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Support deferrable uniqueness constraints.

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The current implementation fires an AFTER ROW trigger for each tuple that
looks like it might be non-unique according to the index contents at the
time of insertion.  This works well as long as there aren't many conflicts,
but won't scale to massive unique-key reassignments.  Improving that case
is a TODO item.

Dean Rasheed
This commit is contained in:
Tom Lane
2009-07-29 20:56:21 +00:00
parent 8504905793
commit 25d9bf2e3e
51 changed files with 1241 additions and 245 deletions
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64
src/backend/commands/trigger.c
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.249 2009/07/28 02:56:30 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.250 2009/07/29 20:56:18 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -63,7 +63,8 @@ static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
Instrumentation *instr,
MemoryContext per_tuple_context);
static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
bool row_trigger, HeapTuple oldtup, HeapTuple newtup);
bool row_trigger, HeapTuple oldtup, HeapTuple newtup,
List *recheckIndexes);
/*
@ -77,6 +78,10 @@ static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
* indexOid, if nonzero, is the OID of an index associated with the constraint.
* We do nothing with this except store it into pg_trigger.tgconstrindid.
*
* prefix is NULL for user-created triggers. For internally generated
* constraint triggers, it is a prefix string to use in building the
* trigger name. (stmt->trigname is the constraint name in such cases.)
*
* If checkPermissions is true we require ACL_TRIGGER permissions on the
* relation. If not, the caller already checked permissions. (This is
* currently redundant with constraintOid being zero, but it's clearer to
@ -87,7 +92,7 @@ static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
*/
Oid
CreateTrigger(CreateTrigStmt *stmt,
Oid constraintOid, Oid indexOid,
Oid constraintOid, Oid indexOid, const char *prefix,
bool checkPermissions)
{
int16 tgtype;
@ -216,20 +221,20 @@ CreateTrigger(CreateTrigStmt *stmt,
trigoid = GetNewOid(tgrel);
/*
* If trigger is for an RI constraint, the passed-in name is the
* constraint name; save that and build a unique trigger name to avoid
* collisions with user-selected trigger names.
* If trigger is for a constraint, stmt->trigname is the constraint
* name; save that and build a unique trigger name based on the supplied
* prefix, to avoid collisions with user-selected trigger names.
*/
if (OidIsValid(constraintOid))
if (prefix != NULL)
{
snprintf(constrtrigname, sizeof(constrtrigname),
"RI_ConstraintTrigger_%u", trigoid);
"%s_%u", prefix, trigoid);
trigname = constrtrigname;
constrname = stmt->trigname;
}
else if (stmt->isconstraint)
{
/* constraint trigger: trigger name is also constraint name */
/* user constraint trigger: trigger name is also constraint name */
trigname = stmt->trigname;
constrname = stmt->trigname;
}
@ -1650,7 +1655,7 @@ ExecASInsertTriggers(EState *estate, ResultRelInfo *relinfo)
if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_INSERT] > 0)
AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
false, NULL, NULL);
false, NULL, NULL, NIL);
}
HeapTuple
@ -1706,13 +1711,13 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
void
ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,
HeapTuple trigtuple)
HeapTuple trigtuple, List *recheckIndexes)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc && trigdesc->n_after_row[TRIGGER_EVENT_INSERT] > 0)
AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
true, NULL, trigtuple);
true, NULL, trigtuple, recheckIndexes);
}
void
@ -1781,7 +1786,7 @@ ExecASDeleteTriggers(EState *estate, ResultRelInfo *relinfo)
if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_DELETE] > 0)
AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
false, NULL, NULL);
false, NULL, NULL, NIL);
}
bool
@ -1858,7 +1863,7 @@ ExecARDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
tupleid, NULL);
AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
true, trigtuple, NULL);
true, trigtuple, NULL, NIL);
heap_freetuple(trigtuple);
}
}
@ -1929,7 +1934,7 @@ ExecASUpdateTriggers(EState *estate, ResultRelInfo *relinfo)
if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_UPDATE] > 0)
AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
false, NULL, NULL);
false, NULL, NULL, NIL);
}
HeapTuple
@ -1999,7 +2004,8 @@ ExecBRUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
void
ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
ItemPointer tupleid, HeapTuple newtuple)
ItemPointer tupleid, HeapTuple newtuple,
List *recheckIndexes)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
@ -2009,7 +2015,7 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
tupleid, NULL);
AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
true, trigtuple, newtuple);
true, trigtuple, newtuple, recheckIndexes);
heap_freetuple(trigtuple);
}
}
@ -2080,7 +2086,7 @@ ExecASTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_TRUNCATE] > 0)
AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_TRUNCATE,
false, NULL, NULL);
false, NULL, NULL, NIL);
}
@ -3793,15 +3799,18 @@ AfterTriggerPendingOnRel(Oid relid)
/* ----------
* AfterTriggerSaveEvent()
*
* Called by ExecA[RS]...Triggers() to add the event to the queue.
* Called by ExecA[RS]...Triggers() to queue up the triggers that should
* be fired for an event.
*
* NOTE: should be called only if we've determined that an event must
* be added to the queue.
* NOTE: this is called whenever there are any triggers associated with
* the event (even if they are disabled). This function decides which
* triggers actually need to be queued.
* ----------
*/
static void
AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
HeapTuple oldtup, HeapTuple newtup)
HeapTuple oldtup, HeapTuple newtup,
List *recheckIndexes)
{
Relation rel = relinfo->ri_RelationDesc;
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
@ -3961,6 +3970,17 @@ AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
}
}
/*
* If the trigger is a deferred unique constraint check trigger,
* only queue it if the unique constraint was potentially violated,
* which we know from index insertion time.
*/
if (trigger->tgfoid == F_UNIQUE_KEY_RECHECK)
{
if (!list_member_oid(recheckIndexes, trigger->tgconstrindid))
continue; /* Uniqueness definitely not violated */
}
/*
* Fill in event structure and add it to the current query's queue.
*/