database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-08-08 14:02:16 +03:00
Code Activity

Change the OP_Last opcode so that it is a no-op if the cursor is already

Browse Source 
pointing at the end of the b-tree.

FossilOrigin-Name: 663473850c4274270445b3771911fa773a8c405f
This commit is contained in:
drh
2016-11-15 04:00:24 +00:00
parent c9b9deaee2
commit d6ef5afe3f
5 changed files with 33 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
src/vdbe.c
View File

@@ -4799,6 +4799,13 @@ case OP_NullRow: {
** This opcode leaves the cursor configured to move in reverse order,
** from the end toward the beginning. In other words, the cursor is
** configured to use Prev, not Next.
**
** If P3 is -1, then the cursor is positioned at the end of the btree
** for the purpose of appending a new entry onto the btree. In that
** case P2 must be 0. It is assumed that the cursor is used only for
** appending and so if the cursor is valid, then the cursor must already
** be pointing at the end of the btree and so no changes are made to
** the cursor.
*/
case OP_Last: { /* jump */
VdbeCursor *pC;
@@ -4812,18 +4819,22 @@ case OP_Last: { /* jump */
pCrsr = pC->uc.pCursor;
res = 0;
assert( pCrsr!=0 );
rc = sqlite3BtreeLast(pCrsr, &res);
pC->nullRow = (u8)res;
pC->deferredMoveto = 0;
pC->cacheStatus = CACHE_STALE;
pC->seekResult = pOp->p3;
#ifdef SQLITE_DEBUG
pC->seekOp = OP_Last;
#endif
if( rc ) goto abort_due_to_error;
if( pOp->p2>0 ){
VdbeBranchTaken(res!=0,2);
if( res ) goto jump_to_p2;
if( pOp->p3==0 || !sqlite3BtreeCursorIsValidNN(pCrsr) ){
rc = sqlite3BtreeLast(pCrsr, &res);
pC->nullRow = (u8)res;
pC->deferredMoveto = 0;
pC->cacheStatus = CACHE_STALE;
if( rc ) goto abort_due_to_error;
if( pOp->p2>0 ){
VdbeBranchTaken(res!=0,2);
if( res ) goto jump_to_p2;
}
}else{
assert( pOp->p2==0 );
}
break;
}