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Reduce the CPU load imposed by sqlit3VdbeCursorMoveto() by factoring out

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some of its functions and by avoiding unnecessary calls.

FossilOrigin-Name: c2799aece17d347c64217a0e407bb10e50c184a3
This commit is contained in:
drh
2014-10-13 16:02:20 +00:00
parent 6cf4a7dfa6
commit c22284f4b3
6 changed files with 43 additions and 21 deletions
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28
src/vdbe.c
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@@ -4313,16 +4313,20 @@ case OP_RowData: {
assert( pC->pseudoTableReg==0 );
assert( pC->pCursor!=0 );
pCrsr = pC->pCursor;
assert( sqlite3BtreeCursorIsValid(pCrsr) );
/* The OP_RowKey and OP_RowData opcodes always follow OP_NotExists or
** OP_Rewind/Op_Next with no intervening instructions that might invalidate
** the cursor. Hence the following sqlite3VdbeCursorMoveto() call is always
** a no-op and can never fail. But we leave it in place as a safety.
** the cursor. If this where not the case, on of the following assert()s
** would fail. Should this ever change (because of changes in the code
** generator) then the fix would be to insert a call to
** sqlite3VdbeCursorMoveto().
*/
assert( pC->deferredMoveto==0 );
assert( sqlite3BtreeCursorIsValid(pCrsr) );
#if 0 /* Not required due to the previous to assert() statements */
rc = sqlite3VdbeCursorMoveto(pC);
if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
if( rc!=SQLITE_OK ) goto abort_due_to_error;
#endif
if( pC->isTable==0 ){
assert( !pC->isTable );
@@ -4391,10 +4395,10 @@ case OP_Rowid: { /* out2-prerelease */
#endif /* SQLITE_OMIT_VIRTUALTABLE */
}else{
assert( pC->pCursor!=0 );
rc = sqlite3VdbeCursorMoveto(pC);
rc = sqlite3VdbeCursorRestore(pC);
if( rc ) goto abort_due_to_error;
rc = sqlite3BtreeKeySize(pC->pCursor, &v);
assert( rc==SQLITE_OK ); /* Always so because of CursorMoveto() above */
assert( rc==SQLITE_OK ); /* Always so because of CursorRestore() above */
}
pOut->u.i = v;
break;
@@ -4752,10 +4756,16 @@ case OP_IdxRowid: { /* out2-prerelease */
pCrsr = pC->pCursor;
assert( pCrsr!=0 );
pOut->flags = MEM_Null;
rc = sqlite3VdbeCursorMoveto(pC);
if( NEVER(rc) ) goto abort_due_to_error;
assert( pC->deferredMoveto==0 );
assert( pC->isTable==0 );
assert( pC->deferredMoveto==0 );
/* sqlite3VbeCursorRestore() can only fail if the record has been deleted
** out from under the cursor. That will never happend for an IdxRowid
** opcode, hence the NEVER() arround the check of the return value.
*/
rc = sqlite3VdbeCursorRestore(pC);
if( NEVER(rc!=SQLITE_OK) ) goto abort_due_to_error;
if( !pC->nullRow ){
rowid = 0; /* Not needed. Only used to silence a warning. */
rc = sqlite3VdbeIdxRowid(db, pCrsr, &rowid);