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Overview
| Comment: | Tweaks to the generated VDBE code to make it a little easier to follow. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
129217ee91782ec77ff82661753ae5be |
| User & Date: | drh 2014-02-08 13:12:19 |
Context
|
2014-02-08
| ||
| 13:24 | Fix a harmless compiler warning in VS2013. (check-in: 83116ee3 user: drh tags: trunk) | |
| 13:12 | Tweaks to the generated VDBE code to make it a little easier to follow. (check-in: 129217ee user: drh tags: trunk) | |
| 04:24 | Enable constant expression factoring even if no tables are read and no transaction is started. (check-in: a45b8771 user: drh tags: trunk) | |
Changes
Changes to src/select.c.
4533 4533 i = -1; 4534 4534 }else if( pTabList->nSrc==1 4535 4535 && OptimizationEnabled(db, SQLITE_SubqCoroutine) 4536 4536 ){ 4537 4537 /* Implement a co-routine that will return a single row of the result 4538 4538 ** set on each invocation. 4539 4539 */ 4540 - int addrTop; 4540 + int addrTop = sqlite3VdbeCurrentAddr(v)+1; 4541 4541 pItem->regReturn = ++pParse->nMem; 4542 - sqlite3VdbeAddOp0(v, OP_Goto); 4543 - addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor); 4542 + sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->regReturn, 0, addrTop); 4543 + VdbeComment((v, "%s", pItem->pTab->zName)); 4544 + sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor); 4544 4545 sqlite3VdbeChangeP5(v, 1); 4545 - VdbeComment((v, "coroutine %s", pItem->pTab->zName)); 4546 4546 pItem->addrFillSub = addrTop; 4547 4547 sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn); 4548 4548 explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId); 4549 4549 sqlite3Select(pParse, pSub, &dest); 4550 4550 pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow; 4551 4551 pItem->viaCoroutine = 1; 4552 4552 sqlite3VdbeChangeP2(v, addrTop, dest.iSdst); ................................................................................ 4563 4563 int topAddr; 4564 4564 int onceAddr = 0; 4565 4565 int retAddr; 4566 4566 assert( pItem->addrFillSub==0 ); 4567 4567 pItem->regReturn = ++pParse->nMem; 4568 4568 topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn); 4569 4569 pItem->addrFillSub = topAddr+1; 4570 - VdbeNoopComment((v, "materialize %s", pItem->pTab->zName)); 4571 4570 if( pItem->isCorrelated==0 ){ 4572 4571 /* If the subquery is not correlated and if we are not inside of 4573 4572 ** a trigger, then we only need to compute the value of the subquery 4574 4573 ** once. */ 4575 4574 onceAddr = sqlite3CodeOnce(pParse); 4575 + VdbeComment((v, "materialize \"%s\"", pItem->pTab->zName)); 4576 + }else{ 4577 + VdbeNoopComment((v, "materialize \"%s\"", pItem->pTab->zName)); 4576 4578 } 4577 4579 sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor); 4578 4580 explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId); 4579 4581 sqlite3Select(pParse, pSub, &dest); 4580 4582 pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow; 4581 4583 if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr); 4582 4584 retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
Changes to src/where.c.
2783 2783 } 2784 2784 2785 2785 /* Special case of a FROM clause subquery implemented as a co-routine */ 2786 2786 if( pTabItem->viaCoroutine ){ 2787 2787 int regYield = pTabItem->regReturn; 2788 2788 sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub); 2789 2789 pLevel->p2 = sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk); 2790 - VdbeComment((v, "next row of co-routine %s", pTabItem->pTab->zName)); 2790 + VdbeComment((v, "next row of \"%s\"", pTabItem->pTab->zName)); 2791 2791 pLevel->op = OP_Goto; 2792 2792 }else 2793 2793 2794 2794 #ifndef SQLITE_OMIT_VIRTUALTABLE 2795 2795 if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){ 2796 2796 /* Case 1: The table is a virtual-table. Use the VFilter and VNext 2797 2797 ** to access the data.