Delete the OP_VerifySchema opcode. Enhance OP_Transaction to do the schema

version checks that OP_VerifySchema used to do.

FossilOrigin-Name: 2f3376ebf13df44e6acf27cb1f07172cd8b34033

5 files changed, 75 insertions, 103 deletions

diff --git a/src/alter.c b/src/alter.c
index 9d34b07b0..67070a589 100644
--- a/src/alter.c
+++ b/src/alter.c
@@ -469,7 +469,7 @@ void sqlite3AlterRenameTable(
   }
 #endif
 
-  /* Begin a transaction and code the VerifyCookie for database iDb. 
+  /* Begin a transaction for database iDb. 
   ** Then modify the schema cookie (since the ALTER TABLE modifies the
   ** schema). Open a statement transaction if the table is a virtual
   ** table.
diff --git a/src/build.c b/src/build.c
index fa7364c3d..afd68a8f6 100644
--- a/src/build.c
+++ b/src/build.c
@@ -156,13 +156,14 @@ void sqlite3FinishCoding(Parse *pParse){
       for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
         if( (mask & pParse->cookieMask)==0 ) continue;
         sqlite3VdbeUsesBtree(v, iDb);
-        sqlite3VdbeAddOp2(v,OP_Transaction, iDb, (mask & pParse->writeMask)!=0);
-        if( db->init.busy==0 ){
-          assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
-          sqlite3VdbeAddOp3(v, OP_VerifyCookie,
-                            iDb, pParse->cookieValue[iDb],
-                            db->aDb[iDb].pSchema->iGeneration);
-        }
+        sqlite3VdbeAddOp4Int(v,
+          OP_Transaction,                    /* Opcode */
+          iDb,                               /* P1 */
+          (mask & pParse->writeMask)!=0,     /* P2 */
+          pParse->cookieValue[iDb],          /* P3 */
+          db->aDb[iDb].pSchema->iGeneration  /* P4 */
+        );
+        if( db->init.busy==0 ) sqlite3VdbeChangeP5(v, 1);
       }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
       for(i=0; i<pParse->nVtabLock; i++){
diff --git a/src/expr.c b/src/expr.c
index ee9d7877a..e417d8aad 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1584,7 +1584,7 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
     pExpr = p->pEList->a[0].pExpr;
     iCol = (i16)pExpr->iColumn;
    
-    /* Code an OP_VerifyCookie and OP_TableLock for <table>. */
+    /* Code an OP_Transaction and OP_TableLock for <table>. */
     iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
     sqlite3CodeVerifySchema(pParse, iDb);
     sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
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
 **
diff --git a/src/vdbeblob.c b/src/vdbeblob.c
index 20841c44f..0fbc1ad47 100644
--- a/src/vdbeblob.c
+++ b/src/vdbeblob.c
@@ -134,21 +134,20 @@ int sqlite3_blob_open(
   ** transaction.
   */
   static const VdbeOpList openBlob[] = {
-    {OP_Transaction, 0, 0, 0},     /* 0: Start a transaction */
-    {OP_VerifyCookie, 0, 0, 0},    /* 1: Check the schema cookie */
-    {OP_TableLock, 0, 0, 0},       /* 2: Acquire a read or write lock */
+    /* {OP_Transaction, 0, 0, 0},  // 0: Inserted separately */
+    {OP_TableLock, 0, 0, 0},       /* 1: Acquire a read or write lock */
 
     /* One of the following two instructions is replaced by an OP_Noop. */
-    {OP_OpenRead, 0, 0, 0},        /* 3: Open cursor 0 for reading */
-    {OP_OpenWrite, 0, 0, 0},       /* 4: Open cursor 0 for read/write */
-
-    {OP_Variable, 1, 1, 1},        /* 5: Push the rowid to the stack */
-    {OP_NotExists, 0, 10, 1},      /* 6: Seek the cursor */
-    {OP_Column, 0, 0, 1},          /* 7  */
-    {OP_ResultRow, 1, 0, 0},       /* 8  */
-    {OP_Goto, 0, 5, 0},            /* 9  */
-    {OP_Close, 0, 0, 0},           /* 10 */
-    {OP_Halt, 0, 0, 0},            /* 11 */
+    {OP_OpenRead, 0, 0, 0},        /* 2: Open cursor 0 for reading */
+    {OP_OpenWrite, 0, 0, 0},       /* 3: Open cursor 0 for read/write */
+
+    {OP_Variable, 1, 1, 1},        /* 4: Push the rowid to the stack */
+    {OP_NotExists, 0, 10, 1},      /* 5: Seek the cursor */
+    {OP_Column, 0, 0, 1},          /* 6  */
+    {OP_ResultRow, 1, 0, 0},       /* 7  */
+    {OP_Goto, 0, 4, 0},            /* 8  */
+    {OP_Close, 0, 0, 0},           /* 9  */
+    {OP_Halt, 0, 0, 0},            /* 10 */
   };
 
   int rc = SQLITE_OK;
@@ -261,36 +260,31 @@ int sqlite3_blob_open(
       Vdbe *v = (Vdbe *)pBlob->pStmt;
       int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
 
-      sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
-
-
-      /* Configure the OP_Transaction */
-      sqlite3VdbeChangeP1(v, 0, iDb);
-      sqlite3VdbeChangeP2(v, 0, flags);
 
-      /* Configure the OP_VerifyCookie */
-      sqlite3VdbeChangeP1(v, 1, iDb);
-      sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);
-      sqlite3VdbeChangeP3(v, 1, pTab->pSchema->iGeneration);
+      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, flags, 
+                           pTab->pSchema->schema_cookie,
+                           pTab->pSchema->iGeneration);
+      sqlite3VdbeChangeP5(v, 1);     
+      sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
 
       /* Make sure a mutex is held on the table to be accessed */
       sqlite3VdbeUsesBtree(v, iDb); 
 
       /* Configure the OP_TableLock instruction */
 #ifdef SQLITE_OMIT_SHARED_CACHE
-      sqlite3VdbeChangeToNoop(v, 2);
+      sqlite3VdbeChangeToNoop(v, 1);
 #else
-      sqlite3VdbeChangeP1(v, 2, iDb);
-      sqlite3VdbeChangeP2(v, 2, pTab->tnum);
-      sqlite3VdbeChangeP3(v, 2, flags);
-      sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
+      sqlite3VdbeChangeP1(v, 1, iDb);
+      sqlite3VdbeChangeP2(v, 1, pTab->tnum);
+      sqlite3VdbeChangeP3(v, 1, flags);
+      sqlite3VdbeChangeP4(v, 1, pTab->zName, P4_TRANSIENT);
 #endif
 
       /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
       ** parameter of the other to pTab->tnum.  */
-      sqlite3VdbeChangeToNoop(v, 4 - flags);
-      sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
-      sqlite3VdbeChangeP3(v, 3 + flags, iDb);
+      sqlite3VdbeChangeToNoop(v, 3 - flags);
+      sqlite3VdbeChangeP2(v, 2 + flags, pTab->tnum);
+      sqlite3VdbeChangeP3(v, 2 + flags, iDb);
 
       /* Configure the number of columns. Configure the cursor to
       ** think that the table has one more column than it really
@@ -299,8 +293,8 @@ int sqlite3_blob_open(
       ** we can invoke OP_Column to fill in the vdbe cursors type 
       ** and offset cache without causing any IO.
       */
-      sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
-      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
+      sqlite3VdbeChangeP4(v, 2+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
+      sqlite3VdbeChangeP2(v, 6, pTab->nCol);
       if( !db->mallocFailed ){
         pParse->nVar = 1;
         pParse->nMem = 1;