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Delete the OP_VerifySchema opcode. Enhance OP_Transaction to do the schema

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version checks that OP_VerifySchema used to do.

FossilOrigin-Name: 2f3376ebf13df44e6acf27cb1f07172cd8b34033
This commit is contained in:
drh
2014-02-06 23:56:27 +00:00
parent 0211d8bca4
commit b22f7c831f
7 changed files with 85 additions and 113 deletions
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99
src/vdbe.c
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@@ -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 If such a query is out-of-date, we do not want to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
**