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Add a WHEN clause to CREATE TRIGGER, allowing a boolean expression to be

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checked to determine whether the trigger should be fired.

For BEFORE triggers this is mostly a matter of spec compliance; but for AFTER
triggers it can provide a noticeable performance improvement, since queuing of
a deferred trigger event and re-fetching of the row(s) at end of statement can
be short-circuited if the trigger does not need to be fired.

Takahiro Itagaki, reviewed by KaiGai Kohei.
This commit is contained in:
Tom Lane
2009-11-20 20:38:12 +00:00
parent 201a45c4fa
commit 7fc0f06221
27 changed files with 783 additions and 100 deletions
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6
src/backend/executor/execMain.c
View File

@ -26,7 +26,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.334 2009/10/26 02:26:29 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.335 2009/11/20 20:38:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -752,6 +752,7 @@ InitPlan(QueryDesc *queryDesc, int eflags)
*/
estate->es_tupleTable = NIL;
estate->es_trig_tuple_slot = NULL;
estate->es_trig_oldtup_slot = NULL;
/* mark EvalPlanQual not active */
estate->es_epqTuple = NULL;
@ -911,6 +912,8 @@ InitResultRelInfo(ResultRelInfo *resultRelInfo,
resultRelInfo->ri_TrigFunctions = (FmgrInfo *)
palloc0(n * sizeof(FmgrInfo));
resultRelInfo->ri_TrigWhenExprs = (List **)
palloc0(n * sizeof(List *));
if (doInstrument)
resultRelInfo->ri_TrigInstrument = InstrAlloc(n);
else
@ -919,6 +922,7 @@ InitResultRelInfo(ResultRelInfo *resultRelInfo,
else
{
resultRelInfo->ri_TrigFunctions = NULL;
resultRelInfo->ri_TrigWhenExprs = NULL;
resultRelInfo->ri_TrigInstrument = NULL;
}
resultRelInfo->ri_ConstraintExprs = NULL;

55
src/backend/executor/execQual.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.254 2009/11/04 22:26:05 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.255 2009/11/20 20:38:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -491,26 +491,15 @@ ExecEvalVar(ExprState *exprstate, ExprContext *econtext,
if (isDone)
*isDone = ExprSingleResult;
/*
* Get the input slot and attribute number we want
*
* The asserts check that references to system attributes only appear at
* the level of a relation scan; at higher levels, system attributes must
* be treated as ordinary variables (since we no longer have access to the
* original tuple).
*/
attnum = variable->varattno;
/* Get the input slot and attribute number we want */
switch (variable->varno)
{
case INNER: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
Assert(attnum > 0);
break;
case OUTER: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
Assert(attnum > 0);
break;
default: /* get the tuple from the relation being
@ -519,6 +508,8 @@ ExecEvalVar(ExprState *exprstate, ExprContext *econtext,
break;
}
attnum = variable->varattno;
if (attnum != InvalidAttrNumber)
{
/*
@ -715,7 +706,7 @@ ExecEvalWholeRowVar(ExprState *exprstate, ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone)
{
Var *variable = (Var *) exprstate->expr;
TupleTableSlot *slot = econtext->ecxt_scantuple;
TupleTableSlot *slot;
HeapTuple tuple;
TupleDesc tupleDesc;
HeapTupleHeader dtuple;
@ -724,6 +715,23 @@ ExecEvalWholeRowVar(ExprState *exprstate, ExprContext *econtext,
*isDone = ExprSingleResult;
*isNull = false;
/* Get the input slot we want */
switch (variable->varno)
{
case INNER: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
break;
case OUTER: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
break;
default: /* get the tuple from the relation being
* scanned */
slot = econtext->ecxt_scantuple;
break;
}
tuple = ExecFetchSlotTuple(slot);
tupleDesc = slot->tts_tupleDescriptor;
@ -766,7 +774,7 @@ ExecEvalWholeRowSlow(ExprState *exprstate, ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone)
{
Var *variable = (Var *) exprstate->expr;
TupleTableSlot *slot = econtext->ecxt_scantuple;
TupleTableSlot *slot;
HeapTuple tuple;
TupleDesc var_tupdesc;
HeapTupleHeader dtuple;
@ -775,6 +783,23 @@ ExecEvalWholeRowSlow(ExprState *exprstate, ExprContext *econtext,
*isDone = ExprSingleResult;
*isNull = false;
/* Get the input slot we want */
switch (variable->varno)
{
case INNER: /* get the tuple from the inner node */
slot = econtext->ecxt_innertuple;
break;
case OUTER: /* get the tuple from the outer node */
slot = econtext->ecxt_outertuple;
break;
default: /* get the tuple from the relation being
* scanned */
slot = econtext->ecxt_scantuple;
break;
}
/*
* Currently, the only case handled here is stripping of trailing resjunk
* fields, which we do in a slightly chintzy way by just adjusting the

3
src/backend/executor/execUtils.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.165 2009/10/26 02:26:29 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.166 2009/11/20 20:38:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -117,6 +117,7 @@ CreateExecutorState(void)
estate->es_trig_target_relations = NIL;
estate->es_trig_tuple_slot = NULL;
estate->es_trig_oldtup_slot = NULL;
estate->es_param_list_info = NULL;
estate->es_param_exec_vals = NULL;

12
src/backend/executor/nodeModifyTable.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeModifyTable.c,v 1.2 2009/10/26 02:26:31 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/nodeModifyTable.c,v 1.3 2009/11/20 20:38:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -215,9 +215,10 @@ ExecInsert(TupleTableSlot *slot,
* slot should not try to clear it.
*/
TupleTableSlot *newslot = estate->es_trig_tuple_slot;
TupleDesc tupdesc = RelationGetDescr(resultRelationDesc);
if (newslot->tts_tupleDescriptor != slot->tts_tupleDescriptor)
ExecSetSlotDescriptor(newslot, slot->tts_tupleDescriptor);
if (newslot->tts_tupleDescriptor != tupdesc)
ExecSetSlotDescriptor(newslot, tupdesc);
ExecStoreTuple(newtuple, newslot, InvalidBuffer, false);
slot = newslot;
tuple = newtuple;
@ -467,9 +468,10 @@ ExecUpdate(ItemPointer tupleid,
* slot should not try to clear it.
*/
TupleTableSlot *newslot = estate->es_trig_tuple_slot;
TupleDesc tupdesc = RelationGetDescr(resultRelationDesc);
if (newslot->tts_tupleDescriptor != slot->tts_tupleDescriptor)
ExecSetSlotDescriptor(newslot, slot->tts_tupleDescriptor);
if (newslot->tts_tupleDescriptor != tupdesc)
ExecSetSlotDescriptor(newslot, tupdesc);
ExecStoreTuple(newtuple, newslot, InvalidBuffer, false);
slot = newslot;
tuple = newtuple;