diff options
Diffstat (limited to 'src/vdbe.c')
-rw-r--r-- | src/vdbe.c | 99 |
1 files changed, 38 insertions, 61 deletions
diff --git a/src/vdbe.c b/src/vdbe.c index 037b02f12..7c8cfe13d 100644 --- a/src/vdbe.c +++ b/src/vdbe.c @@ -2946,7 +2946,7 @@ case OP_AutoCommit: { break; } -/* Opcode: Transaction P1 P2 * * * +/* Opcode: Transaction P1 P2 P3 P4 P5 ** ** Begin a transaction. The transaction ends when a Commit or Rollback ** opcode is encountered. Depending on the ON CONFLICT setting, the @@ -2976,9 +2976,17 @@ case OP_AutoCommit: { ** will automatically commit when the VDBE halts. ** ** If P2 is zero, then a read-lock is obtained on the database file. +** +** If P5!=0 then this opcode also checks the schema cookie against P3 +** and the schema generation counter against P4. +** The cookie changes its value whenever the database schema changes. +** This operation is used to detect when that the cookie has changed +** and that the current process needs to reread the schema. */ case OP_Transaction: { Btree *pBt; + int iMeta; + int iGen; assert( p->bIsReader ); assert( p->readOnly==0 || pOp->p2==0 ); @@ -3022,6 +3030,35 @@ case OP_Transaction: { p->nStmtDefCons = db->nDeferredCons; p->nStmtDefImmCons = db->nDeferredImmCons; } + + /* Gather the schema version number for checking */ + sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&iMeta); + iGen = db->aDb[pOp->p1].pSchema->iGeneration; + }else{ + iGen = iMeta = 0; + } + assert( pOp->p5==0 || pOp->p4type==P4_INT32 ); + if( pOp->p5 && (iMeta!=pOp->p3 || iGen!=pOp->p4.i) ){ + sqlite3DbFree(db, p->zErrMsg); + p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed"); + /* If the schema-cookie from the database file matches the cookie + ** stored with the in-memory representation of the schema, do + ** not reload the schema from the database file. + ** + ** If virtual-tables are in use, this is not just an optimization. + ** Often, v-tables store their data in other SQLite tables, which + ** are queried from within xNext() and other v-table methods using + ** prepared queries. If such a query is out-of-date, we do not want to + ** discard the database schema, as the user code implementing the + ** v-table would have to be ready for the sqlite3_vtab structure itself + ** to be invalidated whenever sqlite3_step() is called from within + ** a v-table method. + */ + if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){ + sqlite3ResetOneSchema(db, pOp->p1); + } + p->expired = 1; + rc = SQLITE_SCHEMA; } break; } @@ -3096,66 +3133,6 @@ case OP_SetCookie: { /* in3 */ break; } -/* Opcode: VerifyCookie P1 P2 P3 * * -** -** Check the value of global database parameter number 0 (the -** schema version) and make sure it is equal to P2 and that the -** generation counter on the local schema parse equals P3. -** -** P1 is the database number which is 0 for the main database file -** and 1 for the file holding temporary tables and some higher number -** for auxiliary databases. -** -** The cookie changes its value whenever the database schema changes. -** This operation is used to detect when that the cookie has changed -** and that the current process needs to reread the schema. -** -** Either a transaction needs to have been started or an OP_Open needs -** to be executed (to establish a read lock) before this opcode is -** invoked. -*/ -case OP_VerifyCookie: { - int iMeta; - int iGen; - Btree *pBt; - - assert( pOp->p1>=0 && pOp->p1<db->nDb ); - assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 ); - assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) ); - assert( p->bIsReader ); - pBt = db->aDb[pOp->p1].pBt; - if( pBt ){ - sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&iMeta); - iGen = db->aDb[pOp->p1].pSchema->iGeneration; - }else{ - iGen = iMeta = 0; - } - if( iMeta!=pOp->p2 || iGen!=pOp->p3 ){ - sqlite3DbFree(db, p->zErrMsg); - p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed"); - /* If the schema-cookie from the database file matches the cookie - ** stored with the in-memory representation of the schema, do - ** not reload the schema from the database file. - ** - ** If virtual-tables are in use, this is not just an optimization. - ** Often, v-tables store their data in other SQLite tables, which - ** are queried from within xNext() and other v-table methods using - ** prepared queries. If such a query is out-of-date, we do not want to - ** discard the database schema, as the user code implementing the - ** v-table would have to be ready for the sqlite3_vtab structure itself - ** to be invalidated whenever sqlite3_step() is called from within - ** a v-table method. - */ - if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){ - sqlite3ResetOneSchema(db, pOp->p1); - } - - p->expired = 1; - rc = SQLITE_SCHEMA; - } - break; -} - /* Opcode: OpenRead P1 P2 P3 P4 P5 ** Synopsis: root=P2 iDb=P3 ** |