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Overview
| Comment: | This change turned out to the code slower. Side track it. Was: Tweaks to the OP_Column opcode for clarity of presentation. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | mistake |
| Files: | files | file ages | folders |
| SHA1: |
4d516240d2e465b21f8e31293b987731 |
| User & Date: | drh 2012-03-28 15:44:11.186 |
| Original Comment: | Futher tweaks to the OP_Column opcode for clarity of presentation. |
Context
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2012-03-28
| ||
| 15:44 | This change turned out to the code slower. Side track it. Was: Tweaks to the OP_Column opcode for clarity of presentation. (Closed-Leaf check-in: 4d516240d2 user: drh tags: mistake) | |
| 13:41 | Improvements to comments. Minor changes to code in the hot path of OP_Column - with the hope of get a few cycles of performance improvement. (check-in: ca09310343 user: drh tags: faster-typeof-and-length) | |
Changes
Changes to src/vdbe.c.
| ︙ | ︙ | |||
2376 2377 2378 2379 2380 2381 2382 2383 2384 |
** deserialize the value from the record. If aOffset[p2] is zero,
** then there are not enough fields in the record to satisfy the
** request. In this case, set the value NULL or to P4 if P4 is
** a pointer to a Mem object.
*/
if( aOffset[p2] ){
assert( rc==SQLITE_OK );
if( zRec ){
VdbeMemRelease(pDest);
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** deserialize the value from the record. If aOffset[p2] is zero,
** then there are not enough fields in the record to satisfy the
** request. In this case, set the value NULL or to P4 if P4 is
** a pointer to a Mem object.
*/
if( aOffset[p2] ){
assert( rc==SQLITE_OK );
t = aType[p2];
if( zRec ){
VdbeMemRelease(pDest);
zData = &zRec[aOffset[p2]];
}else if(
(pOp->p5 & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG))!=0
&& ((t>=12 && (t&1)==0) || (pOp->p5 & OPFLAG_TYPEOFARG)!=0)
){
/* Content is irrelevant for the typeof() function and for
** the length(X) function if X is a blob. So we might as well use
** bogus content rather than reading content from disk. NULL works
** for text and blob and whatever is in the payloadSize64 variable
** will work for everything else. */
zData = t<12 ? (char*)&payloadSize64 : 0;
}else{
len = sqlite3VdbeSerialTypeLen(t);
sqlite3VdbeMemMove(&sMem, pDest);
rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex,
&sMem);
if( rc!=SQLITE_OK ){
goto op_column_out;
}
zData = sMem.z;
}
sqlite3VdbeSerialGet((u8*)zData, t, pDest);
pDest->enc = encoding;
}else{
if( pOp->p4type==P4_MEM ){
sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static);
}else{
MemSetTypeFlag(pDest, MEM_Null);
}
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| ︙ | ︙ |