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Overview
| Comment: | When doing the sqlite3BtreeInsert() overwrite optimization, make sure the memcpy() does not extend off the end of the page. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | 684ef4582ed19b2af22dda6fc085c704 |
| User & Date: | drh 2016-12-09 19:42:18 |
Context
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2016-12-10
| ||
| 04:06 | Avoid signed integer overflow when dealing with a LIMIT and OFFSET whose sum exceeds the maximum integer value. check-in: c9bdf7ad user: drh tags: trunk | |
| 00:14 | In balance_nonroot, try to combine dropCell/insertCell combinations for the dividers into a cell overwrites. This results in a very small (0.05%) performance gain which is probably not worth the added complexity. Closed-Leaf check-in: 478627c9 user: drh tags: failed-dropCell-opt | |
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2016-12-09
| ||
| 19:42 | When doing the sqlite3BtreeInsert() overwrite optimization, make sure the memcpy() does not extend off the end of the page. check-in: 684ef458 user: drh tags: trunk | |
| 18:09 | Additional comments and an assert on the sqlite3BtreeInsert() overwrite optimization. check-in: c1f0ae9d user: drh tags: trunk | |
Changes
Changes to src/btree.c.
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if( info.nSize==szNew && info.nLocal==info.nPayload ){
/* Overwrite the old cell with the new if they are the same size.
** We could also try to do this if the old cell is smaller, then add
** the leftover space to the free list. But experiments show that
** doing that is no faster then skipping this optimization and just
** calling dropCell() and insertCell(). */
assert( rc==SQLITE_OK ); /* clearCell never fails when nLocal==nPayload */
memcpy(oldCell, newCell, szNew);
return SQLITE_OK;
}
dropCell(pPage, idx, info.nSize, &rc);
if( rc ) goto end_insert;
}else if( loc<0 && pPage->nCell>0 ){
assert( pPage->leaf );
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> |
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if( info.nSize==szNew && info.nLocal==info.nPayload ){
/* Overwrite the old cell with the new if they are the same size.
** We could also try to do this if the old cell is smaller, then add
** the leftover space to the free list. But experiments show that
** doing that is no faster then skipping this optimization and just
** calling dropCell() and insertCell(). */
assert( rc==SQLITE_OK ); /* clearCell never fails when nLocal==nPayload */
if( oldCell+szNew > pPage->aDataEnd ) return SQLITE_CORRUPT_BKPT;
memcpy(oldCell, newCell, szNew);
return SQLITE_OK;
}
dropCell(pPage, idx, info.nSize, &rc);
if( rc ) goto end_insert;
}else if( loc<0 && pPage->nCell>0 ){
assert( pPage->leaf );
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