diff options
Diffstat (limited to 'src/backend/executor/execTuples.c')
| -rw-r--r-- | src/backend/executor/execTuples.c | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c index 7a4f11f5d9f..09c7dd55f50 100644 --- a/src/backend/executor/execTuples.c +++ b/src/backend/executor/execTuples.c @@ -15,7 +15,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/execTuples.c,v 1.89 2005/11/22 18:17:10 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/executor/execTuples.c,v 1.90 2005/11/25 04:24:48 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -402,28 +402,38 @@ ExecStoreTuple(HeapTuple tuple, Assert(BufferIsValid(buffer) ? (!shouldFree) : true); /* - * clear out any old contents of the slot + * Free any old physical tuple belonging to the slot. */ - if (!slot->tts_isempty) - ExecClearTuple(slot); + if (slot->tts_shouldFree) + heap_freetuple(slot->tts_tuple); /* - * store the new tuple into the specified slot. + * Store the new tuple into the specified slot. */ slot->tts_isempty = false; slot->tts_shouldFree = shouldFree; slot->tts_tuple = tuple; + /* Mark extracted state invalid */ + slot->tts_nvalid = 0; + /* * If tuple is on a disk page, keep the page pinned as long as we hold a * pointer into it. We assume the caller already has such a pin. + * + * This is coded to optimize the case where the slot previously held a + * tuple on the same disk page: in that case releasing and re-acquiring + * the pin is a waste of cycles. This is a common situation during + * seqscans, so it's worth troubling over. */ - slot->tts_buffer = buffer; - if (BufferIsValid(buffer)) - IncrBufferRefCount(buffer); - - /* Mark extracted state invalid */ - slot->tts_nvalid = 0; + if (slot->tts_buffer != buffer) + { + if (BufferIsValid(slot->tts_buffer)) + ReleaseBuffer(slot->tts_buffer); + slot->tts_buffer = buffer; + if (BufferIsValid(buffer)) + IncrBufferRefCount(buffer); + } return slot; } |