From b339d1fff6c2f14776af29a35c8550b222ca70b2 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 10 Sep 2004 18:40:09 +0000
Subject: [PATCH] Fire non-deferred AFTER triggers immediately upon query
completion, rather than when returning to the idle loop. This makes no
particular difference for interactively-issued queries, but it makes a big
difference for queries issued within functions: trigger execution now occurs
before the calling function is allowed to proceed. This responds to numerous
complaints about nonintuitive behavior of foreign key checking, such as
http://archives.postgresql.org/pgsql-bugs/2004-09/msg00020.php, and appears
to be required by the SQL99 spec. Also take the opportunity to simplify the
data structures used for the pending-trigger list, rename them for more
clarity, and squeeze out a bit of space.
---
doc/src/sgml/ref/set_constraints.sgml | 31 +-
doc/src/sgml/release.sgml | 26 +-
src/backend/access/transam/xact.c | 82 +-
src/backend/commands/copy.c | 12 +-
src/backend/commands/explain.c | 15 +-
src/backend/commands/portalcmds.c | 4 +-
src/backend/commands/trigger.c | 1195 ++++++++++++---------
src/backend/executor/functions.c | 9 +-
src/backend/executor/spi.c | 12 +-
src/backend/tcop/postgres.c | 5 +-
src/backend/tcop/pquery.c | 22 +-
src/backend/tcop/utility.c | 4 +-
src/backend/utils/adt/ri_triggers.c | 4 +-
src/include/commands/trigger.h | 28 +-
src/test/regress/expected/foreign_key.out | 1 +
src/test/regress/expected/plpgsql.out | 71 ++
src/test/regress/sql/plpgsql.sql | 51 +
17 files changed, 954 insertions(+), 618 deletions(-)
diff --git a/doc/src/sgml/ref/set_constraints.sgml b/doc/src/sgml/ref/set_constraints.sgml
index 0c976c93e25..3bcde91f386 100644
--- a/doc/src/sgml/ref/set_constraints.sgml
+++ b/doc/src/sgml/ref/set_constraints.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_constraints.sgml,v 1.11 2004/09/08 20:47:37 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_constraints.sgml,v 1.12 2004/09/10 18:39:53 tgl Exp $ -->
<refentry id="SQL-SET-CONSTRAINTS">
<refmeta>
<refentrytitle id="SQL-SET-CONSTRAINTS-title">SET CONSTRAINTS</refentrytitle>
@@ -34,13 +34,13 @@ SET CONSTRAINTS { ALL | <replaceable class="parameter">name</replaceable> [, ...
<para>
Upon creation, a constraint is given one of three
- characteristics: <literal>INITIALLY DEFERRED</literal>,
- <literal>INITIALLY IMMEDIATE DEFERRABLE</literal>, or
- <literal>INITIALLY IMMEDIATE NOT DEFERRABLE</literal>. The third
- class is not affected by the <command>SET CONSTRAINTS</command>
- command. The first two classes start every transaction in the
- indicated mode, but their behavior can be changed within a transaction
- by <command>SET CONSTRAINTS</command>.
+ characteristics: <literal>DEFERRABLE INITIALLY DEFERRED</literal>,
+ <literal>DEFERRABLE INITIALLY IMMEDIATE</literal>, or
+ <literal>NOT DEFERRABLE</literal>. The third
+ class is always <literal>IMMEDIATE</literal> and is not affected by the
+ <command>SET CONSTRAINTS</command> command. The first two classes start
+ every transaction in the indicated mode, but their behavior can be changed
+ within a transaction by <command>SET CONSTRAINTS</command>.
</para>
<para>
@@ -52,19 +52,22 @@ SET CONSTRAINTS { ALL | <replaceable class="parameter">name</replaceable> [, ...
</para>
<para>
- When you change the mode of a constraint from <literal>DEFERRED</literal>
+ When <command>SET CONSTRAINTS</command> changes the mode of a constraint
+ from <literal>DEFERRED</literal>
to <literal>IMMEDIATE</literal>, the new mode takes effect
retroactively: any outstanding data modifications that would have
been checked at the end of the transaction are instead checked during the
execution of the <command>SET CONSTRAINTS</command> command.
If any such constraint is violated, the <command>SET CONSTRAINTS</command>
- fails (and does not change the constraint mode).
+ fails (and does not change the constraint mode). Thus, <command>SET
+ CONSTRAINTS</command> can be used to force checking of constraints to
+ occur at a specific point in a transaction.
</para>
<para>
Currently, only foreign key constraints are affected by this
setting. Check and unique constraints are always effectively
- initially immediate not deferrable.
+ not deferrable.
</para>
</refsect1>
@@ -76,11 +79,7 @@ SET CONSTRAINTS { ALL | <replaceable class="parameter">name</replaceable> [, ...
current transaction. Thus, if you execute this command outside of a
transaction block
(<command>BEGIN</command>/<command>COMMIT</command> pair), it will
- not appear to have any effect. If you wish to change the behavior
- of a constraint without needing to issue a <command>SET
- CONSTRAINTS</command> command in every transaction, specify
- <literal>INITIALLY DEFERRED</literal> or <literal>INITIALLY
- IMMEDIATE</literal> when you create the constraint.
+ not appear to have any effect.
</para>
</refsect1>
diff --git a/doc/src/sgml/release.sgml b/doc/src/sgml/release.sgml
index b742f675e30..ddf93a04ff9 100644
--- a/doc/src/sgml/release.sgml
+++ b/doc/src/sgml/release.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.294 2004/08/30 00:47:31 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.295 2004/09/10 18:39:54 tgl Exp $
-->
<appendix id="release">
@@ -336,6 +336,16 @@ $PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.294 2004/08/30 00:47:31 tgl Exp
whitespace (which has always been ignored).
</para>
</listitem>
+
+ <listitem>
+ <para>
+ Non-deferred AFTER triggers are now fired immediately after completion
+ of the triggering query, rather than upon finishing the current
+ interactive command. This makes a difference when the triggering query
+ occurred within a function: the trigger is invoked before the function
+ proceeds to its next operation.
+ </para>
+ </listitem>
</itemizedlist>
</para>
</sect2>
@@ -1424,6 +1434,18 @@ $PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.294 2004/08/30 00:47:31 tgl Exp
<title>Server-Side Language Changes</title>
<itemizedlist>
+ <listitem>
+ <para>
+ Non-deferred AFTER triggers are now fired immediately after completion
+ of the triggering query, rather than upon finishing the current
+ interactive command. This makes a difference when the triggering query
+ occurred within a function: the trigger is invoked before the function
+ proceeds to its next operation. For example, if a function inserts
+ a new row into a table, any non-deferred foreign key checks occur
+ before proceeding with the function.
+ </para>
+ </listitem>
+
<listitem>
<para>
Allow function parameters to be declared with names (Dennis Bjorklund)
@@ -1483,7 +1505,7 @@ $PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.294 2004/08/30 00:47:31 tgl Exp
<listitem>
<para>
- New plperl server-side language (Command Prompt, Andrew Dunstan)
+ Major overhaul of plperl server-side language (Command Prompt, Andrew Dunstan)
</para>
</listitem>
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 92c9de0ea75..47c501c393e 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.186 2004/09/06 17:56:04 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.187 2004/09/10 18:39:55 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -138,7 +138,6 @@ static void CleanupSubTransaction(void);
static void StartAbortedSubTransaction(void);
static void PushTransaction(void);
static void PopTransaction(void);
-static void CommitTransactionToLevel(int level);
static char *CleanupAbortedSubTransactions(bool returnName);
static void AtSubAbort_Memory(void);
@@ -1219,7 +1218,7 @@ StartTransaction(void)
*/
AtStart_Inval();
AtStart_Cache();
- DeferredTriggerBeginXact();
+ AfterTriggerBeginXact();
/*
* done with start processing, set current transaction state to "in
@@ -1253,7 +1252,7 @@ CommitTransaction(void)
* committed. He'll invoke all trigger deferred until XACT before we
* really start on committing the transaction.
*/
- DeferredTriggerEndXact();
+ AfterTriggerEndXact();
/*
* Similarly, let ON COMMIT management do its thing before we start to
@@ -1454,7 +1453,7 @@ AbortTransaction(void)
/*
* do abort processing
*/
- DeferredTriggerAbortXact();
+ AfterTriggerAbortXact();
AtAbort_Portals();
AtEOXact_LargeObject(false); /* 'false' means it's abort */
AtAbort_Notify();
@@ -1672,12 +1671,6 @@ CommitTransactionCommand(void)
* default state.
*/
case TBLOCK_END:
- /* commit all open subtransactions */
- if (s->nestingLevel > 1)
- CommitTransactionToLevel(2);
- s = CurrentTransactionState;
- Assert(s->parent == NULL);
- /* and now the outer transaction */
CommitTransaction();
s->blockState = TBLOCK_DEFAULT;
break;
@@ -1732,11 +1725,10 @@ CommitTransactionCommand(void)
break;
/*
- * We were issued a RELEASE command, so we end the current
- * subtransaction and return to the parent transaction.
- *
- * Since RELEASE can exit multiple levels of subtransaction, we
- * must loop here until we get out of all SUBEND'ed levels.
+ * We were issued a COMMIT or RELEASE command, so we end the
+ * current subtransaction and return to the parent transaction.
+ * Lather, rinse, and repeat until we get out of all SUBEND'ed
+ * subtransaction levels.
*/
case TBLOCK_SUBEND:
do
@@ -1745,6 +1737,13 @@ CommitTransactionCommand(void)
PopTransaction();
s = CurrentTransactionState; /* changed by pop */
} while (s->blockState == TBLOCK_SUBEND);
+ /* If we had a COMMIT command, finish off the main xact too */
+ if (s->blockState == TBLOCK_END)
+ {
+ Assert(s->parent == NULL);
+ CommitTransaction();
+ s->blockState = TBLOCK_DEFAULT;
+ }
break;
/*
@@ -2238,7 +2237,6 @@ EndTransactionBlock(void)
* the default state.
*/
case TBLOCK_INPROGRESS:
- case TBLOCK_SUBINPROGRESS:
s->blockState = TBLOCK_END;
result = true;
break;
@@ -2254,6 +2252,22 @@ EndTransactionBlock(void)
s->blockState = TBLOCK_ENDABORT;
break;
+ /*
+ * We are in a live subtransaction block. Set up to subcommit
+ * all open subtransactions and then commit the main transaction.
+ */
+ case TBLOCK_SUBINPROGRESS:
+ while (s->parent != NULL)
+ {
+ Assert(s->blockState == TBLOCK_SUBINPROGRESS);
+ s->blockState = TBLOCK_SUBEND;
+ s = s->parent;
+ }
+ Assert(s->blockState == TBLOCK_INPROGRESS);
+ s->blockState = TBLOCK_END;
+ result = true;
+ break;
+
/*
* Here we are inside an aborted subtransaction. Go to the
* "abort the whole tree" state so that
@@ -2699,8 +2713,12 @@ ReleaseCurrentSubTransaction(void)
if (s->blockState != TBLOCK_SUBINPROGRESS)
elog(ERROR, "ReleaseCurrentSubTransaction: unexpected state %s",
BlockStateAsString(s->blockState));
+ Assert(s->state == TRANS_INPROGRESS);
MemoryContextSwitchTo(CurTransactionContext);
- CommitTransactionToLevel(GetCurrentTransactionNestLevel());
+ CommitSubTransaction();
+ PopTransaction();
+ s = CurrentTransactionState; /* changed by pop */
+ Assert(s->state == TRANS_INPROGRESS);
}
/*
@@ -2827,28 +2845,6 @@ AbortOutOfAnyTransaction(void)
Assert(s->parent == NULL);
}
-/*
- * CommitTransactionToLevel
- *
- * Commit everything from the current transaction level
- * up to the specified level (inclusive).
- */
-static void
-CommitTransactionToLevel(int level)
-{
- TransactionState s = CurrentTransactionState;
-
- Assert(s->state == TRANS_INPROGRESS);
-
- while (s->nestingLevel >= level)
- {
- CommitSubTransaction();
- PopTransaction();
- s = CurrentTransactionState; /* changed by pop */
- Assert(s->state == TRANS_INPROGRESS);
- }
-}
-
/*
* IsTransactionBlock --- are we within a transaction block?
*/
@@ -2975,7 +2971,7 @@ StartSubTransaction(void)
*/
AtSubStart_Inval();
AtSubStart_Notify();
- DeferredTriggerBeginSubXact();
+ AfterTriggerBeginSubXact();
s->state = TRANS_INPROGRESS;
@@ -3011,7 +3007,7 @@ CommitSubTransaction(void)
AtSubCommit_childXids();
/* Post-commit cleanup */
- DeferredTriggerEndSubXact(true);
+ AfterTriggerEndSubXact(true);
AtSubCommit_Portals(s->parent->transactionIdData,
s->parent->curTransactionOwner);
AtEOSubXact_LargeObject(true, s->transactionIdData,
@@ -3101,7 +3097,7 @@ AbortSubTransaction(void)
*/
AtSubAbort_Memory();
- DeferredTriggerEndSubXact(false);
+ AfterTriggerEndSubXact(false);
AtSubAbort_Portals(s->parent->transactionIdData,
s->parent->curTransactionOwner);
AtEOSubXact_LargeObject(false, s->transactionIdData,
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 5793c0b2bbb..b25c8eee98c 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.230 2004/08/29 05:06:41 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.231 2004/09/10 18:39:56 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1610,6 +1610,11 @@ CopyFrom(Relation rel, List *attnumlist, bool binary, bool oids,
}
}
+ /*
+ * Prepare to catch AFTER triggers.
+ */
+ AfterTriggerBeginQuery();
+
/*
* Check BEFORE STATEMENT insertion triggers. It's debateable whether
* we should do this for COPY, since it's not really an "INSERT"
@@ -1974,6 +1979,11 @@ CopyFrom(Relation rel, List *attnumlist, bool binary, bool oids,
*/
ExecASInsertTriggers(estate, resultRelInfo);
+ /*
+ * Handle queued AFTER triggers
+ */
+ AfterTriggerEndQuery();
+
pfree(values);
pfree(nulls);
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 7ad3596fac6..9b7cf1ae491 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.124 2004/08/29 05:06:41 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.125 2004/09/10 18:39:56 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -18,6 +18,7 @@
#include "catalog/pg_type.h"
#include "commands/explain.h"
#include "commands/prepare.h"
+#include "commands/trigger.h"
#include "executor/executor.h"
#include "executor/instrument.h"
#include "lib/stringinfo.h"
@@ -206,6 +207,10 @@ ExplainOnePlan(QueryDesc *queryDesc, ExplainStmt *stmt,
gettimeofday(&starttime, NULL);
+ /* If analyzing, we need to cope with queued triggers */
+ if (stmt->analyze)
+ AfterTriggerBeginQuery();
+
/* call ExecutorStart to prepare the plan for execution */
ExecutorStart(queryDesc, false, !stmt->analyze);
@@ -255,12 +260,16 @@ ExplainOnePlan(QueryDesc *queryDesc, ExplainStmt *stmt,
}
/*
- * Close down the query and free resources. Include time for this in
- * the total runtime.
+ * Close down the query and free resources; also run any queued
+ * AFTER triggers. Include time for this in the total runtime.
*/
gettimeofday(&starttime, NULL);
ExecutorEnd(queryDesc);
+
+ if (stmt->analyze)
+ AfterTriggerEndQuery();
+
FreeQueryDesc(queryDesc);
CommandCounterIncrement();
diff --git a/src/backend/commands/portalcmds.c b/src/backend/commands/portalcmds.c
index 08b14013547..390e20aa2e9 100644
--- a/src/backend/commands/portalcmds.c
+++ b/src/backend/commands/portalcmds.c
@@ -14,7 +14,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.33 2004/08/29 05:06:41 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.34 2004/09/10 18:39:56 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -273,6 +273,7 @@ PortalCleanup(Portal portal)
{
CurrentResourceOwner = portal->resowner;
ExecutorEnd(queryDesc);
+ /* we do not need AfterTriggerEndQuery() here */
}
PG_CATCH();
{
@@ -373,6 +374,7 @@ PersistHoldablePortal(Portal portal)
*/
portal->queryDesc = NULL; /* prevent double shutdown */
ExecutorEnd(queryDesc);
+ /* we do not need AfterTriggerEndQuery() here */
/*
* Reset the position in the result set: ideally, this could be
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 0efc4afb58c..5480fce189f 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.171 2004/09/08 23:47:58 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.172 2004/09/10 18:39:56 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -48,7 +48,7 @@ static HeapTuple GetTupleForTrigger(EState *estate,
static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
FmgrInfo *finfo,
MemoryContext per_tuple_context);
-static void DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event,
+static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
bool row_trigger, HeapTuple oldtup, HeapTuple newtup);
@@ -1219,8 +1219,8 @@ ExecASInsertTriggers(EState *estate, ResultRelInfo *relinfo)
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_INSERT] > 0)
- DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
- false, NULL, NULL);
+ AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
+ false, NULL, NULL);
}
HeapTuple
@@ -1272,8 +1272,8 @@ ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc && trigdesc->n_after_row[TRIGGER_EVENT_INSERT] > 0)
- DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
- true, NULL, trigtuple);
+ AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
+ true, NULL, trigtuple);
}
void
@@ -1332,8 +1332,8 @@ ExecASDeleteTriggers(EState *estate, ResultRelInfo *relinfo)
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_DELETE] > 0)
- DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
- false, NULL, NULL);
+ AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
+ false, NULL, NULL);
}
bool
@@ -1399,8 +1399,8 @@ ExecARDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
(CommandId) 0,
NULL);
- DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
- true, trigtuple, NULL);
+ AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
+ true, trigtuple, NULL);
heap_freetuple(trigtuple);
}
}
@@ -1461,8 +1461,8 @@ ExecASUpdateTriggers(EState *estate, ResultRelInfo *relinfo)
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_UPDATE] > 0)
- DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
- false, NULL, NULL);
+ AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
+ false, NULL, NULL);
}
HeapTuple
@@ -1535,8 +1535,8 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
(CommandId) 0,
NULL);
- DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
- true, trigtuple, newtuple);
+ AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
+ true, trigtuple, newtuple);
heap_freetuple(trigtuple);
}
}
@@ -1635,87 +1635,35 @@ ltrmark:;
/* ----------
- * Deferred trigger stuff
+ * After-trigger stuff
*
- * The DeferredTriggersData struct holds data about pending deferred
- * trigger events during the current transaction tree. The struct and
- * most of its subsidiary data are kept in TopTransactionContext; however
+ * The AfterTriggersData struct holds data about pending AFTER trigger events
+ * during the current transaction tree. (BEFORE triggers are fired
+ * immediately so we don't need any persistent state about them.) The struct
+ * and most of its subsidiary data are kept in TopTransactionContext; however
* the individual event records are kept in CurTransactionContext, so that
* they will easily go away during subtransaction abort.
*
- * DeferredTriggersData has the following fields:
- *
- * state keeps track of the deferred state of each trigger
- * (including the global state). This is saved and restored across
- * failed subtransactions.
- *
- * events is the head of the list of events.
- *
- * tail_thisxact points to the tail of the list, for the current
- * transaction (whether main transaction or subtransaction). We always
- * append to the list using this pointer.
- *
- * events_imm points to the last element scanned by the last
- * deferredTriggerInvokeEvents call. We can use this to avoid rescanning
- * unnecessarily; if it's NULL, the scan should start at the head of the
- * list. Its name comes from the fact that it's set to the last event fired
- * by the last call to immediate triggers.
- *
- * tail_stack and imm_stack are stacks of pointer, which hold the pointers
- * to the tail and the "immediate" events as of the start of a subtransaction.
- * We use to revert them when aborting the subtransaction.
- *
- * state_stack is a stack of pointers to saved copies of the deferred-trigger
- * state data; each subtransaction level that modifies that state first
- * saves a copy, which we use to restore the state if we abort.
- *
- * We use GetCurrentTransactionNestLevel() to determine the correct array
- * index in these stacks. numalloc is the number of allocated entries in
- * each stack. (By not keeping our own stack pointer, we can avoid trouble
- * in cases where errors during subxact abort cause multiple invocations
- * of DeferredTriggerEndSubXact() at the same nesting depth.)
+ * Because the list of pending events can grow large, we go to some effort
+ * to minimize memory consumption. We do not use the generic List mechanism
+ * but thread the events manually.
*
* XXX We need to be able to save the per-event data in a file if it grows too
* large.
* ----------
*/
-/* Per-item data */
-typedef struct DeferredTriggerEventItem
-{
- Oid dti_tgoid;
- TransactionId dti_done_xid;
- int32 dti_state;
-} DeferredTriggerEventItem;
-
-typedef struct DeferredTriggerEventData *DeferredTriggerEvent;
-
-/* Per-event data */
-typedef struct DeferredTriggerEventData
-{
- DeferredTriggerEvent dte_next; /* list link */
- int32 dte_event;
- Oid dte_relid;
- TransactionId dte_done_xid;
- ItemPointerData dte_oldctid;
- ItemPointerData dte_newctid;
- int32 dte_n_items;
- /* dte_item is actually a variable-size array, of length dte_n_items */
- DeferredTriggerEventItem dte_item[1];
-} DeferredTriggerEventData;
-
-/* Per-trigger status data */
-typedef struct DeferredTriggerStatusData
+/* Per-trigger SET CONSTRAINT status */
+typedef struct SetConstraintTriggerData
{
- Oid dts_tgoid;
- bool dts_tgisdeferred;
-} DeferredTriggerStatusData;
-
-typedef struct DeferredTriggerStatusData *DeferredTriggerStatus;
+ Oid sct_tgoid;
+ bool sct_tgisdeferred;
+} SetConstraintTriggerData;
+typedef struct SetConstraintTriggerData *SetConstraintTrigger;
/*
- * Trigger deferral status data.
+ * SET CONSTRAINT intra-transaction status.
*
* We make this a single palloc'd object so it can be copied and freed easily.
*
@@ -1724,62 +1672,148 @@ typedef struct DeferredTriggerStatusData *DeferredTriggerStatus;
*
* trigstates[] stores per-trigger tgisdeferred settings.
*/
-typedef struct DeferredTriggerStateData
+typedef struct SetConstraintStateData
{
bool all_isset;
bool all_isdeferred;
int numstates; /* number of trigstates[] entries in use */
int numalloc; /* allocated size of trigstates[] */
- DeferredTriggerStatusData trigstates[1]; /* VARIABLE LENGTH ARRAY */
-} DeferredTriggerStateData;
+ SetConstraintTriggerData trigstates[1]; /* VARIABLE LENGTH ARRAY */
+} SetConstraintStateData;
-typedef DeferredTriggerStateData *DeferredTriggerState;
+typedef SetConstraintStateData *SetConstraintState;
-/* Per-transaction data */
-typedef struct DeferredTriggersData
-{
- DeferredTriggerState state;
- DeferredTriggerEvent events;
- DeferredTriggerEvent tail_thisxact;
- DeferredTriggerEvent events_imm;
- DeferredTriggerEvent *tail_stack;
- DeferredTriggerEvent *imm_stack;
- DeferredTriggerState *state_stack;
- int numalloc;
-} DeferredTriggersData;
-typedef DeferredTriggersData *DeferredTriggers;
+/*
+ * Per-trigger-event data
+ *
+ * Note: ate_firing_id is meaningful when either AFTER_TRIGGER_DONE
+ * or AFTER_TRIGGER_IN_PROGRESS is set. It indicates which trigger firing
+ * cycle the trigger was or will be fired in.
+ */
+typedef struct AfterTriggerEventData *AfterTriggerEvent;
-static DeferredTriggers deferredTriggers;
+typedef struct AfterTriggerEventData
+{
+ AfterTriggerEvent ate_next; /* list link */
+ TriggerEvent ate_event; /* event type and status bits */
+ CommandId ate_firing_id; /* ID for firing cycle */
+ Oid ate_tgoid; /* the trigger's ID */
+ Oid ate_relid; /* the relation it's on */
+ ItemPointerData ate_oldctid; /* specific tuple(s) involved */
+ ItemPointerData ate_newctid;
+} AfterTriggerEventData;
+
+/* A list of events */
+typedef struct AfterTriggerEventList
+{
+ AfterTriggerEvent head;
+ AfterTriggerEvent tail;
+} AfterTriggerEventList;
-static void DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
- Relation rel, TriggerDesc *trigdesc, FmgrInfo *finfo,
- MemoryContext per_tuple_context);
-static DeferredTriggerState DeferredTriggerStateCreate(int numalloc);
-static DeferredTriggerState DeferredTriggerStateCopy(DeferredTriggerState state);
-static DeferredTriggerState DeferredTriggerStateAddItem(DeferredTriggerState state,
+/*
+ * All per-transaction data for the AFTER TRIGGERS module.
+ *
+ * AfterTriggersData has the following fields:
+ *
+ * firing_counter is incremented for each call of afterTriggerInvokeEvents.
+ * We mark firable events with the current firing cycle's ID so that we can
+ * tell which ones to work on. This ensures sane behavior if a trigger
+ * function chooses to do SET CONSTRAINTS: the inner SET CONSTRAINTS will
+ * only fire those events that weren't already scheduled for firing.
+ *
+ * state keeps track of the transaction-local effects of SET CONSTRAINTS.
+ * This is saved and restored across failed subtransactions.
+ *
+ * events is the current list of deferred events. This is global across
+ * all subtransactions of the current transaction. In a subtransaction
+ * abort, we know that the events added by the subtransaction are at the
+ * end of the list, so it is relatively easy to discard them.
+ *
+ * query_depth is the current depth of nested AfterTriggerBeginQuery calls
+ * (-1 when the stack is empty).
+ *
+ * query_stack[query_depth] is a list of AFTER trigger events queued by the
+ * current query (and the query_stack entries below it are lists of trigger
+ * events queued by calling queries). None of these are valid until the
+ * matching AfterTriggerEndQuery call occurs. At that point we fire
+ * immediate-mode triggers, and append any deferred events to the main events
+ * list.
+ *
+ * maxquerydepth is just the allocated length of query_stack.
+ *
+ * state_stack is a stack of pointers to saved copies of the SET CONSTRAINTS
+ * state data; each subtransaction level that modifies that state first
+ * saves a copy, which we use to restore the state if we abort.
+ *
+ * events_stack is a stack of copies of the events head/tail pointers,
+ * which we use to restore those values during subtransaction abort.
+ *
+ * depth_stack is a stack of copies of subtransaction-start-time query_depth,
+ * which we similarly use to clean up at subtransaction abort.
+ *
+ * firing_stack is a stack of copies of subtransaction-start-time
+ * firing_counter. We use this to recognize which deferred triggers were
+ * fired (or marked for firing) within an aborted subtransaction.
+ *
+ * We use GetCurrentTransactionNestLevel() to determine the correct array
+ * index in these stacks. maxtransdepth is the number of allocated entries in
+ * each stack. (By not keeping our own stack pointer, we can avoid trouble
+ * in cases where errors during subxact abort cause multiple invocations
+ * of AfterTriggerEndSubXact() at the same nesting depth.)
+ */
+typedef struct AfterTriggersData
+{
+ CommandId firing_counter; /* next firing ID to assign */
+ SetConstraintState state; /* the active S C state */
+ AfterTriggerEventList events; /* deferred-event list */
+ int query_depth; /* current query list index */
+ AfterTriggerEventList *query_stack; /* events pending from each query */
+ int maxquerydepth; /* allocated len of above array */
+
+ /* these fields are just for resetting at subtrans abort: */
+
+ SetConstraintState *state_stack; /* stacked S C states */
+ AfterTriggerEventList *events_stack; /* stacked list pointers */
+ int *depth_stack; /* stacked query_depths */
+ CommandId *firing_stack; /* stacked firing_counters */
+ int maxtransdepth; /* allocated len of above arrays */
+} AfterTriggersData;
+
+typedef AfterTriggersData *AfterTriggers;
+
+static AfterTriggers afterTriggers;
+
+
+static void AfterTriggerExecute(AfterTriggerEvent event,
+ Relation rel, TriggerDesc *trigdesc,
+ FmgrInfo *finfo,
+ MemoryContext per_tuple_context);
+static SetConstraintState SetConstraintStateCreate(int numalloc);
+static SetConstraintState SetConstraintStateCopy(SetConstraintState state);
+static SetConstraintState SetConstraintStateAddItem(SetConstraintState state,
Oid tgoid, bool tgisdeferred);
/* ----------
- * deferredTriggerCheckState()
+ * afterTriggerCheckState()
*
* Returns true if the trigger identified by tgoid is actually
* in state DEFERRED.
* ----------
*/
static bool
-deferredTriggerCheckState(Oid tgoid, int32 itemstate)
+afterTriggerCheckState(Oid tgoid, TriggerEvent eventstate)
{
- DeferredTriggerState state = deferredTriggers->state;
+ SetConstraintState state = afterTriggers->state;
int i;
/*
* For not-deferrable triggers (i.e. normal AFTER ROW triggers and
* constraints declared NOT DEFERRABLE), the state is always false.
*/
- if ((itemstate & TRIGGER_DEFERRED_DEFERRABLE) == 0)
+ if ((eventstate & AFTER_TRIGGER_DEFERRABLE) == 0)
return false;
/*
@@ -1787,8 +1821,8 @@ deferredTriggerCheckState(Oid tgoid, int32 itemstate)
*/
for (i = 0; i < state->numstates; i++)
{
- if (state->trigstates[i].dts_tgoid == tgoid)
- return state->trigstates[i].dts_tgisdeferred;
+ if (state->trigstates[i].sct_tgoid == tgoid)
+ return state->trigstates[i].sct_tgisdeferred;
}
/*
@@ -1800,37 +1834,43 @@ deferredTriggerCheckState(Oid tgoid, int32 itemstate)
/*
* Otherwise return the default state for the trigger.
*/
- return ((itemstate & TRIGGER_DEFERRED_INITDEFERRED) != 0);
+ return ((eventstate & AFTER_TRIGGER_INITDEFERRED) != 0);
}
/* ----------
- * deferredTriggerAddEvent()
+ * afterTriggerAddEvent()
*
- * Add a new trigger event to the queue.
+ * Add a new trigger event to the current query's queue.
* ----------
*/
static void
-deferredTriggerAddEvent(DeferredTriggerEvent event)
+afterTriggerAddEvent(AfterTriggerEvent event)
{
- Assert(event->dte_next == NULL);
+ AfterTriggerEventList *events;
+
+ Assert(event->ate_next == NULL);
- if (deferredTriggers->tail_thisxact == NULL)
+ /* Must be inside a query */
+ Assert(afterTriggers->query_depth >= 0);
+
+ events = &afterTriggers->query_stack[afterTriggers->query_depth];
+ if (events->tail == NULL)
{
/* first list entry */
- deferredTriggers->events = event;
- deferredTriggers->tail_thisxact = event;
+ events->head = event;
+ events->tail = event;
}
else
{
- deferredTriggers->tail_thisxact->dte_next = event;
- deferredTriggers->tail_thisxact = event;
+ events->tail->ate_next = event;
+ events->tail = event;
}
}
/* ----------
- * DeferredTriggerExecute()
+ * AfterTriggerExecute()
*
* Fetch the required tuples back from the heap and fire one
* single trigger function.
@@ -1840,7 +1880,6 @@ deferredTriggerAddEvent(DeferredTriggerEvent event)
* fmgr lookup cache space at the caller level.
*
* event: event currently being fired.
- * itemno: item within event currently being fired.
* rel: open relation for event.
* trigdesc: working copy of rel's trigger info.
* finfo: array of fmgr lookup cache entries (one per trigger in trigdesc).
@@ -1848,11 +1887,11 @@ deferredTriggerAddEvent(DeferredTriggerEvent event)
* ----------
*/
static void
-DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
+AfterTriggerExecute(AfterTriggerEvent event,
Relation rel, TriggerDesc *trigdesc, FmgrInfo *finfo,
- MemoryContext per_tuple_context)
+ MemoryContext per_tuple_context)
{
- Oid tgoid = event->dte_item[itemno].dti_tgoid;
+ Oid tgoid = event->ate_tgoid;
TriggerData LocTriggerData;
HeapTupleData oldtuple;
HeapTupleData newtuple;
@@ -1864,26 +1903,26 @@ DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
/*
* Fetch the required OLD and NEW tuples.
*/
- if (ItemPointerIsValid(&(event->dte_oldctid)))
+ if (ItemPointerIsValid(&(event->ate_oldctid)))
{
- ItemPointerCopy(&(event->dte_oldctid), &(oldtuple.t_self));
+ ItemPointerCopy(&(event->ate_oldctid), &(oldtuple.t_self));
if (!heap_fetch(rel, SnapshotAny, &oldtuple, &oldbuffer, false, NULL))
- elog(ERROR, "failed to fetch old tuple for deferred trigger");
+ elog(ERROR, "failed to fetch old tuple for AFTER trigger");
}
- if (ItemPointerIsValid(&(event->dte_newctid)))
+ if (ItemPointerIsValid(&(event->ate_newctid)))
{
- ItemPointerCopy(&(event->dte_newctid), &(newtuple.t_self));
+ ItemPointerCopy(&(event->ate_newctid), &(newtuple.t_self));
if (!heap_fetch(rel, SnapshotAny, &newtuple, &newbuffer, false, NULL))
- elog(ERROR, "failed to fetch new tuple for deferred trigger");
+ elog(ERROR, "failed to fetch new tuple for AFTER trigger");
}
/*
* Setup the trigger information
*/
LocTriggerData.type = T_TriggerData;
- LocTriggerData.tg_event = (event->dte_event & TRIGGER_EVENT_OPMASK) |
- (event->dte_event & TRIGGER_EVENT_ROW);
+ LocTriggerData.tg_event =
+ event->ate_event & (TRIGGER_EVENT_OPMASK | TRIGGER_EVENT_ROW);
LocTriggerData.tg_relation = rel;
LocTriggerData.tg_trigger = NULL;
@@ -1898,7 +1937,7 @@ DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
if (LocTriggerData.tg_trigger == NULL)
elog(ERROR, "could not find trigger %u", tgoid);
- switch (event->dte_event & TRIGGER_EVENT_OPMASK)
+ switch (event->ate_event & TRIGGER_EVENT_OPMASK)
{
case TRIGGER_EVENT_INSERT:
LocTriggerData.tg_trigtuple = &newtuple;
@@ -1916,6 +1955,8 @@ DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
break;
}
+ MemoryContextReset(per_tuple_context);
+
/*
* Call the trigger and throw away any eventually returned updated
* tuple.
@@ -1929,290 +1970,409 @@ DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
/*
* Release buffers
*/
- if (ItemPointerIsValid(&(event->dte_oldctid)))
+ if (ItemPointerIsValid(&(event->ate_oldctid)))
ReleaseBuffer(oldbuffer);
- if (ItemPointerIsValid(&(event->dte_newctid)))
+ if (ItemPointerIsValid(&(event->ate_newctid)))
ReleaseBuffer(newbuffer);
}
+/*
+ * afterTriggerMarkEvents()
+ *
+ * Scan the given event list for not yet invoked events. Mark the ones
+ * that can be invoked now with the current firing ID.
+ *
+ * If move_list isn't NULL, events that are not to be invoked now are
+ * removed from the given list and appended to move_list.
+ *
+ * When immediate_only is TRUE, do not invoke currently-deferred triggers.
+ * (This will be FALSE only at main transaction exit.)
+ *
+ * Returns TRUE if any invokable events were found.
+ */
+static bool
+afterTriggerMarkEvents(AfterTriggerEventList *events,
+ AfterTriggerEventList *move_list,
+ bool immediate_only)
+{
+ bool found = false;
+ AfterTriggerEvent event,
+ prev_event;
+
+ prev_event = NULL;
+ event = events->head;
+
+ while (event != NULL)
+ {
+ bool defer_it = false;
+ AfterTriggerEvent next_event;
+
+ if (!(event->ate_event &
+ (AFTER_TRIGGER_DONE | AFTER_TRIGGER_IN_PROGRESS)))
+ {
+ /*
+ * This trigger hasn't been called or scheduled yet. Check if we
+ * should call it now.
+ */
+ if (immediate_only &&
+ afterTriggerCheckState(event->ate_tgoid, event->ate_event))
+ {
+ defer_it = true;
+ }
+ else
+ {
+ /*
+ * Mark it as to be fired in this firing cycle.
+ */
+ event->ate_firing_id = afterTriggers->firing_counter;
+ event->ate_event |= AFTER_TRIGGER_IN_PROGRESS;
+ found = true;
+ }
+ }
+
+ /*
+ * If it's deferred, move it to move_list, if requested.
+ */
+ next_event = event->ate_next;
+
+ if (defer_it && move_list != NULL)
+ {
+ /* Delink it from input list */
+ if (prev_event)
+ prev_event->ate_next = next_event;
+ else
+ events->head = next_event;
+ /* and add it to move_list */
+ event->ate_next = NULL;
+ if (move_list->tail == NULL)
+ {
+ /* first list entry */
+ move_list->head = event;
+ move_list->tail = event;
+ }
+ else
+ {
+ move_list->tail->ate_next = event;
+ move_list->tail = event;
+ }
+ }
+ else
+ {
+ /* Keep it in input list */
+ prev_event = event;
+ }
+
+ event = next_event;
+ }
+
+ /* Update list tail pointer in case we moved tail event */
+ events->tail = prev_event;
+
+ return found;
+}
+
/* ----------
- * deferredTriggerInvokeEvents()
+ * afterTriggerInvokeEvents()
*
- * Scan the event queue for not yet invoked triggers. Check if they
- * should be invoked now and do so.
+ * Scan the given event list for events that are marked as to be fired
+ * in the current firing cycle, and fire them.
+ *
+ * When delete_ok is TRUE, it's okay to delete fully-processed events.
+ * The events list pointers are updated.
* ----------
*/
static void
-deferredTriggerInvokeEvents(bool immediate_only)
+afterTriggerInvokeEvents(AfterTriggerEventList *events,
+ CommandId firing_id,
+ bool delete_ok)
{
- DeferredTriggerEvent event,
+ AfterTriggerEvent event,
prev_event;
MemoryContext per_tuple_context;
Relation rel = NULL;
TriggerDesc *trigdesc = NULL;
FmgrInfo *finfo = NULL;
- /*
- * If immediate_only is true, we remove fully-processed events from
- * the event queue to recycle space. If immediate_only is false, we
- * are going to discard the whole event queue on return anyway, so no
- * need to bother with "retail" pfree's.
- *
- * If immediate_only is true, we need only scan from where the end of the
- * queue was at the previous deferredTriggerInvokeEvents call; any
- * non-deferred events before that point are already fired. (But if
- * the deferral state changes, we must reset the saved position to the
- * beginning of the queue, so as to process all events once with the
- * new states. See DeferredTriggerSetState.)
- */
-
/* Make a per-tuple memory context for trigger function calls */
per_tuple_context =
AllocSetContextCreate(CurrentMemoryContext,
- "DeferredTriggerTupleContext",
+ "AfterTriggerTupleContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
- /*
- * If immediate_only is true, then the only events that could need
- * firing are those since events_imm. (But if events_imm is NULL, we
- * must scan the entire list.)
- */
- if (immediate_only && deferredTriggers->events_imm != NULL)
- {
- prev_event = deferredTriggers->events_imm;
- event = prev_event->dte_next;
- }
- else
- {
- prev_event = NULL;
- event = deferredTriggers->events;
- }
+ prev_event = NULL;
+ event = events->head;
while (event != NULL)
{
- bool still_deferred_ones = false;
- DeferredTriggerEvent next_event;
- int i;
+ AfterTriggerEvent next_event;
/*
- * Skip executing cancelled events, and events already done,
- * unless they were done by a subtransaction that later aborted.
+ * Is it one for me to fire?
*/
- if (!(event->dte_event & TRIGGER_DEFERRED_CANCELED) &&
- !(event->dte_event & TRIGGER_DEFERRED_DONE &&
- TransactionIdIsValid(event->dte_done_xid) &&
- !TransactionIdDidAbort(event->dte_done_xid)))
+ if ((event->ate_event & AFTER_TRIGGER_IN_PROGRESS) &&
+ event->ate_firing_id == firing_id)
{
- MemoryContextReset(per_tuple_context);
-
/*
- * Check each trigger item in the event.
+ * So let's fire it... but first, open the correct
+ * relation if this is not the same relation as before.
*/
- for (i = 0; i < event->dte_n_items; i++)
+ if (rel == NULL || rel->rd_id != event->ate_relid)
{
- if (event->dte_item[i].dti_state & TRIGGER_DEFERRED_DONE &&
- TransactionIdIsValid(event->dte_item[i].dti_done_xid) &&
- !(TransactionIdDidAbort(event->dte_item[i].dti_done_xid)))
- continue;
+ if (rel)
+ heap_close(rel, NoLock);
+ if (trigdesc)
+ FreeTriggerDesc(trigdesc);
+ if (finfo)
+ pfree(finfo);
/*
- * This trigger item hasn't been called yet. Check if we
- * should call it now.
+ * We assume that an appropriate lock is still held by
+ * the executor, so grab no new lock here.
*/
- if (immediate_only &&
- deferredTriggerCheckState(event->dte_item[i].dti_tgoid,
- event->dte_item[i].dti_state))
- {
- still_deferred_ones = true;
- continue;
- }
+ rel = heap_open(event->ate_relid, NoLock);
/*
- * So let's fire it... but first, open the correct
- * relation if this is not the same relation as before.
+ * Copy relation's trigger info so that we have a
+ * stable copy no matter what the called triggers do.
*/
- if (rel == NULL || rel->rd_id != event->dte_relid)
- {
- if (rel)
- heap_close(rel, NoLock);
- FreeTriggerDesc(trigdesc);
- if (finfo)
- pfree(finfo);
-
- /*
- * We assume that an appropriate lock is still held by
- * the executor, so grab no new lock here.
- */
- rel = heap_open(event->dte_relid, NoLock);
-
- /*
- * Copy relation's trigger info so that we have a
- * stable copy no matter what the called triggers do.
- */
- trigdesc = CopyTriggerDesc(rel->trigdesc);
-
- if (trigdesc == NULL) /* should not happen */
- elog(ERROR, "relation %u has no triggers",
- event->dte_relid);
-
- /*
- * Allocate space to cache fmgr lookup info for
- * triggers.
- */
- finfo = (FmgrInfo *)
- palloc0(trigdesc->numtriggers * sizeof(FmgrInfo));
- }
+ trigdesc = CopyTriggerDesc(rel->trigdesc);
+
+ if (trigdesc == NULL) /* should not happen */
+ elog(ERROR, "relation %u has no triggers",
+ event->ate_relid);
+
+ /*
+ * Allocate space to cache fmgr lookup info for
+ * triggers.
+ */
+ finfo = (FmgrInfo *)
+ palloc0(trigdesc->numtriggers * sizeof(FmgrInfo));
+ }
- DeferredTriggerExecute(event, i, rel, trigdesc, finfo,
- per_tuple_context);
+ /*
+ * Fire it. Note that the AFTER_TRIGGER_IN_PROGRESS flag is still
+ * set, so recursive examinations of the event list won't try
+ * to re-fire it.
+ */
+ AfterTriggerExecute(event, rel, trigdesc, finfo,
+ per_tuple_context);
- event->dte_item[i].dti_state |= TRIGGER_DEFERRED_DONE;
- event->dte_item[i].dti_done_xid = GetCurrentTransactionId();
- } /* end loop over items within event */
+ /*
+ * Mark the event as done.
+ */
+ event->ate_event &= ~AFTER_TRIGGER_IN_PROGRESS;
+ event->ate_event |= AFTER_TRIGGER_DONE;
}
/*
- * If it's now completely done, throw it away.
+ * If it's now done, throw it away, if allowed.
*
- * NB: it's possible the trigger calls above added more events to the
+ * NB: it's possible the trigger call above added more events to the
* queue, or that calls we will do later will want to add more, so
- * we have to be careful about maintaining list validity here.
+ * we have to be careful about maintaining list validity at all
+ * points here.
*/
- next_event = event->dte_next;
+ next_event = event->ate_next;
- if (still_deferred_ones || !immediate_only)
+ if ((event->ate_event & AFTER_TRIGGER_DONE) && delete_ok)
{
- /* Not done, keep in list */
- prev_event = event;
+ /* Delink it from list and free it */
+ if (prev_event)
+ prev_event->ate_next = next_event;
+ else
+ events->head = next_event;
+ pfree(event);
}
else
{
- /*
- * We can drop an item if it's done, but only if we're not
- * inside a subtransaction because it could abort later on. We
- * will want to check the item again if it does.
- */
- if (!IsSubTransaction())
- {
- /* delink it from list and free it */
- if (prev_event)
- prev_event->dte_next = next_event;
- else
- deferredTriggers->events = next_event;
- pfree(event);
- }
- else
- {
- /*
- * Mark the event-as-a-whole done, but keep it in the list.
- */
- event->dte_event |= TRIGGER_DEFERRED_DONE;
- event->dte_done_xid = GetCurrentTransactionId();
- prev_event = event;
- }
+ /* Keep it in list */
+ prev_event = event;
}
event = next_event;
}
/* Update list tail pointer in case we just deleted tail event */
- deferredTriggers->tail_thisxact = prev_event;
-
- /* Set the immediate event pointer for next time */
- deferredTriggers->events_imm = prev_event;
+ events->tail = prev_event;
/* Release working resources */
if (rel)
heap_close(rel, NoLock);
- FreeTriggerDesc(trigdesc);
+ if (trigdesc)
+ FreeTriggerDesc(trigdesc);
if (finfo)
pfree(finfo);
MemoryContextDelete(per_tuple_context);
}
+
/* ----------
- * DeferredTriggerBeginXact()
+ * AfterTriggerBeginXact()
*
* Called at transaction start (either BEGIN or implicit for single
* statement outside of transaction block).
* ----------
*/
void
-DeferredTriggerBeginXact(void)
+AfterTriggerBeginXact(void)
{
- Assert(deferredTriggers == NULL);
+ Assert(afterTriggers == NULL);
+
+ /*
+ * Build empty after-trigger state structure
+ */
+ afterTriggers = (AfterTriggers)
+ MemoryContextAlloc(TopTransactionContext,
+ sizeof(AfterTriggersData));
+
+ afterTriggers->firing_counter = FirstCommandId;
+ afterTriggers->state = SetConstraintStateCreate(8);
+ afterTriggers->events.head = NULL;
+ afterTriggers->events.tail = NULL;
+ afterTriggers->query_depth = -1;
- deferredTriggers = (DeferredTriggers)
+ /* We initialize the query stack to a reasonable size */
+ afterTriggers->query_stack = (AfterTriggerEventList *)
MemoryContextAlloc(TopTransactionContext,
- sizeof(DeferredTriggersData));
+ 8 * sizeof(AfterTriggerEventList));
+ afterTriggers->maxquerydepth = 8;
+
+ /* Subtransaction stack is empty until/unless needed */
+ afterTriggers->state_stack = NULL;
+ afterTriggers->events_stack = NULL;
+ afterTriggers->depth_stack = NULL;
+ afterTriggers->firing_stack = NULL;
+ afterTriggers->maxtransdepth = 0;
+}
+
+
+/* ----------
+ * AfterTriggerBeginQuery()
+ *
+ * Called just before we start processing a single query within a
+ * transaction (or subtransaction). Set up to record AFTER trigger
+ * events queued by the query. Note that it is allowed to have
+ * nested queries within a (sub)transaction.
+ * ----------
+ */
+void
+AfterTriggerBeginQuery(void)
+{
+ /* Must be inside a transaction */
+ Assert(afterTriggers != NULL);
+
+ /* Increase the query stack depth */
+ afterTriggers->query_depth++;
/*
- * If unspecified, constraints default to IMMEDIATE, per SQL
+ * Allocate more space in the query stack if needed.
*/
- deferredTriggers->state = DeferredTriggerStateCreate(8);
- deferredTriggers->events = NULL;
- deferredTriggers->events_imm = NULL;
- deferredTriggers->tail_thisxact = NULL;
- deferredTriggers->tail_stack = NULL;
- deferredTriggers->imm_stack = NULL;
- deferredTriggers->state_stack = NULL;
- deferredTriggers->numalloc = 0;
+ if (afterTriggers->query_depth >= afterTriggers->maxquerydepth)
+ {
+ /* repalloc will keep the stack in the same context */
+ int new_alloc = afterTriggers->maxquerydepth * 2;
+
+ afterTriggers->query_stack = (AfterTriggerEventList *)
+ repalloc(afterTriggers->query_stack,
+ new_alloc * sizeof(AfterTriggerEventList));
+ afterTriggers->maxquerydepth = new_alloc;
+ }
+
+ /* Initialize this query's list to empty */
+ afterTriggers->query_stack[afterTriggers->query_depth].head = NULL;
+ afterTriggers->query_stack[afterTriggers->query_depth].tail = NULL;
}
/* ----------
- * DeferredTriggerEndQuery()
+ * AfterTriggerEndQuery()
*
- * Called after one query sent down by the user has completely been
- * processed. At this time we invoke all outstanding IMMEDIATE triggers.
+ * Called after one query has been completely processed. At this time
+ * we invoke all AFTER IMMEDIATE trigger events queued by the query, and
+ * transfer deferred trigger events to the global deferred-trigger list.
* ----------
*/
void
-DeferredTriggerEndQuery(void)
+AfterTriggerEndQuery(void)
{
+ AfterTriggerEventList *events;
+
+ /* Must be inside a transaction */
+ Assert(afterTriggers != NULL);
+
+ /* Must be inside a query, too */
+ Assert(afterTriggers->query_depth >= 0);
+
/*
- * Ignore call if we aren't in a transaction.
+ * Process all immediate-mode triggers queued by the query, and move
+ * the deferred ones to the main list of deferred events.
+ *
+ * Notice that we decide which ones will be fired, and put the deferred
+ * ones on the main list, before anything is actually fired. This
+ * ensures reasonably sane behavior if a trigger function does
+ * SET CONSTRAINTS ... IMMEDIATE: all events we have decided to defer
+ * will be available for it to fire.
+ *
+ * If we find no firable events, we don't have to increment firing_counter.
*/
- if (deferredTriggers == NULL)
- return;
+ events = &afterTriggers->query_stack[afterTriggers->query_depth];
+ if (afterTriggerMarkEvents(events, &afterTriggers->events, true))
+ {
+ CommandId firing_id = afterTriggers->firing_counter++;
+
+ /* OK to delete the immediate events after processing them */
+ afterTriggerInvokeEvents(events, firing_id, true);
+ }
- deferredTriggerInvokeEvents(true);
+ afterTriggers->query_depth--;
}
/* ----------
- * DeferredTriggerEndXact()
+ * AfterTriggerEndXact()
*
* Called just before the current transaction is committed. At this
* time we invoke all DEFERRED triggers and tidy up.
* ----------
*/
void
-DeferredTriggerEndXact(void)
+AfterTriggerEndXact(void)
{
+ AfterTriggerEventList *events;
+
+ /* Must be inside a transaction */
+ Assert(afterTriggers != NULL);
+
+ /* ... but not inside a query */
+ Assert(afterTriggers->query_depth == -1);
+
/*
- * Ignore call if we aren't in a transaction.
+ * Run all the remaining triggers. Loop until they are all gone,
+ * just in case some trigger queues more for us to do.
*/
- if (deferredTriggers == NULL)
- return;
+ events = &afterTriggers->events;
+ while (afterTriggerMarkEvents(events, NULL, false))
+ {
+ CommandId firing_id = afterTriggers->firing_counter++;
- deferredTriggerInvokeEvents(false);
+ afterTriggerInvokeEvents(events, firing_id, true);
+ }
/*
- * Forget everything we know about deferred triggers.
+ * Forget everything we know about AFTER triggers.
*
* Since all the info is in TopTransactionContext or children thereof, we
* need do nothing special to reclaim memory.
*/
- deferredTriggers = NULL;
+ afterTriggers = NULL;
}
/* ----------
- * DeferredTriggerAbortXact()
+ * AfterTriggerAbortXact()
*
* The current transaction has entered the abort state.
* All outstanding triggers are canceled so we simply throw
@@ -2220,139 +2380,147 @@ DeferredTriggerEndXact(void)
* ----------
*/
void
-DeferredTriggerAbortXact(void)
+AfterTriggerAbortXact(void)
{
/*
- * Ignore call if we aren't in a transaction.
+ * Ignore call if we aren't in a transaction. (Need this to survive
+ * repeat call in case of error during transaction abort.)
*/
- if (deferredTriggers == NULL)
+ if (afterTriggers == NULL)
return;
/*
- * Forget everything we know about deferred triggers.
+ * Forget everything we know about AFTER triggers.
*
* Since all the info is in TopTransactionContext or children thereof, we
* need do nothing special to reclaim memory.
*/
- deferredTriggers = NULL;
+ afterTriggers = NULL;
}
/*
- * DeferredTriggerBeginSubXact()
+ * AfterTriggerBeginSubXact()
*
* Start a subtransaction.
*/
void
-DeferredTriggerBeginSubXact(void)
+AfterTriggerBeginSubXact(void)
{
int my_level = GetCurrentTransactionNestLevel();
/*
- * Ignore call if the transaction is in aborted state.
+ * Ignore call if the transaction is in aborted state. (Probably
+ * shouldn't happen?)
*/
- if (deferredTriggers == NULL)
+ if (afterTriggers == NULL)
return;
/*
* Allocate more space in the stacks if needed.
*/
- while (my_level >= deferredTriggers->numalloc)
+ while (my_level >= afterTriggers->maxtransdepth)
{
- if (deferredTriggers->numalloc == 0)
+ if (afterTriggers->maxtransdepth == 0)
{
MemoryContext old_cxt;
old_cxt = MemoryContextSwitchTo(TopTransactionContext);
#define DEFTRIG_INITALLOC 8
- deferredTriggers->tail_stack = (DeferredTriggerEvent *)
- palloc(DEFTRIG_INITALLOC * sizeof(DeferredTriggerEvent));
- deferredTriggers->imm_stack = (DeferredTriggerEvent *)
- palloc(DEFTRIG_INITALLOC * sizeof(DeferredTriggerEvent));
- deferredTriggers->state_stack = (DeferredTriggerState *)
- palloc(DEFTRIG_INITALLOC * sizeof(DeferredTriggerState));
- deferredTriggers->numalloc = DEFTRIG_INITALLOC;
+ afterTriggers->state_stack = (SetConstraintState *)
+ palloc(DEFTRIG_INITALLOC * sizeof(SetConstraintState));
+ afterTriggers->events_stack = (AfterTriggerEventList *)
+ palloc(DEFTRIG_INITALLOC * sizeof(AfterTriggerEventList));
+ afterTriggers->depth_stack = (int *)
+ palloc(DEFTRIG_INITALLOC * sizeof(int));
+ afterTriggers->firing_stack = (CommandId *)
+ palloc(DEFTRIG_INITALLOC * sizeof(CommandId));
+ afterTriggers->maxtransdepth = DEFTRIG_INITALLOC;
MemoryContextSwitchTo(old_cxt);
}
else
{
/* repalloc will keep the stacks in the same context */
- int new_alloc = deferredTriggers->numalloc * 2;
-
- deferredTriggers->tail_stack = (DeferredTriggerEvent *)
- repalloc(deferredTriggers->tail_stack,
- new_alloc * sizeof(DeferredTriggerEvent));
- deferredTriggers->imm_stack = (DeferredTriggerEvent *)
- repalloc(deferredTriggers->imm_stack,
- new_alloc * sizeof(DeferredTriggerEvent));
- deferredTriggers->state_stack = (DeferredTriggerState *)
- repalloc(deferredTriggers->state_stack,
- new_alloc * sizeof(DeferredTriggerState));
- deferredTriggers->numalloc = new_alloc;
+ int new_alloc = afterTriggers->maxtransdepth * 2;
+
+ afterTriggers->state_stack = (SetConstraintState *)
+ repalloc(afterTriggers->state_stack,
+ new_alloc * sizeof(SetConstraintState));
+ afterTriggers->events_stack = (AfterTriggerEventList *)
+ repalloc(afterTriggers->events_stack,
+ new_alloc * sizeof(AfterTriggerEventList));
+ afterTriggers->depth_stack = (int *)
+ repalloc(afterTriggers->depth_stack,
+ new_alloc * sizeof(int));
+ afterTriggers->firing_stack = (CommandId *)
+ repalloc(afterTriggers->firing_stack,
+ new_alloc * sizeof(CommandId));
+ afterTriggers->maxtransdepth = new_alloc;
}
}
/*
- * Push the current information into the stack.
+ * Push the current information into the stack. The SET CONSTRAINTS
+ * state is not saved until/unless changed.
*/
- deferredTriggers->tail_stack[my_level] = deferredTriggers->tail_thisxact;
- deferredTriggers->imm_stack[my_level] = deferredTriggers->events_imm;
- /* State is not saved until/unless changed */
- deferredTriggers->state_stack[my_level] = NULL;
+ afterTriggers->state_stack[my_level] = NULL;
+ afterTriggers->events_stack[my_level] = afterTriggers->events;
+ afterTriggers->depth_stack[my_level] = afterTriggers->query_depth;
+ afterTriggers->firing_stack[my_level] = afterTriggers->firing_counter;
}
/*
- * DeferredTriggerEndSubXact()
+ * AfterTriggerEndSubXact()
*
* The current subtransaction is ending.
*/
void
-DeferredTriggerEndSubXact(bool isCommit)
+AfterTriggerEndSubXact(bool isCommit)
{
int my_level = GetCurrentTransactionNestLevel();
- DeferredTriggerState state;
+ SetConstraintState state;
+ AfterTriggerEvent event;
+ CommandId subxact_firing_id;
/*
- * Ignore call if the transaction is in aborted state.
+ * Ignore call if the transaction is in aborted state. (Probably unneeded)
*/
- if (deferredTriggers == NULL)
+ if (afterTriggers == NULL)
return;
/*
* Pop the prior state if needed.
*/
- Assert(my_level < deferredTriggers->numalloc);
+ Assert(my_level < afterTriggers->maxtransdepth);
if (isCommit)
{
/* If we saved a prior state, we don't need it anymore */
- state = deferredTriggers->state_stack[my_level];
+ state = afterTriggers->state_stack[my_level];
if (state != NULL)
pfree(state);
/* this avoids double pfree if error later: */
- deferredTriggers->state_stack[my_level] = NULL;
+ afterTriggers->state_stack[my_level] = NULL;
+ Assert(afterTriggers->query_depth ==
+ afterTriggers->depth_stack[my_level]);
}
else
{
/*
* Aborting --- restore the pointers from the stacks.
*/
- deferredTriggers->tail_thisxact =
- deferredTriggers->tail_stack[my_level];
- deferredTriggers->events_imm =
- deferredTriggers->imm_stack[my_level];
+ afterTriggers->events = afterTriggers->events_stack[my_level];
+ afterTriggers->query_depth = afterTriggers->depth_stack[my_level];
/*
- * Cleanup the head and the tail of the list.
+ * Cleanup the tail of the list.
*/
- if (deferredTriggers->tail_thisxact == NULL)
- deferredTriggers->events = NULL;
- else
- deferredTriggers->tail_thisxact->dte_next = NULL;
+ if (afterTriggers->events.tail != NULL)
+ afterTriggers->events.tail->ate_next = NULL;
/*
- * We don't need to free the items, since the
+ * We don't need to free the subtransaction's items, since the
* CurTransactionContext will be reset shortly.
*/
@@ -2360,24 +2528,46 @@ DeferredTriggerEndSubXact(bool isCommit)
* Restore the trigger state. If the saved state is NULL, then
* this subxact didn't save it, so it doesn't need restoring.
*/
- state = deferredTriggers->state_stack[my_level];
+ state = afterTriggers->state_stack[my_level];
if (state != NULL)
{
- pfree(deferredTriggers->state);
- deferredTriggers->state = state;
+ pfree(afterTriggers->state);
+ afterTriggers->state = state;
}
/* this avoids double pfree if error later: */
- deferredTriggers->state_stack[my_level] = NULL;
+ afterTriggers->state_stack[my_level] = NULL;
+
+ /*
+ * Scan for any remaining deferred events that were marked DONE
+ * or IN PROGRESS by this subxact or a child, and un-mark them.
+ * We can recognize such events because they have a firing ID
+ * greater than or equal to the firing_counter value we saved at
+ * subtransaction start. (This essentially assumes that the
+ * current subxact includes all subxacts started after it.)
+ */
+ subxact_firing_id = afterTriggers->firing_stack[my_level];
+ for (event = afterTriggers->events.head;
+ event != NULL;
+ event = event->ate_next)
+ {
+ if (event->ate_event &
+ (AFTER_TRIGGER_DONE | AFTER_TRIGGER_IN_PROGRESS))
+ {
+ if (event->ate_firing_id >= subxact_firing_id)
+ event->ate_event &=
+ ~(AFTER_TRIGGER_DONE | AFTER_TRIGGER_IN_PROGRESS);
+ }
+ }
}
}
/*
- * Create an empty DeferredTriggerState with room for numalloc trigstates
+ * Create an empty SetConstraintState with room for numalloc trigstates
*/
-static DeferredTriggerState
-DeferredTriggerStateCreate(int numalloc)
+static SetConstraintState
+SetConstraintStateCreate(int numalloc)
{
- DeferredTriggerState state;
+ SetConstraintState state;
/* Behave sanely with numalloc == 0 */
if (numalloc <= 0)
@@ -2386,10 +2576,10 @@ DeferredTriggerStateCreate(int numalloc)
/*
* We assume that zeroing will correctly initialize the state values.
*/
- state = (DeferredTriggerState)
+ state = (SetConstraintState)
MemoryContextAllocZero(TopTransactionContext,
- sizeof(DeferredTriggerStateData) +
- (numalloc - 1) *sizeof(DeferredTriggerStatusData));
+ sizeof(SetConstraintStateData) +
+ (numalloc - 1) *sizeof(SetConstraintTriggerData));
state->numalloc = numalloc;
@@ -2397,67 +2587,67 @@ DeferredTriggerStateCreate(int numalloc)
}
/*
- * Copy a DeferredTriggerState
+ * Copy a SetConstraintState
*/
-static DeferredTriggerState
-DeferredTriggerStateCopy(DeferredTriggerState origstate)
+static SetConstraintState
+SetConstraintStateCopy(SetConstraintState origstate)
{
- DeferredTriggerState state;
+ SetConstraintState state;
- state = DeferredTriggerStateCreate(origstate->numstates);
+ state = SetConstraintStateCreate(origstate->numstates);
state->all_isset = origstate->all_isset;
state->all_isdeferred = origstate->all_isdeferred;
state->numstates = origstate->numstates;
memcpy(state->trigstates, origstate->trigstates,
- origstate->numstates * sizeof(DeferredTriggerStatusData));
+ origstate->numstates * sizeof(SetConstraintTriggerData));
return state;
}
/*
- * Add a per-trigger item to a DeferredTriggerState. Returns possibly-changed
+ * Add a per-trigger item to a SetConstraintState. Returns possibly-changed
* pointer to the state object (it will change if we have to repalloc).
*/
-static DeferredTriggerState
-DeferredTriggerStateAddItem(DeferredTriggerState state,
- Oid tgoid, bool tgisdeferred)
+static SetConstraintState
+SetConstraintStateAddItem(SetConstraintState state,
+ Oid tgoid, bool tgisdeferred)
{
if (state->numstates >= state->numalloc)
{
int newalloc = state->numalloc * 2;
newalloc = Max(newalloc, 8); /* in case original has size 0 */
- state = (DeferredTriggerState)
+ state = (SetConstraintState)
repalloc(state,
- sizeof(DeferredTriggerStateData) +
- (newalloc - 1) *sizeof(DeferredTriggerStatusData));
+ sizeof(SetConstraintStateData) +
+ (newalloc - 1) *sizeof(SetConstraintTriggerData));
state->numalloc = newalloc;
Assert(state->numstates < state->numalloc);
}
- state->trigstates[state->numstates].dts_tgoid = tgoid;
- state->trigstates[state->numstates].dts_tgisdeferred = tgisdeferred;
+ state->trigstates[state->numstates].sct_tgoid = tgoid;
+ state->trigstates[state->numstates].sct_tgisdeferred = tgisdeferred;
state->numstates++;
return state;
}
/* ----------
- * DeferredTriggerSetState()
+ * AfterTriggerSetState()
*
- * Called for the SET CONSTRAINTS ... utility command.
+ * Execute the SET CONSTRAINTS ... utility command.
* ----------
*/
void
-DeferredTriggerSetState(ConstraintsSetStmt *stmt)
+AfterTriggerSetState(ConstraintsSetStmt *stmt)
{
int my_level = GetCurrentTransactionNestLevel();
/*
- * Ignore call if we aren't in a transaction.
+ * Ignore call if we aren't in a transaction. (Shouldn't happen?)
*/
- if (deferredTriggers == NULL)
+ if (afterTriggers == NULL)
return;
/*
@@ -2466,10 +2656,10 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
* aborts.
*/
if (my_level > 1 &&
- deferredTriggers->state_stack[my_level] == NULL)
+ afterTriggers->state_stack[my_level] == NULL)
{
- deferredTriggers->state_stack[my_level] =
- DeferredTriggerStateCopy(deferredTriggers->state);
+ afterTriggers->state_stack[my_level] =
+ SetConstraintStateCopy(afterTriggers->state);
}
/*
@@ -2480,13 +2670,13 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
/*
* Forget any previous SET CONSTRAINTS commands in this transaction.
*/
- deferredTriggers->state->numstates = 0;
+ afterTriggers->state->numstates = 0;
/*
* Set the per-transaction ALL state to known.
*/
- deferredTriggers->state->all_isset = true;
- deferredTriggers->state->all_isdeferred = stmt->deferred;
+ afterTriggers->state->all_isset = true;
+ afterTriggers->state->all_isdeferred = stmt->deferred;
}
else
{
@@ -2569,29 +2759,28 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
heap_close(tgrel, AccessShareLock);
/*
- * Inside of a transaction block set the trigger states of
- * individual triggers on transaction level.
+ * Set the trigger states of individual triggers for this xact.
*/
foreach(l, oidlist)
{
Oid tgoid = lfirst_oid(l);
- DeferredTriggerState state = deferredTriggers->state;
+ SetConstraintState state = afterTriggers->state;
bool found = false;
int i;
for (i = 0; i < state->numstates; i++)
{
- if (state->trigstates[i].dts_tgoid == tgoid)
+ if (state->trigstates[i].sct_tgoid == tgoid)
{
- state->trigstates[i].dts_tgisdeferred = stmt->deferred;
+ state->trigstates[i].sct_tgisdeferred = stmt->deferred;
found = true;
break;
}
}
if (!found)
{
- deferredTriggers->state =
- DeferredTriggerStateAddItem(state, tgoid, stmt->deferred);
+ afterTriggers->state =
+ SetConstraintStateAddItem(state, tgoid, stmt->deferred);
}
}
}
@@ -2600,20 +2789,35 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
* SQL99 requires that when a constraint is set to IMMEDIATE, any
* deferred checks against that constraint must be made when the SET
* CONSTRAINTS command is executed -- i.e. the effects of the SET
- * CONSTRAINTS command applies retroactively. This happens "for free"
- * since we have already made the necessary modifications to the
- * constraints, and deferredTriggerEndQuery() is called by
- * finish_xact_command(). But we must reset
- * deferredTriggerInvokeEvents' tail pointer to make it rescan the
- * entire list, in case some deferred events are now immediately
- * invokable.
+ * CONSTRAINTS command apply retroactively. We've updated the
+ * constraints state, so scan the list of previously deferred events
+ * to fire any that have now become immediate.
+ *
+ * Obviously, if this was SET ... DEFERRED then it can't have converted
+ * any unfired events to immediate, so we need do nothing in that case.
*/
- deferredTriggers->events_imm = NULL;
+ if (!stmt->deferred)
+ {
+ AfterTriggerEventList *events = &afterTriggers->events;
+
+ if (afterTriggerMarkEvents(events, NULL, true))
+ {
+ CommandId firing_id = afterTriggers->firing_counter++;
+
+ /*
+ * We can delete fired events if we are at top transaction
+ * level, but we'd better not if inside a subtransaction, since
+ * the subtransaction could later get rolled back.
+ */
+ afterTriggerInvokeEvents(events, firing_id,
+ !IsSubTransaction());
+ }
+ }
}
/* ----------
- * DeferredTriggerSaveEvent()
+ * AfterTriggerSaveEvent()
*
* Called by ExecA[RS]...Triggers() to add the event to the queue.
*
@@ -2622,23 +2826,20 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
* ----------
*/
static void
-DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
- HeapTuple oldtup, HeapTuple newtup)
+AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
+ HeapTuple oldtup, HeapTuple newtup)
{
Relation rel = relinfo->ri_RelationDesc;
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
- MemoryContext oldcxt;
- DeferredTriggerEvent new_event;
- int new_size;
+ AfterTriggerEvent new_event;
int i;
int ntriggers;
- int n_enabled_triggers = 0;
int *tgindx;
ItemPointerData oldctid;
ItemPointerData newctid;
- if (deferredTriggers == NULL)
- elog(ERROR, "DeferredTriggerSaveEvent() called outside of transaction");
+ if (afterTriggers == NULL)
+ elog(ERROR, "AfterTriggerSaveEvent() called outside of transaction");
/*
* Get the CTID's of OLD and NEW
@@ -2652,6 +2853,9 @@ DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
else
ItemPointerSetInvalid(&(newctid));
+ /*
+ * Scan the appropriate set of triggers
+ */
if (row_trigger)
{
ntriggers = trigdesc->n_after_row[event];
@@ -2663,137 +2867,80 @@ DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
tgindx = trigdesc->tg_after_statement[event];
}
- /*
- * Count the number of triggers that are actually enabled. Since we
- * only add enabled triggers to the queue, we only need allocate
- * enough space to hold them (and not any disabled triggers that may
- * be associated with the relation).
- */
for (i = 0; i < ntriggers; i++)
{
Trigger *trigger = &trigdesc->triggers[tgindx[i]];
- if (trigger->tgenabled)
- n_enabled_triggers++;
- }
-
- /*
- * If all the triggers on this relation are disabled, we're done.
- */
- if (n_enabled_triggers == 0)
- return;
-
- /*
- * Create a new event. We use the CurTransactionContext so the event
- * will automatically go away if the subtransaction aborts.
- */
- oldcxt = MemoryContextSwitchTo(CurTransactionContext);
-
- new_size = offsetof(DeferredTriggerEventData, dte_item[0]) +
- n_enabled_triggers * sizeof(DeferredTriggerEventItem);
-
- new_event = (DeferredTriggerEvent) palloc(new_size);
- new_event->dte_next = NULL;
- new_event->dte_event = event & TRIGGER_EVENT_OPMASK;
- new_event->dte_done_xid = InvalidTransactionId;
- if (row_trigger)
- new_event->dte_event |= TRIGGER_EVENT_ROW;
- new_event->dte_relid = rel->rd_id;
- ItemPointerCopy(&oldctid, &(new_event->dte_oldctid));
- ItemPointerCopy(&newctid, &(new_event->dte_newctid));
- new_event->dte_n_items = ntriggers;
- for (i = 0; i < ntriggers; i++)
- {
- DeferredTriggerEventItem *ev_item;
- Trigger *trigger = &trigdesc->triggers[tgindx[i]];
-
+ /* Ignore disabled triggers */
if (!trigger->tgenabled)
continue;
- ev_item = &(new_event->dte_item[i]);
- ev_item->dti_tgoid = trigger->tgoid;
- ev_item->dti_done_xid = InvalidTransactionId;
- ev_item->dti_state =
- ((trigger->tgdeferrable) ?
- TRIGGER_DEFERRED_DEFERRABLE : 0) |
- ((trigger->tginitdeferred) ?
- TRIGGER_DEFERRED_INITDEFERRED : 0);
-
- if (row_trigger && (trigdesc->n_before_row[event] > 0))
- ev_item->dti_state |= TRIGGER_DEFERRED_HAS_BEFORE;
- else if (!row_trigger && (trigdesc->n_before_statement[event] > 0))
- ev_item->dti_state |= TRIGGER_DEFERRED_HAS_BEFORE;
- }
-
- MemoryContextSwitchTo(oldcxt);
+ /*
+ * If it is an RI UPDATE trigger, and the referenced keys have
+ * not changed, short-circuit queuing of the event; there's no
+ * need to fire the trigger.
+ */
+ if ((event & TRIGGER_EVENT_OPMASK) == TRIGGER_EVENT_UPDATE)
+ {
+ bool is_ri_trigger;
- switch (event & TRIGGER_EVENT_OPMASK)
- {
- case TRIGGER_EVENT_INSERT:
- /* nothing to do */
- break;
+ switch (trigger->tgfoid)
+ {
+ case F_RI_FKEY_NOACTION_UPD:
+ case F_RI_FKEY_CASCADE_UPD:
+ case F_RI_FKEY_RESTRICT_UPD:
+ case F_RI_FKEY_SETNULL_UPD:
+ case F_RI_FKEY_SETDEFAULT_UPD:
+ is_ri_trigger = true;
+ break;
- case TRIGGER_EVENT_UPDATE:
+ default:
+ is_ri_trigger = false;
+ break;
+ }
- /*
- * Check if one of the referenced keys is changed.
- */
- for (i = 0; i < ntriggers; i++)
+ if (is_ri_trigger)
{
- Trigger *trigger = &trigdesc->triggers[tgindx[i]];
- bool is_ri_trigger;
- bool key_unchanged;
TriggerData LocTriggerData;
- /*
- * We are interested in RI_FKEY triggers only.
- */
- switch (trigger->tgfoid)
- {
- case F_RI_FKEY_NOACTION_UPD:
- case F_RI_FKEY_CASCADE_UPD:
- case F_RI_FKEY_RESTRICT_UPD:
- case F_RI_FKEY_SETNULL_UPD:
- case F_RI_FKEY_SETDEFAULT_UPD:
- is_ri_trigger = true;
- break;
-
- default:
- is_ri_trigger = false;
- break;
- }
- if (!is_ri_trigger)
- continue;
-
LocTriggerData.type = T_TriggerData;
- LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE;
+ LocTriggerData.tg_event =
+ TRIGGER_EVENT_UPDATE | TRIGGER_EVENT_ROW;
LocTriggerData.tg_relation = rel;
LocTriggerData.tg_trigtuple = oldtup;
LocTriggerData.tg_newtuple = newtup;
LocTriggerData.tg_trigger = trigger;
- key_unchanged = RI_FKey_keyequal_upd(&LocTriggerData);
-
- if (key_unchanged)
+ if (RI_FKey_keyequal_upd(&LocTriggerData))
{
- /*
- * The key hasn't changed, so no need later to invoke
- * the trigger at all.
- */
- new_event->dte_item[i].dti_state |= TRIGGER_DEFERRED_DONE;
- new_event->dte_item[i].dti_done_xid = GetCurrentTransactionId();
+ /* key unchanged, so skip queuing this event */
+ continue;
}
}
+ }
- break;
+ /*
+ * Create a new event. We use the CurTransactionContext so the event
+ * will automatically go away if the subtransaction aborts.
+ */
+ new_event = (AfterTriggerEvent)
+ MemoryContextAlloc(CurTransactionContext,
+ sizeof(AfterTriggerEventData));
+ new_event->ate_next = NULL;
+ new_event->ate_event =
+ (event & TRIGGER_EVENT_OPMASK) |
+ (row_trigger ? TRIGGER_EVENT_ROW : 0) |
+ (trigger->tgdeferrable ? AFTER_TRIGGER_DEFERRABLE : 0) |
+ (trigger->tginitdeferred ? AFTER_TRIGGER_INITDEFERRED : 0);
+ new_event->ate_firing_id = 0;
+ new_event->ate_tgoid = trigger->tgoid;
+ new_event->ate_relid = rel->rd_id;
+ ItemPointerCopy(&oldctid, &(new_event->ate_oldctid));
+ ItemPointerCopy(&newctid, &(new_event->ate_newctid));
- case TRIGGER_EVENT_DELETE:
- /* nothing to do */
- break;
+ /*
+ * Add the new event to the queue.
+ */
+ afterTriggerAddEvent(new_event);
}
-
- /*
- * Add the new event to the queue.
- */
- deferredTriggerAddEvent(new_event);
}
diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index 2a9e5d88a9e..3611c85a5fc 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/executor/functions.c,v 1.87 2004/09/06 18:10:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/functions.c,v 1.88 2004/09/10 18:39:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -17,6 +17,7 @@
#include "access/heapam.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
+#include "commands/trigger.h"
#include "executor/execdefs.h"
#include "executor/executor.h"
#include "executor/functions.h"
@@ -273,7 +274,10 @@ postquel_start(execution_state *es, SQLFunctionCachePtr fcache)
/* Utility commands don't need Executor. */
if (es->qd->operation != CMD_UTILITY)
+ {
+ AfterTriggerBeginQuery();
ExecutorStart(es->qd, false, false);
+ }
es->status = F_EXEC_RUN;
}
@@ -316,7 +320,10 @@ postquel_end(execution_state *es)
/* Utility commands don't need Executor. */
if (es->qd->operation != CMD_UTILITY)
+ {
ExecutorEnd(es->qd);
+ AfterTriggerEndQuery();
+ }
FreeQueryDesc(es->qd);
es->qd = NULL;
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 4ffb27b0139..636eed31eee 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.125 2004/08/29 05:06:42 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.126 2004/09/10 18:39:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -16,6 +16,7 @@
#include "access/printtup.h"
#include "catalog/heap.h"
+#include "commands/trigger.h"
#include "executor/spi_priv.h"
#include "tcop/tcopprot.h"
#include "utils/lsyscache.h"
@@ -1434,6 +1435,8 @@ _SPI_pquery(QueryDesc *queryDesc, bool runit,
ResetUsage();
#endif
+ AfterTriggerBeginQuery();
+
ExecutorStart(queryDesc, useCurrentSnapshot, false);
ExecutorRun(queryDesc, ForwardScanDirection, (long) tcount);
@@ -1447,6 +1450,11 @@ _SPI_pquery(QueryDesc *queryDesc, bool runit,
elog(ERROR, "consistency check on SPI tuple count failed");
}
+ ExecutorEnd(queryDesc);
+
+ /* Take care of any queued AFTER triggers */
+ AfterTriggerEndQuery();
+
if (queryDesc->dest->mydest == SPI)
{
SPI_processed = _SPI_current->processed;
@@ -1459,8 +1467,6 @@ _SPI_pquery(QueryDesc *queryDesc, bool runit,
res = SPI_OK_UTILITY;
}
- ExecutorEnd(queryDesc);
-
FreeQueryDesc(queryDesc);
#ifdef SPI_EXECUTOR_STATS
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index a3a96efae9c..50364bd79d3 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.430 2004/08/29 05:06:49 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.431 2004/09/10 18:39:59 tgl Exp $
*
* NOTES
* this is the "main" module of the postgres backend and
@@ -1823,9 +1823,6 @@ finish_xact_command(void)
{
if (xact_started)
{
- /* Invoke IMMEDIATE constraint triggers */
- DeferredTriggerEndQuery();
-
/* Cancel any active statement timeout before committing */
disable_sig_alarm(true);
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index 5d9fe611f01..fca98fc0fa5 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -8,13 +8,14 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.85 2004/08/29 05:06:49 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.86 2004/09/10 18:40:00 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
+#include "commands/trigger.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "tcop/tcopprot.h"
@@ -136,6 +137,11 @@ ProcessQuery(Query *parsetree,
*/
queryDesc = CreateQueryDesc(parsetree, plan, dest, params, false);
+ /*
+ * Set up to collect AFTER triggers
+ */
+ AfterTriggerBeginQuery();
+
/*
* Call ExecStart to prepare the plan for execution
*/
@@ -185,6 +191,9 @@ ProcessQuery(Query *parsetree,
*/
ExecutorEnd(queryDesc);
+ /* And take care of any queued AFTER triggers */
+ AfterTriggerEndQuery();
+
FreeQueryDesc(queryDesc);
}
@@ -290,6 +299,13 @@ PortalStart(Portal portal, ParamListInfo params)
params,
false);
+ /*
+ * We do *not* call AfterTriggerBeginQuery() here. We
+ * assume that a SELECT cannot queue any triggers. It
+ * would be messy to support triggers since the execution
+ * of the portal may be interleaved with other queries.
+ */
+
/*
* Call ExecStart to prepare the plan for execution
*/
@@ -1144,8 +1160,8 @@ DoPortalRunFetch(Portal portal,
return PortalRunSelect(portal, false, 1L, dest);
}
else
-/* count == 0 */
{
+ /* count == 0 */
/* Rewind to start, return zero rows */
DoPortalRewind(portal);
return PortalRunSelect(portal, true, 0L, dest);
@@ -1173,8 +1189,8 @@ DoPortalRunFetch(Portal portal,
return PortalRunSelect(portal, false, 1L, dest);
}
else
-/* count == 0 */
{
+ /* count == 0 */
/* Same as FETCH FORWARD 0, so fall out of switch */
fdirection = FETCH_FORWARD;
}
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 517266b649c..6aec17bf9a5 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.228 2004/08/29 05:06:49 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.229 2004/09/10 18:40:00 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -912,7 +912,7 @@ ProcessUtility(Node *parsetree,
break;
case T_ConstraintsSetStmt:
- DeferredTriggerSetState((ConstraintsSetStmt *) parsetree);
+ AfterTriggerSetState((ConstraintsSetStmt *) parsetree);
break;
case T_CreateGroupStmt:
diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 8aaa38ddb69..9c32d57c111 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -17,7 +17,7 @@
*
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.71 2004/08/29 05:06:49 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.72 2004/09/10 18:40:04 tgl Exp $
*
* ----------
*/
@@ -2454,7 +2454,7 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
*
* Check if we have a key change on update.
*
- * This is not a real trigger procedure. It is used by the deferred
+ * This is not a real trigger procedure. It is used by the AFTER
* trigger queue manager to detect "triggered data change violation".
* ----------
*/
diff --git a/src/include/commands/trigger.h b/src/include/commands/trigger.h
index f23889668c1..7d5569018ae 100644
--- a/src/include/commands/trigger.h
+++ b/src/include/commands/trigger.h
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.48 2004/08/29 05:06:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.49 2004/09/10 18:40:06 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -45,11 +45,12 @@ typedef struct TriggerData
#define TRIGGER_EVENT_ROW 0x00000004
#define TRIGGER_EVENT_BEFORE 0x00000008
-#define TRIGGER_DEFERRED_DONE 0x00000010
-#define TRIGGER_DEFERRED_CANCELED 0x00000020
-#define TRIGGER_DEFERRED_DEFERRABLE 0x00000040
-#define TRIGGER_DEFERRED_INITDEFERRED 0x00000080
-#define TRIGGER_DEFERRED_HAS_BEFORE 0x00000100
+/* More TriggerEvent flags, used only within trigger.c */
+
+#define AFTER_TRIGGER_DONE 0x00000010
+#define AFTER_TRIGGER_IN_PROGRESS 0x00000020
+#define AFTER_TRIGGER_DEFERRABLE 0x00000040
+#define AFTER_TRIGGER_INITDEFERRED 0x00000080
#define TRIGGER_FIRED_BY_INSERT(event) \
(((TriggerEvent) (event) & TRIGGER_EVENT_OPMASK) == \
@@ -151,14 +152,15 @@ extern void ExecARUpdateTriggers(EState *estate,
ItemPointer tupleid,
HeapTuple newtuple);
-extern void DeferredTriggerBeginXact(void);
-extern void DeferredTriggerEndQuery(void);
-extern void DeferredTriggerEndXact(void);
-extern void DeferredTriggerAbortXact(void);
-extern void DeferredTriggerBeginSubXact(void);
-extern void DeferredTriggerEndSubXact(bool isCommit);
+extern void AfterTriggerBeginXact(void);
+extern void AfterTriggerBeginQuery(void);
+extern void AfterTriggerEndQuery(void);
+extern void AfterTriggerEndXact(void);
+extern void AfterTriggerAbortXact(void);
+extern void AfterTriggerBeginSubXact(void);
+extern void AfterTriggerEndSubXact(bool isCommit);
-extern void DeferredTriggerSetState(ConstraintsSetStmt *stmt);
+extern void AfterTriggerSetState(ConstraintsSetStmt *stmt);
/*
diff --git a/src/test/regress/expected/foreign_key.out b/src/test/regress/expected/foreign_key.out
index b291000add1..e954a232f1b 100644
--- a/src/test/regress/expected/foreign_key.out
+++ b/src/test/regress/expected/foreign_key.out
@@ -646,6 +646,7 @@ SELECT * from FKTABLE;
UPDATE PKTABLE set ptest2=5 where ptest2=2;
ERROR: insert or update on table "fktable" violates foreign key constraint "constrname3"
DETAIL: Key (ftest1,ftest2,ftest3)=(1,-1,3) is not present in table "pktable".
+CONTEXT: SQL query "UPDATE ONLY "public"."fktable" SET "ftest2" = DEFAULT WHERE "ftest1" = $1 AND "ftest2" = $2 AND "ftest3" = $3"
-- Try to update something that will set default
UPDATE PKTABLE set ptest1=0, ptest2=5, ptest3=10 where ptest2=2;
UPDATE PKTABLE set ptest2=10 where ptest2=4;
diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index 73962dbb37a..50d72830fb4 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -1935,3 +1935,74 @@ select * from foo;
20
(2 rows)
+--
+-- test foreign key error trapping
+--
+create temp table master(f1 int primary key);
+NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "master_pkey" for table "master"
+create temp table slave(f1 int references master deferrable);
+insert into master values(1);
+insert into slave values(1);
+insert into slave values(2); -- fails
+ERROR: insert or update on table "slave" violates foreign key constraint "slave_f1_fkey"
+DETAIL: Key (f1)=(2) is not present in table "master".
+create function trap_foreign_key(int) returns int as $$
+begin
+ begin -- start a subtransaction
+ insert into slave values($1);
+ exception
+ when foreign_key_violation then
+ raise notice 'caught foreign_key_violation';
+ return 0;
+ end;
+ return 1;
+end$$ language plpgsql;
+create function trap_foreign_key_2() returns int as $$
+begin
+ begin -- start a subtransaction
+ set constraints all immediate;
+ exception
+ when foreign_key_violation then
+ raise notice 'caught foreign_key_violation';
+ return 0;
+ end;
+ return 1;
+end$$ language plpgsql;
+select trap_foreign_key(1);
+ trap_foreign_key
+------------------
+ 1
+(1 row)
+
+select trap_foreign_key(2); -- detects FK violation
+NOTICE: caught foreign_key_violation
+ trap_foreign_key
+------------------
+ 0
+(1 row)
+
+begin;
+ set constraints all deferred;
+ select trap_foreign_key(2); -- should not detect FK violation
+ trap_foreign_key
+------------------
+ 1
+(1 row)
+
+ savepoint x;
+ set constraints all immediate; -- fails
+ERROR: insert or update on table "slave" violates foreign key constraint "slave_f1_fkey"
+DETAIL: Key (f1)=(2) is not present in table "master".
+ rollback to x;
+ select trap_foreign_key_2(); -- detects FK violation
+NOTICE: caught foreign_key_violation
+ trap_foreign_key_2
+--------------------
+ 0
+(1 row)
+
+commit; -- still fails
+ERROR: insert or update on table "slave" violates foreign key constraint "slave_f1_fkey"
+DETAIL: Key (f1)=(2) is not present in table "master".
+drop function trap_foreign_key(int);
+drop function trap_foreign_key_2();
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index 948a02ac0e2..a8951cd6efa 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -1699,3 +1699,54 @@ select blockme();
reset statement_timeout;
select * from foo;
+
+--
+-- test foreign key error trapping
+--
+
+create temp table master(f1 int primary key);
+
+create temp table slave(f1 int references master deferrable);
+
+insert into master values(1);
+insert into slave values(1);
+insert into slave values(2); -- fails
+
+create function trap_foreign_key(int) returns int as $$
+begin
+ begin -- start a subtransaction
+ insert into slave values($1);
+ exception
+ when foreign_key_violation then
+ raise notice 'caught foreign_key_violation';
+ return 0;
+ end;
+ return 1;
+end$$ language plpgsql;
+
+create function trap_foreign_key_2() returns int as $$
+begin
+ begin -- start a subtransaction
+ set constraints all immediate;
+ exception
+ when foreign_key_violation then
+ raise notice 'caught foreign_key_violation';
+ return 0;
+ end;
+ return 1;
+end$$ language plpgsql;
+
+select trap_foreign_key(1);
+select trap_foreign_key(2); -- detects FK violation
+
+begin;
+ set constraints all deferred;
+ select trap_foreign_key(2); -- should not detect FK violation
+ savepoint x;
+ set constraints all immediate; -- fails
+ rollback to x;
+ select trap_foreign_key_2(); -- detects FK violation
+commit; -- still fails
+
+drop function trap_foreign_key(int);
+drop function trap_foreign_key_2();
--
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