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Overview
| Comment: | Avoid some unnecessary calls to sqlite3VdbeRecordUnpack() that were being made when merging data from two or more temp files together in vdbesort.c |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
707ea170b3e26965b7e3982f7554d122 |
| User & Date: | dan 2014-03-19 20:01:25.712 |
References
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2014-03-29
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| 06:27 | Add the optimization to avoid some unnecessary calls to sqlite3VdbeRecordUnpack() added to the trunk by [707ea170b3]. (check-in: fc4d04e6b0 user: dan tags: threads) | |
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2014-03-25
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| 17:07 | Fix a problem in the code added by [707ea170b3] causing vdbesort.c to sort unstably. (check-in: d3e640afe6 user: dan tags: orderby-planning) | |
Context
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2014-03-20
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| 12:17 | Fix an unnecessarily obtuse use of a bitmask flag. (check-in: ca31408131 user: drh tags: trunk) | |
| 08:59 | Add an experimental fix to avoid attempting to mmap memory from an offset that is not a multiple of the system page size on systems with page sizes larger than 32KB. (check-in: 6f3a5c24d2 user: dan tags: shm-mapping-fix) | |
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2014-03-19
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| 23:42 | Merge the vdbesort.c optimization from trunk. (check-in: e4bfffb988 user: drh tags: orderby-planning) | |
| 20:01 | Avoid some unnecessary calls to sqlite3VdbeRecordUnpack() that were being made when merging data from two or more temp files together in vdbesort.c (check-in: 707ea170b3 user: dan tags: trunk) | |
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2014-03-17
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| 15:06 | Clean up some obsolete "register" declarations in printf.c. (check-in: ecd9d3f945 user: drh tags: trunk) | |
Changes
Changes to src/vdbesort.c.
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*/
int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){
VdbeSorter *pSorter = pCsr->pSorter;
int rc; /* Return code */
if( pSorter->aTree ){
int iPrev = pSorter->aTree[1];/* Index of iterator to advance */
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*/
int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){
VdbeSorter *pSorter = pCsr->pSorter;
int rc; /* Return code */
if( pSorter->aTree ){
int iPrev = pSorter->aTree[1];/* Index of iterator to advance */
rc = vdbeSorterIterNext(db, &pSorter->aIter[iPrev]);
if( rc==SQLITE_OK ){
int i; /* Index of aTree[] to recalculate */
VdbeSorterIter *pIter1; /* First iterator to compare */
VdbeSorterIter *pIter2; /* Second iterator to compare */
u8 *pKey2; /* To pIter2->aKey, or 0 if record cached */
/* Find the first two iterators to compare. The one that was just
** advanced (iPrev) and the one next to it in the array. */
pIter1 = &pSorter->aIter[(iPrev & 0xFFFE)];
pIter2 = &pSorter->aIter[(iPrev | 0x0001)];
pKey2 = pIter2->aKey;
for(i=(pSorter->nTree+iPrev)/2; i>0; i=i/2){
/* Compare pIter1 and pIter2. Store the result in variable iRes. */
int iRes;
if( pIter1->pFile==0 ){
iRes = +1;
}else if( pIter2->pFile==0 ){
iRes = -1;
}else{
vdbeSorterCompare(pCsr, 0,
pIter1->aKey, pIter1->nKey, pKey2, pIter2->nKey, &iRes
);
}
/* If pIter1 contained the smaller value, set aTree[i] to its index.
** Then set pIter2 to the next iterator to compare to pIter1. In this
** case there is no cache of pIter2 in pSorter->pUnpacked, so set
** pKey2 to point to the record belonging to pIter2.
**
** Alternatively, if pIter2 contains the smaller of the two values,
** set aTree[i] to its index and update pIter1. If vdbeSorterCompare()
** was actually called above, then pSorter->pUnpacked now contains
** a value equivalent to pIter2. So set pKey2 to NULL to prevent
** vdbeSorterCompare() from decoding pIter2 again. */
if( iRes<=0 ){
pSorter->aTree[i] = (pIter1 - pSorter->aIter);
pIter2 = &pSorter->aIter[ pSorter->aTree[i ^ 0x0001] ];
pKey2 = pIter2->aKey;
}else{
if( pIter1->pFile ) pKey2 = 0;
pSorter->aTree[i] = (pIter2 - pSorter->aIter);
pIter1 = &pSorter->aIter[ pSorter->aTree[i ^ 0x0001] ];
}
}
*pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0);
}
}else{
SorterRecord *pFree = pSorter->pRecord;
pSorter->pRecord = pFree->pNext;
pFree->pNext = 0;
vdbeSorterRecordFree(db, pFree);
*pbEof = !pSorter->pRecord;
rc = SQLITE_OK;
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