From adfa04293b34ac188c94ca81230348282687d3e9 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 23 Jul 2009 21:27:10 +0000
Subject: [PATCH] Save a few cycles in EXPLAIN and related commands by not
bothering to form a physical tuple in do_tup_output(). A virtual tuple is
easier to set up and also easier for most tuple receivers to process. Per my
comment on Robert Haas' recent patch in this code.
---
src/backend/executor/execTuples.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index dffc7379cbe..d92ba062d44 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 1.108 2009/07/22 17:00:20 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/execTuples.c,v 1.109 2009/07/23 21:27:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1215,27 +1215,28 @@ begin_tup_output_tupdesc(DestReceiver *dest, TupleDesc tupdesc)
/*
* write a single tuple
- *
- * XXX This could be made more efficient, since in reality we probably only
- * need a virtual tuple.
*/
void
do_tup_output(TupOutputState *tstate, Datum *values, bool *isnull)
{
- TupleDesc tupdesc = tstate->slot->tts_tupleDescriptor;
- HeapTuple tuple;
+ TupleTableSlot *slot = tstate->slot;
+ int natts = slot->tts_tupleDescriptor->natts;
- /* form a tuple */
- tuple = heap_form_tuple(tupdesc, values, isnull);
+ /* make sure the slot is clear */
+ ExecClearTuple(slot);
- /* put it in a slot */
- ExecStoreTuple(tuple, tstate->slot, InvalidBuffer, true);
+ /* insert data */
+ memcpy(slot->tts_values, values, natts * sizeof(Datum));
+ memcpy(slot->tts_isnull, isnull, natts * sizeof(bool));
+
+ /* mark slot as containing a virtual tuple */
+ ExecStoreVirtualTuple(slot);
/* send the tuple to the receiver */
- (*tstate->dest->receiveSlot) (tstate->slot, tstate->dest);
+ (*tstate->dest->receiveSlot) (slot, tstate->dest);
/* clean up */
- ExecClearTuple(tstate->slot);
+ ExecClearTuple(slot);
}
/*
--
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