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Overview
| Comment: | Small size and performance improvement in the OP_Column opcode. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
2cf3f3de8a48465bd6b0af7763bfe905 |
| User & Date: | drh 2017-08-15 14:14:36 |
| Original Comment: | Small size and performance in the OP_Column opcode. |
Context
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2017-08-16
| ||
| 11:04 | Performance improvement in the OP_Column opcode. (check-in: dc98a92f user: drh tags: trunk) | |
|
2017-08-15
| ||
| 14:14 | Small size and performance improvement in the OP_Column opcode. (check-in: 2cf3f3de user: drh tags: trunk) | |
| 03:46 | Btree optimization: New field BtCursor.pPage that points to the current page, saving a single pointer dereference on each access. (check-in: 373b71d1 user: drh tags: trunk) | |
Changes
Changes to src/vdbe.c.
2384 2384 Mem *pDest; /* Where to write the extracted value */ 2385 2385 Mem sMem; /* For storing the record being decoded */ 2386 2386 const u8 *zData; /* Part of the record being decoded */ 2387 2387 const u8 *zHdr; /* Next unparsed byte of the header */ 2388 2388 const u8 *zEndHdr; /* Pointer to first byte after the header */ 2389 2389 u32 offset; /* Offset into the data */ 2390 2390 u64 offset64; /* 64-bit offset */ 2391 - u32 avail; /* Number of bytes of available data */ 2392 2391 u32 t; /* A type code from the record header */ 2393 2392 Mem *pReg; /* PseudoTable input register */ 2394 2393 2395 2394 pC = p->apCsr[pOp->p1]; 2396 2395 p2 = pOp->p2; 2397 2396 2398 2397 /* If the cursor cache is stale (meaning it is not currently point at ................................................................................ 2415 2414 if( pC->cacheStatus!=p->cacheCtr ){ /*OPTIMIZATION-IF-FALSE*/ 2416 2415 if( pC->nullRow ){ 2417 2416 if( pC->eCurType==CURTYPE_PSEUDO ){ 2418 2417 assert( pC->uc.pseudoTableReg>0 ); 2419 2418 pReg = &aMem[pC->uc.pseudoTableReg]; 2420 2419 assert( pReg->flags & MEM_Blob ); 2421 2420 assert( memIsValid(pReg) ); 2422 - pC->payloadSize = pC->szRow = avail = pReg->n; 2421 + pC->payloadSize = pC->szRow = pReg->n; 2423 2422 pC->aRow = (u8*)pReg->z; 2424 2423 }else{ 2425 2424 sqlite3VdbeMemSetNull(pDest); 2426 2425 goto op_column_out; 2427 2426 } 2428 2427 }else{ 2429 2428 pCrsr = pC->uc.pCursor; 2430 2429 assert( pC->eCurType==CURTYPE_BTREE ); 2431 2430 assert( pCrsr ); 2432 2431 assert( sqlite3BtreeCursorIsValid(pCrsr) ); 2433 2432 pC->payloadSize = sqlite3BtreePayloadSize(pCrsr); 2434 - pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &avail); 2435 - assert( avail<=65536 ); /* Maximum page size is 64KiB */ 2436 - if( pC->payloadSize <= (u32)avail ){ 2437 - pC->szRow = pC->payloadSize; 2438 - }else if( pC->payloadSize > (u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){ 2433 + pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &pC->szRow); 2434 + assert( pC->szRow<=pC->payloadSize ); 2435 + assert( pC->szRow<=65536 ); /* Maximum page size is 64KiB */ 2436 + if( pC->payloadSize > (u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){ 2439 2437 goto too_big; 2440 - }else{ 2441 - pC->szRow = avail; 2442 2438 } 2443 2439 } 2444 2440 pC->cacheStatus = p->cacheCtr; 2445 2441 pC->iHdrOffset = getVarint32(pC->aRow, offset); 2446 2442 pC->nHdrParsed = 0; 2447 2443 aOffset[0] = offset; 2448 2444 2449 2445 2450 - if( avail<offset ){ /*OPTIMIZATION-IF-FALSE*/ 2446 + if( pC->szRow<offset ){ /*OPTIMIZATION-IF-FALSE*/ 2451 2447 /* pC->aRow does not have to hold the entire row, but it does at least 2452 2448 ** need to cover the header of the record. If pC->aRow does not contain 2453 2449 ** the complete header, then set it to zero, forcing the header to be 2454 2450 ** dynamically allocated. */ 2455 2451 pC->aRow = 0; 2456 2452 pC->szRow = 0; 2457 2453