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Overview
Comment: | Avoid an excess register allocation in UPDATE, when possible. This improves speed (slightly) and reduces the code footprint. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
8658574e3f435f03a87c04f398bd0507 |
User & Date: | drh 2019-05-08 19:06:59.709 |
Context
2019-05-08
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19:32 | Simplification to the logic underlying PRAGMA case_sensitive_like. (check-in: ef0015fde4 user: drh tags: trunk) | |
19:06 | Avoid an excess register allocation in UPDATE, when possible. This improves speed (slightly) and reduces the code footprint. (check-in: 8658574e3f user: drh tags: trunk) | |
18:49 | Add tests to improve code coverage of the RBU module. (check-in: ecb56b75a0 user: dan tags: trunk) | |
Changes
Changes to src/update.c.
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151 152 153 154 155 156 157 158 159 160 161 162 163 164 | Table *pTab; /* The table to be updated */ int addrTop = 0; /* VDBE instruction address of the start of the loop */ WhereInfo *pWInfo; /* Information about the WHERE clause */ Vdbe *v; /* The virtual database engine */ Index *pIdx; /* For looping over indices */ Index *pPk; /* The PRIMARY KEY index for WITHOUT ROWID tables */ int nIdx; /* Number of indices that need updating */ int iBaseCur; /* Base cursor number */ int iDataCur; /* Cursor for the canonical data btree */ int iIdxCur; /* Cursor for the first index */ sqlite3 *db; /* The database structure */ int *aRegIdx = 0; /* Registers for to each index and the main table */ int *aXRef = 0; /* aXRef[i] is the index in pChanges->a[] of the ** an expression for the i-th column of the table. | > | 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 | Table *pTab; /* The table to be updated */ int addrTop = 0; /* VDBE instruction address of the start of the loop */ WhereInfo *pWInfo; /* Information about the WHERE clause */ Vdbe *v; /* The virtual database engine */ Index *pIdx; /* For looping over indices */ Index *pPk; /* The PRIMARY KEY index for WITHOUT ROWID tables */ int nIdx; /* Number of indices that need updating */ int nAllIdx; /* Total number of indexes */ int iBaseCur; /* Base cursor number */ int iDataCur; /* Cursor for the canonical data btree */ int iIdxCur; /* Cursor for the first index */ sqlite3 *db; /* The database structure */ int *aRegIdx = 0; /* Registers for to each index and the main table */ int *aXRef = 0; /* aXRef[i] is the index in pChanges->a[] of the ** an expression for the i-th column of the table. |
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351 352 353 354 355 356 357 | hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey); /* There is one entry in the aRegIdx[] array for each index on the table ** being updated. Fill in aRegIdx[] with a register number that will hold ** the key for accessing each index. */ if( onError==OE_Replace ) bReplace = 1; | | | | | > > > > > > | | 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 | hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey); /* There is one entry in the aRegIdx[] array for each index on the table ** being updated. Fill in aRegIdx[] with a register number that will hold ** the key for accessing each index. */ if( onError==OE_Replace ) bReplace = 1; for(nAllIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nAllIdx++){ int reg; if( chngKey || hasFK>1 || pIdx==pPk || indexWhereClauseMightChange(pIdx,aXRef,chngRowid) ){ reg = ++pParse->nMem; pParse->nMem += pIdx->nColumn; }else{ reg = 0; for(i=0; i<pIdx->nKeyCol; i++){ if( indexColumnIsBeingUpdated(pIdx, i, aXRef, chngRowid) ){ reg = ++pParse->nMem; pParse->nMem += pIdx->nColumn; if( onError==OE_Default && pIdx->onError==OE_Replace ){ bReplace = 1; } break; } } } if( reg==0 ) aToOpen[nAllIdx+1] = 0; aRegIdx[nAllIdx] = reg; } aRegIdx[nAllIdx] = ++pParse->nMem; /* Register storing the table record */ if( bReplace ){ /* If REPLACE conflict resolution might be invoked, open cursors on all ** indexes in case they are needed to delete records. */ memset(aToOpen, 1, nIdx+1); } /* Begin generating code. */ v = sqlite3GetVdbe(pParse); if( v==0 ) goto update_cleanup; if( pParse->nested==0 ) sqlite3VdbeCountChanges(v); sqlite3BeginWriteOperation(pParse, pTrigger || hasFK, iDb); /* Allocate required registers. */ if( !IsVirtual(pTab) ){ /* For now, regRowSet and aRegIdx[nAllIdx] share the same register. ** If regRowSet turns out to be needed, then aRegIdx[nAllIdx] will be ** reallocated. aRegIdx[nAllIdx] is the register in which the main ** table record is written. regRowSet holds the RowSet for the ** two-pass update algorithm. */ assert( aRegIdx[nAllIdx]==pParse->nMem ); regRowSet = aRegIdx[nAllIdx]; regOldRowid = regNewRowid = ++pParse->nMem; if( chngPk || pTrigger || hasFK ){ regOld = pParse->nMem + 1; pParse->nMem += pTab->nCol; } if( chngKey || pTrigger || hasFK ){ regNewRowid = ++pParse->nMem; |
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519 520 521 522 523 524 525 526 527 528 529 530 531 532 | if( HasRowid(pTab) ){ /* Read the rowid of the current row of the WHERE scan. In ONEPASS_OFF ** mode, write the rowid into the FIFO. In either of the one-pass modes, ** leave it in register regOldRowid. */ sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid); if( eOnePass==ONEPASS_OFF ){ sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid); } }else{ /* Read the PK of the current row into an array of registers. In ** ONEPASS_OFF mode, serialize the array into a record and store it in ** the ephemeral table. Or, in ONEPASS_SINGLE or MULTI mode, change ** the OP_OpenEphemeral instruction to a Noop (the ephemeral table | > > | 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 | if( HasRowid(pTab) ){ /* Read the rowid of the current row of the WHERE scan. In ONEPASS_OFF ** mode, write the rowid into the FIFO. In either of the one-pass modes, ** leave it in register regOldRowid. */ sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid); if( eOnePass==ONEPASS_OFF ){ /* We need to use regRowSet, so reallocate aRegIdx[nAllIdx] */ aRegIdx[nAllIdx] = ++pParse->nMem; sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid); } }else{ /* Read the PK of the current row into an array of registers. In ** ONEPASS_OFF mode, serialize the array into a record and store it in ** the ephemeral table. Or, in ONEPASS_SINGLE or MULTI mode, change ** the OP_OpenEphemeral instruction to a Noop (the ephemeral table |
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