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Overview
| Comment: | Simplification and performance tweaks in vdbeSorterMerge(). |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | merge-sort |
| Files: | files | file ages | folders |
| SHA1: |
99e34bdce4ccca15b79159b03b96787e |
| User & Date: | drh 2011-09-03 16:42:38 |
Context
|
2011-09-03
| ||
| 17:07 | Performance improvements to the external merge-sorter. Keep content on an in-memory linked lists rather than an ephemeral table prior to spilling to disk. Use the external merge-sorter to implement ORDER BY and GROUP BY in addition to CREATE INDEX. check-in: 4c43e8b2 user: drh tags: trunk | |
| 16:42 | Simplification and performance tweaks in vdbeSorterMerge(). Closed-Leaf check-in: 99e34bdc user: drh tags: merge-sort | |
| 14:36 | Reduce the number of VdbeRecordUnpack() calls made in vdbesort.c. check-in: 666c2c3c user: dan tags: merge-sort | |
Changes
Changes to src/vdbesort.c.
486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 |
SorterRecord *p1, /* First list to merge */
SorterRecord *p2, /* Second list to merge */
SorterRecord **ppOut /* OUT: Head of merged list */
){
int rc = SQLITE_OK;
SorterRecord *pFinal = 0;
SorterRecord **pp = &pFinal;
int bKey2InSpace = 0; /* True if pCsr->aSpace contains key2 */
while( p1 || p2 ){
if( p1==0 ){
*pp = p2;
p2 = 0;
}else if( p2==0 ){
*pp = p1;
p1 = 0;
}else{
int res;
rc = vdbeSorterCompare(pCsr, 0,
p1->pVal, p1->nVal, (bKey2InSpace ? 0 : p2->pVal), p2->nVal, &res
);
if( rc!=SQLITE_OK ){
vdbeSorterRecordFree(db, p1);
vdbeSorterRecordFree(db, p2);
vdbeSorterRecordFree(db, pFinal);
pFinal = 0;
break;
}
if( res<=0 ){
*pp = p1;
pp = &p1->pNext;
p1 = p1->pNext;
bKey2InSpace = 1;
}else{
*pp = p2;
pp = &p2->pNext;
p2 = p2->pNext;
bKey2InSpace = 0;
}
*pp = 0;
}
}
*ppOut = pFinal;
return rc;
}
/*
** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK
** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error
** occurs.
*/
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486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 |
SorterRecord *p1, /* First list to merge */
SorterRecord *p2, /* Second list to merge */
SorterRecord **ppOut /* OUT: Head of merged list */
){
int rc = SQLITE_OK;
SorterRecord *pFinal = 0;
SorterRecord **pp = &pFinal;
void *pVal2 = p2 ? p2->pVal : 0;
while( p1 && p2 ){
int res;
rc = vdbeSorterCompare(pCsr, 0, p1->pVal, p1->nVal, pVal2, p2->nVal, &res);
if( rc!=SQLITE_OK ){
*pp = 0;
vdbeSorterRecordFree(db, p1);
vdbeSorterRecordFree(db, p2);
vdbeSorterRecordFree(db, pFinal);
*ppOut = 0;
return rc;
}
if( res<=0 ){
*pp = p1;
pp = &p1->pNext;
p1 = p1->pNext;
pVal2 = 0;
}else{
*pp = p2;
pp = &p2->pNext;
p2 = p2->pNext;
if( p2==0 ) break;
pVal2 = p2->pVal;
}
}
*pp = p1 ? p1 : p2;
*ppOut = pFinal;
return SQLITE_OK;
}
/*
** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK
** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error
** occurs.
*/
|