMasterName; int openedTransaction = 0; assert( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 ); 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) ); db->init.busy = 1; ................................................................................ */ int sqlite3ReadSchema(Parse *pParse){ int rc = SQLITE_OK; sqlite3 *db = pParse->db; assert( sqlite3_mutex_held(db->mutex) ); if( !db->init.busy ){ rc = sqlite3Init(db, &pParse->zErrMsg); if( rc!=SQLITE_OK ){ pParse->rc = rc; pParse->nErr++; }else if( db->noSharedCache ){ db->mDbFlags |= DBFLAG_SchemaKnownOk; } } return rc; } /* ** Check schema cookies in all databases. If any cookie is out |
Changes to src/sqliteInt.h.
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u8 bBenignMalloc; /* Do not require OOMs if true */ u8 dfltLockMode; /* Default locking-mode for attached dbs */ signed char nextAutovac; /* Autovac setting after VACUUM if >=0 */ u8 suppressErr; /* Do not issue error messages if true */ u8 vtabOnConflict; /* Value to return for s3_vtab_on_conflict() */ u8 isTransactionSavepoint; /* True if the outermost savepoint is a TS */ u8 mTrace; /* zero or more SQLITE_TRACE flags */ u8 skipBtreeMutex; /* True if no shared-cache backends */ u8 nSqlExec; /* Number of pending OP_SqlExec opcodes */ int nextPagesize; /* Pagesize after VACUUM if >0 */ u32 magic; /* Magic number for detect library misuse */ int nChange; /* Value returned by sqlite3_changes() */ int nTotalChange; /* Value returned by sqlite3_total_changes() */ int aLimit[SQLITE_N_LIMIT]; /* Limits */ int nMaxSorterMmap; /* Maximum size of regions mapped by sorter */ ................................................................................ /* ** 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 */ |
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u8 bBenignMalloc; /* Do not require OOMs if true */ u8 dfltLockMode; /* Default locking-mode for attached dbs */ signed char nextAutovac; /* Autovac setting after VACUUM if >=0 */ u8 suppressErr; /* Do not issue error messages if true */ u8 vtabOnConflict; /* Value to return for s3_vtab_on_conflict() */ u8 isTransactionSavepoint; /* True if the outermost savepoint is a TS */ u8 mTrace; /* zero or more SQLITE_TRACE flags */ u8 noSharedCache; /* True if no shared-cache backends */ u8 nSqlExec; /* Number of pending OP_SqlExec opcodes */ int nextPagesize; /* Pagesize after VACUUM if >0 */ u32 magic; /* Magic number for detect library misuse */ int nChange; /* Value returned by sqlite3_changes() */ int nTotalChange; /* Value returned by sqlite3_total_changes() */ int aLimit[SQLITE_N_LIMIT]; /* Limits */ int nMaxSorterMmap; /* Maximum size of regions mapped by sorter */ ................................................................................ /* ** 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 */ #define DBFLAG_SchemaKnownOk 0x0008 /* Schema is known to be valid */ /* ** 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 */ |