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Remove small inefficiency in ExecARDeleteTriggers/ExecARUpdateTriggers.

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Whilst poking at nodeModifyTable.c, I chanced to notice that while
its calls to ExecBR*Triggers and ExecIR*Triggers are protected by
tests to see if there are any relevant triggers to fire, its calls
to ExecAR*Triggers are not; the latter functions do the equivalent
tests themselves.  This seems possibly reasonable given the more
complex conditions involved, but what's less reasonable is that
the ExecAR* functions aren't careful to do no work when there is
no work to be done.  ExecARInsertTriggers gets this right, but the
other two will both force creation of a slot that the query may
have no use for.  ExecARUpdateTriggers additionally performed a
usually-useless ExecClearTuple() on that slot.  This is probably
all pretty microscopic in real workloads, but a cycle shaved is a
cycle earned.
This commit is contained in:
Tom Lane
2021-03-30 20:01:27 -04:00
parent 9ee7d533da
commit 65158f497a
1 changed files with 6 additions and 4 deletions
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10
src/backend/commands/trigger.c
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@ -2546,11 +2546,12 @@ ExecARDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
TransitionCaptureState *transition_capture)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
TupleTableSlot *slot = ExecGetTriggerOldSlot(estate, relinfo);
if ((trigdesc && trigdesc->trig_delete_after_row) ||
(transition_capture && transition_capture->tcs_delete_old_table))
{
TupleTableSlot *slot = ExecGetTriggerOldSlot(estate, relinfo);
Assert(HeapTupleIsValid(fdw_trigtuple) ^ ItemPointerIsValid(tupleid));
if (fdw_trigtuple == NULL)
GetTupleForTrigger(estate,
@ -2829,9 +2830,6 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
TransitionCaptureState *transition_capture)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
TupleTableSlot *oldslot = ExecGetTriggerOldSlot(estate, relinfo);
ExecClearTuple(oldslot);
if ((trigdesc && trigdesc->trig_update_after_row) ||
(transition_capture &&
@ -2844,6 +2842,8 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
* separately for DELETE and INSERT to capture transition table rows.
* In such case, either old tuple or new tuple can be NULL.
*/
TupleTableSlot *oldslot = ExecGetTriggerOldSlot(estate, relinfo);
if (fdw_trigtuple == NULL && ItemPointerIsValid(tupleid))
GetTupleForTrigger(estate,
NULL,
@ -2854,6 +2854,8 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
NULL);
else if (fdw_trigtuple != NULL)
ExecForceStoreHeapTuple(fdw_trigtuple, oldslot, false);
else
ExecClearTuple(oldslot);
AfterTriggerSaveEvent(estate, relinfo, TRIGGER_EVENT_UPDATE,
true, oldslot, newslot, recheckIndexes,