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Overview
| Comment: | Change the OP_Last opcode so that it is a no-op if the cursor is already pointing at the end of the b-tree. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
663473850c4274270445b3771911fa77 |
| User & Date: | drh 2016-11-15 04:00:24.244 |
References
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2017-08-01
| ||
| 18:21 | • New ticket [cb91bf4290] Assertion fault following PRAGMA reverse_unordered_selects=ON. (artifact: b9784104c0 user: drh) | |
Context
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2016-11-15
| ||
| 21:17 | Add a needed #include to speedtest1.c. (check-in: 77aeb705c3 user: drh tags: trunk) | |
| 17:37 | Experimental changes toward making snapshots serializable. (check-in: b6a81fa1fc user: drh tags: serializable-snapshot) | |
| 04:00 | Change the OP_Last opcode so that it is a no-op if the cursor is already pointing at the end of the b-tree. (check-in: 663473850c user: drh tags: trunk) | |
| 02:46 | Make the VACUUM command about 9% faster by avoiding unnecessary calls to sqlite3BtreeMovetoUnpacked() while copying rowid tables. (check-in: 5ed0bd3876 user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
| ︙ | ︙ | |||
4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 |
** that is currently pointing to a row in a (non-empty) table.
** This is a verification routine is used only within assert() statements.
*/
int sqlite3BtreeCursorIsValid(BtCursor *pCur){
return pCur && pCur->eState==CURSOR_VALID;
}
#endif /* NDEBUG */
/*
** Return the value of the integer key or "rowid" for a table btree.
** This routine is only valid for a cursor that is pointing into a
** ordinary table btree. If the cursor points to an index btree or
** is invalid, the result of this routine is undefined.
*/
| > > > > | 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291 |
** that is currently pointing to a row in a (non-empty) table.
** This is a verification routine is used only within assert() statements.
*/
int sqlite3BtreeCursorIsValid(BtCursor *pCur){
return pCur && pCur->eState==CURSOR_VALID;
}
#endif /* NDEBUG */
int sqlite3BtreeCursorIsValidNN(BtCursor *pCur){
assert( pCur!=0 );
return pCur->eState==CURSOR_VALID;
}
/*
** Return the value of the integer key or "rowid" for a table btree.
** This routine is only valid for a cursor that is pointing into a
** ordinary table btree. If the cursor points to an index btree or
** is invalid, the result of this routine is undefined.
*/
|
| ︙ | ︙ |
Changes to src/btree.h.
| ︙ | ︙ | |||
306 307 308 309 310 311 312 313 314 315 316 317 318 319 | int sqlite3BtreeCursorHasHint(BtCursor*, unsigned int mask); int sqlite3BtreeIsReadonly(Btree *pBt); int sqlite3HeaderSizeBtree(void); #ifndef NDEBUG int sqlite3BtreeCursorIsValid(BtCursor*); #endif #ifndef SQLITE_OMIT_BTREECOUNT int sqlite3BtreeCount(BtCursor *, i64 *); #endif #ifdef SQLITE_TEST int sqlite3BtreeCursorInfo(BtCursor*, int*, int); | > | 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 | int sqlite3BtreeCursorHasHint(BtCursor*, unsigned int mask); int sqlite3BtreeIsReadonly(Btree *pBt); int sqlite3HeaderSizeBtree(void); #ifndef NDEBUG int sqlite3BtreeCursorIsValid(BtCursor*); #endif int sqlite3BtreeCursorIsValidNN(BtCursor*); #ifndef SQLITE_OMIT_BTREECOUNT int sqlite3BtreeCount(BtCursor *, i64 *); #endif #ifdef SQLITE_TEST int sqlite3BtreeCursorInfo(BtCursor*, int*, int); |
| ︙ | ︙ |
Changes to src/vdbe.c.
| ︙ | ︙ | |||
4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 |
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
**
** 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.
*/
case OP_Last: { /* jump */
VdbeCursor *pC;
BtCursor *pCrsr;
int res;
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
pC = p->apCsr[pOp->p1];
assert( pC!=0 );
assert( pC->eCurType==CURTYPE_BTREE );
pCrsr = pC->uc.pCursor;
res = 0;
assert( pCrsr!=0 );
| > > > > > > > < < < < > > > > > > > > | 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827 4828 4829 4830 4831 4832 4833 4834 4835 4836 4837 4838 4839 4840 4841 4842 4843 4844 4845 |
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
**
** 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;
BtCursor *pCrsr;
int res;
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
pC = p->apCsr[pOp->p1];
assert( pC!=0 );
assert( pC->eCurType==CURTYPE_BTREE );
pCrsr = pC->uc.pCursor;
res = 0;
assert( pCrsr!=0 );
pC->seekResult = pOp->p3;
#ifdef SQLITE_DEBUG
pC->seekOp = OP_Last;
#endif
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;
}
/* Opcode: Sort P1 P2 * * *
**
** This opcode does exactly the same thing as OP_Rewind except that
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| ︙ | ︙ |