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Small size and performance in the OP_Column opcode.

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FossilOrigin-Name: 2cf3f3de8a48465bd6b0af7763bfe905f3bb0151488f63c9ecc3147bcb345094
This commit is contained in:
drh
2017-08-15 14:14:36 +00:00
parent 352a35abf5
commit 6cd8c8c57a
3 changed files with 13 additions and 17 deletions
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16
src/vdbe.c
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@@ -2388,7 +2388,6 @@ case OP_Column: {
const u8 *zEndHdr; /* Pointer to first byte after the header */
u32 offset; /* Offset into the data */
u64 offset64; /* 64-bit offset */
u32 avail; /* Number of bytes of available data */
u32 t; /* A type code from the record header */
Mem *pReg; /* PseudoTable input register */
@@ -2419,7 +2418,7 @@ case OP_Column: {
pReg = &aMem[pC->uc.pseudoTableReg];
assert( pReg->flags & MEM_Blob );
assert( memIsValid(pReg) );
pC->payloadSize = pC->szRow = avail = pReg->n;
pC->payloadSize = pC->szRow = pReg->n;
pC->aRow = (u8*)pReg->z;
}else{
sqlite3VdbeMemSetNull(pDest);
@@ -2431,14 +2430,11 @@ case OP_Column: {
assert( pCrsr );
assert( sqlite3BtreeCursorIsValid(pCrsr) );
pC->payloadSize = sqlite3BtreePayloadSize(pCrsr);
pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &avail);
assert( avail<=65536 ); /* Maximum page size is 64KiB */
if( pC->payloadSize <= (u32)avail ){
pC->szRow = pC->payloadSize;
}else if( pC->payloadSize > (u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &pC->szRow);
assert( pC->szRow<=pC->payloadSize );
assert( pC->szRow<=65536 ); /* Maximum page size is 64KiB */
if( pC->payloadSize > (u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
goto too_big;
}else{
pC->szRow = avail;
}
}
pC->cacheStatus = p->cacheCtr;
@@ -2447,7 +2443,7 @@ case OP_Column: {
aOffset[0] = offset;
if( avail<offset ){ /*OPTIMIZATION-IF-FALSE*/
if( pC->szRow<offset ){ /*OPTIMIZATION-IF-FALSE*/
/* pC->aRow does not have to hold the entire row, but it does at least
** need to cover the header of the record. If pC->aRow does not contain
** the complete header, then set it to zero, forcing the header to be