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Overview
| Comment: | Minor changes to the core of OP_Column for performance and to clarify the critical path. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | faster-typeof-and-length |
| Files: | files | file ages | folders |
| SHA1: |
868394761e41b7483a5874426ee052df |
| User & Date: | drh 2012-03-28 16:14:50 |
Context
|
2012-03-28
| ||
| 16:22 | Avoid loading overflow pages just to satisfy typeof() or length() functions if the correct result can be computed without the extra page fetches. (check-in: 0733c98c user: drh tags: trunk) | |
| 16:14 | Minor changes to the core of OP_Column for performance and to clarify the critical path. (Closed-Leaf check-in: 86839476 user: drh tags: faster-typeof-and-length) | |
| 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: ca093103 user: drh tags: faster-typeof-and-length) | |
Changes
Changes to src/vdbe.c.
2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 |
** 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);
sqlite3VdbeSerialGet((u8 *)&zRec[aOffset[p2]], aType[p2], pDest);
}else{
t = aType[p2];
len = sqlite3VdbeSerialTypeLen(t);
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{
sqlite3VdbeMemMove(&sMem, pDest);
rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex,
&sMem);
if( rc!=SQLITE_OK ){
goto op_column_out;
}
zData = sMem.z;
|
> > < > |
2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 |
** 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 ){
/* This is the common case where the whole row fits on a single page */
VdbeMemRelease(pDest);
sqlite3VdbeSerialGet((u8 *)&zRec[aOffset[p2]], aType[p2], pDest);
}else{
/* This branch happens only when the row overflows onto multiple pages */
t = aType[p2];
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;
|