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Overview
| Comment: | Small performance improvement in sqltie3WalFindFrame(). |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: | 52013cad0e6ce2d694f25e2984a76d43 |
| User & Date: | drh 2018-02-21 01:05:37 |
Context
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2018-02-21
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| 01:48 | Remove an unreachable branch in the walIndexPage() logic. check-in: 4e61a973 user: drh tags: trunk | |
| 01:05 | Small performance improvement in sqltie3WalFindFrame(). check-in: 52013cad user: drh tags: trunk | |
| 00:48 | Remove an unnecessary memset(). check-in: e7b7f588 user: drh tags: trunk | |
Changes
Changes to src/wal.c.
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** This condition filters out normal hash-table collisions. ** ** (iFrame<=iLast): ** This condition filters out entries that were added to the hash ** table after the current read-transaction had started. */ iMinHash = walFramePage(pWal->minFrame); for(iHash=walFramePage(iLast); iHash>=iMinHash && iRead==0; iHash--){ volatile ht_slot *aHash; /* Pointer to hash table */ volatile u32 *aPgno; /* Pointer to array of page numbers */ u32 iZero; /* Frame number corresponding to aPgno[0] */ int iKey; /* Hash slot index */ int nCollide; /* Number of hash collisions remaining */ int rc; /* Error code */ ................................................................................ assert( iFrame>iRead || CORRUPT_DB ); iRead = iFrame; } if( (nCollide--)==0 ){ return SQLITE_CORRUPT_BKPT; } } } #ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT /* If expensive assert() statements are available, do a linear search ** of the wal-index file content. Make sure the results agree with the ** result obtained using the hash indexes above. */ { |
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** This condition filters out normal hash-table collisions.
**
** (iFrame<=iLast):
** This condition filters out entries that were added to the hash
** table after the current read-transaction had started.
*/
iMinHash = walFramePage(pWal->minFrame);
for(iHash=walFramePage(iLast); iHash>=iMinHash; iHash--){
volatile ht_slot *aHash; /* Pointer to hash table */
volatile u32 *aPgno; /* Pointer to array of page numbers */
u32 iZero; /* Frame number corresponding to aPgno[0] */
int iKey; /* Hash slot index */
int nCollide; /* Number of hash collisions remaining */
int rc; /* Error code */
................................................................................
assert( iFrame>iRead || CORRUPT_DB );
iRead = iFrame;
}
if( (nCollide--)==0 ){
return SQLITE_CORRUPT_BKPT;
}
}
if( iRead ) break;
}
#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
/* If expensive assert() statements are available, do a linear search
** of the wal-index file content. Make sure the results agree with the
** result obtained using the hash indexes above. */
{
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