Support statement-level ON TRUNCATE triggers. Simon Riggs

16 files changed, 359 insertions, 29 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1754484eeeb..e97a4fc13aa 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.248 2008/03/27 03:57:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.249 2008/03/28 00:21:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -539,6 +539,9 @@ ExecuteTruncate(TruncateStmt *stmt)
 {
 	List	   *rels = NIL;
 	List	   *relids = NIL;
+	EState	   *estate;
+	ResultRelInfo *resultRelInfos;
+	ResultRelInfo *resultRelInfo;
 	ListCell   *cell;
 
 	/*
@@ -601,6 +604,45 @@ ExecuteTruncate(TruncateStmt *stmt)
 		heap_truncate_check_FKs(rels, false);
 #endif
 
+	/* Prepare to catch AFTER triggers. */
+	AfterTriggerBeginQuery();
+
+	/*
+	 * To fire triggers, we'll need an EState as well as a ResultRelInfo
+	 * for each relation.
+	 */
+	estate = CreateExecutorState();
+	resultRelInfos = (ResultRelInfo *)
+		palloc(list_length(rels) * sizeof(ResultRelInfo));
+	resultRelInfo = resultRelInfos;
+	foreach(cell, rels)
+	{
+		Relation	rel = (Relation) lfirst(cell);
+
+		InitResultRelInfo(resultRelInfo,
+						  rel,
+						  0,			/* dummy rangetable index */
+						  CMD_DELETE,	/* don't need any index info */
+						  false);
+		resultRelInfo++;
+	}
+	estate->es_result_relations = resultRelInfos;
+	estate->es_num_result_relations = list_length(rels);
+
+	/*
+	 * Process all BEFORE STATEMENT TRUNCATE triggers before we begin
+	 * truncating (this is because one of them might throw an error).
+	 * Also, if we were to allow them to prevent statement execution,
+	 * that would need to be handled here.
+	 */
+	resultRelInfo = resultRelInfos;
+	foreach(cell, rels)
+	{
+		estate->es_result_relation_info = resultRelInfo;
+		ExecBSTruncateTriggers(estate, resultRelInfo);
+		resultRelInfo++;
+	}
+
 	/*
 	 * OK, truncate each table.
 	 */
@@ -637,6 +679,23 @@ ExecuteTruncate(TruncateStmt *stmt)
 		 */
 		reindex_relation(heap_relid, true);
 	}
+
+	/*
+	 * Process all AFTER STATEMENT TRUNCATE triggers.
+	 */
+	resultRelInfo = resultRelInfos;
+	foreach(cell, rels)
+	{
+		estate->es_result_relation_info = resultRelInfo;
+		ExecASTruncateTriggers(estate, resultRelInfo);
+		resultRelInfo++;
+	}
+
+	/* Handle queued AFTER triggers */
+	AfterTriggerEndQuery(estate);
+
+	/* We can clean up the EState now */
+	FreeExecutorState(estate);
 }
 
 /*
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 7dfe73aa068..9a7a0f81e73 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 1.230 2008/03/26 21:10:38 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.231 2008/03/28 00:21:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -179,6 +179,18 @@ CreateTrigger(CreateTrigStmt *stmt, Oid constraintOid)
 							 errmsg("multiple UPDATE events specified")));
 				TRIGGER_SETT_UPDATE(tgtype);
 				break;
+			case 't':
+				if (TRIGGER_FOR_TRUNCATE(tgtype))
+					ereport(ERROR,
+							(errcode(ERRCODE_SYNTAX_ERROR),
+							 errmsg("multiple TRUNCATE events specified")));
+				TRIGGER_SETT_TRUNCATE(tgtype);
+				/* Disallow ROW-level TRUNCATE triggers */
+				if (stmt->row)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("TRUNCATE FOR EACH ROW triggers are not supported")));
+				break;
 			default:
 				elog(ERROR, "unrecognized trigger event: %d",
 					 (int) stmt->actions[i]);
@@ -1299,6 +1311,15 @@ InsertTrigger(TriggerDesc *trigdesc, Trigger *trigger, int indx)
 		(*tp)[n[TRIGGER_EVENT_UPDATE]] = indx;
 		(n[TRIGGER_EVENT_UPDATE])++;
 	}
+
+	if (TRIGGER_FOR_TRUNCATE(trigger->tgtype))
+	{
+		tp = &(t[TRIGGER_EVENT_TRUNCATE]);
+		if (*tp == NULL)
+			*tp = (int *) palloc(trigdesc->numtriggers * sizeof(int));
+		(*tp)[n[TRIGGER_EVENT_TRUNCATE]] = indx;
+		(n[TRIGGER_EVENT_TRUNCATE])++;
+	}
 }
 
 /*
@@ -2030,6 +2051,75 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
 	}
 }
 
+void
+ExecBSTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
+{
+	TriggerDesc *trigdesc;
+	int			ntrigs;
+	int		   *tgindx;
+	int			i;
+	TriggerData LocTriggerData;
+
+	trigdesc = relinfo->ri_TrigDesc;
+
+	if (trigdesc == NULL)
+		return;
+
+	ntrigs = trigdesc->n_before_statement[TRIGGER_EVENT_TRUNCATE];
+	tgindx = trigdesc->tg_before_statement[TRIGGER_EVENT_TRUNCATE];
+
+	if (ntrigs == 0)
+		return;
+
+	LocTriggerData.type = T_TriggerData;
+	LocTriggerData.tg_event = TRIGGER_EVENT_TRUNCATE |
+		TRIGGER_EVENT_BEFORE;
+	LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
+	LocTriggerData.tg_trigtuple = NULL;
+	LocTriggerData.tg_newtuple = NULL;
+	LocTriggerData.tg_trigtuplebuf = InvalidBuffer;
+	LocTriggerData.tg_newtuplebuf = InvalidBuffer;
+	for (i = 0; i < ntrigs; i++)
+	{
+		Trigger    *trigger = &trigdesc->triggers[tgindx[i]];
+		HeapTuple	newtuple;
+
+		if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
+		{
+			if (trigger->tgenabled == TRIGGER_FIRES_ON_ORIGIN ||
+				trigger->tgenabled == TRIGGER_DISABLED)
+				continue;
+		}
+		else	/* ORIGIN or LOCAL role */
+		{
+			if (trigger->tgenabled == TRIGGER_FIRES_ON_REPLICA ||
+				trigger->tgenabled == TRIGGER_DISABLED)
+				continue;
+		}
+		LocTriggerData.tg_trigger = trigger;
+		newtuple = ExecCallTriggerFunc(&LocTriggerData,
+									   tgindx[i],
+									   relinfo->ri_TrigFunctions,
+									   relinfo->ri_TrigInstrument,
+									   GetPerTupleMemoryContext(estate));
+
+		if (newtuple)
+			ereport(ERROR,
+		 			(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+		 		  errmsg("BEFORE STATEMENT trigger cannot return a value")));
+	}
+}
+
+void
+ExecASTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
+{
+	TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
+
+	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_TRUNCATE] > 0)
+		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_TRUNCATE,
+							  false, NULL, NULL);
+}
+
 
 static HeapTuple
 GetTupleForTrigger(EState *estate, ResultRelInfo *relinfo,
@@ -3572,6 +3662,12 @@ AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
 		elog(ERROR, "AfterTriggerSaveEvent() called outside of transaction");
 
 	/*
+	 * event is used both as a bitmask and an array offset,
+	 * so make sure we don't walk off the edge of our arrays
+	 */
+	Assert(event >= 0 && event < TRIGGER_NUM_EVENT_CLASSES);
+
+	/*
 	 * Get the CTID's of OLD and NEW
 	 */
 	if (oldtup != NULL)
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 4f06aa12410..db69ebb1403 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.304 2008/03/26 21:10:38 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.305 2008/03/28 00:21:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -66,11 +66,6 @@ typedef struct evalPlanQual
 
 /* decls for local routines only used within this module */
 static void InitPlan(QueryDesc *queryDesc, int eflags);
-static void initResultRelInfo(ResultRelInfo *resultRelInfo,
-				  Relation resultRelationDesc,
-				  Index resultRelationIndex,
-				  CmdType operation,
-				  bool doInstrument);
 static void ExecEndPlan(PlanState *planstate, EState *estate);
 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
 			CmdType operation,
@@ -525,7 +520,7 @@ InitPlan(QueryDesc *queryDesc, int eflags)
 
 			resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 			resultRelation = heap_open(resultRelationOid, RowExclusiveLock);
-			initResultRelInfo(resultRelInfo,
+			InitResultRelInfo(resultRelInfo,
 							  resultRelation,
 							  resultRelationIndex,
 							  operation,
@@ -860,8 +855,8 @@ InitPlan(QueryDesc *queryDesc, int eflags)
 /*
  * Initialize ResultRelInfo data for one result relation
  */
-static void
-initResultRelInfo(ResultRelInfo *resultRelInfo,
+void
+InitResultRelInfo(ResultRelInfo *resultRelInfo,
 				  Relation resultRelationDesc,
 				  Index resultRelationIndex,
 				  CmdType operation,
@@ -997,11 +992,11 @@ ExecGetTriggerResultRel(EState *estate, Oid relid)
 	/*
 	 * Make the new entry in the right context.  Currently, we don't need any
 	 * index information in ResultRelInfos used only for triggers, so tell
-	 * initResultRelInfo it's a DELETE.
+	 * InitResultRelInfo it's a DELETE.
 	 */
 	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 	rInfo = makeNode(ResultRelInfo);
-	initResultRelInfo(rInfo,
+	InitResultRelInfo(rInfo,
 					  rel,
 					  0,		/* dummy rangetable index */
 					  CMD_DELETE,
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ac14c2f2c74..21fff239c70 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.610 2008/03/21 22:41:48 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.611 2008/03/28 00:21:55 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -2719,6 +2719,7 @@ TriggerOneEvent:
 			INSERT									{ $$ = 'i'; }
 			| DELETE_P								{ $$ = 'd'; }
 			| UPDATE								{ $$ = 'u'; }
+			| TRUNCATE								{ $$ = 't'; }
 		;
 
 TriggerForSpec:
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index b1cff88b397..26bda928fa6 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.271 2008/03/26 21:10:39 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.272 2008/03/28 00:21:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -499,6 +499,13 @@ pg_get_triggerdef(PG_FUNCTION_ARGS)
 		else
 			appendStringInfo(&buf, " UPDATE");
 	}
+	if (TRIGGER_FOR_TRUNCATE(trigrec->tgtype))
+	{
+		if (findx > 0)
+			appendStringInfo(&buf, " OR TRUNCATE");
+		else
+			appendStringInfo(&buf, " TRUNCATE");
+	}
 	appendStringInfo(&buf, " ON %s ",
 					 generate_relation_name(trigrec->tgrelid));
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 25e784cb5e9..acd23f02e81 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -12,7 +12,7 @@
  *	by PostgreSQL
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.485 2008/03/27 03:57:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.486 2008/03/28 00:21:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -9631,6 +9631,13 @@ dumpTrigger(Archive *fout, TriggerInfo *tginfo)
 		else
 			appendPQExpBuffer(query, " UPDATE");
 	}
+	if (TRIGGER_FOR_TRUNCATE(tginfo->tgtype))
+	{
+		if (findx > 0)
+			appendPQExpBuffer(query, " OR TRUNCATE");
+		else
+			appendPQExpBuffer(query, " TRUNCATE");
+	}
 	appendPQExpBuffer(query, " ON %s\n",
 					  fmtId(tbinfo->dobj.name));
 
diff --git a/src/include/catalog/pg_trigger.h b/src/include/catalog/pg_trigger.h
index 84d3f69ce53..f6e1675b05f 100644
--- a/src/include/catalog/pg_trigger.h
+++ b/src/include/catalog/pg_trigger.h
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_trigger.h,v 1.31 2008/03/27 03:57:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_trigger.h,v 1.32 2008/03/28 00:21:56 tgl Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -89,6 +89,7 @@ typedef FormData_pg_trigger *Form_pg_trigger;
 #define TRIGGER_TYPE_INSERT				(1 << 2)
 #define TRIGGER_TYPE_DELETE				(1 << 3)
 #define TRIGGER_TYPE_UPDATE				(1 << 4)
+#define TRIGGER_TYPE_TRUNCATE			(1 << 5)
 
 /* Macros for manipulating tgtype */
 #define TRIGGER_CLEAR_TYPE(type)		((type) = 0)
@@ -98,11 +99,13 @@ typedef FormData_pg_trigger *Form_pg_trigger;
 #define TRIGGER_SETT_INSERT(type)		((type) |= TRIGGER_TYPE_INSERT)
 #define TRIGGER_SETT_DELETE(type)		((type) |= TRIGGER_TYPE_DELETE)
 #define TRIGGER_SETT_UPDATE(type)		((type) |= TRIGGER_TYPE_UPDATE)
+#define TRIGGER_SETT_TRUNCATE(type)		((type) |= TRIGGER_TYPE_TRUNCATE)
 
 #define TRIGGER_FOR_ROW(type)			((type) & TRIGGER_TYPE_ROW)
 #define TRIGGER_FOR_BEFORE(type)		((type) & TRIGGER_TYPE_BEFORE)
 #define TRIGGER_FOR_INSERT(type)		((type) & TRIGGER_TYPE_INSERT)
 #define TRIGGER_FOR_DELETE(type)		((type) & TRIGGER_TYPE_DELETE)
 #define TRIGGER_FOR_UPDATE(type)		((type) & TRIGGER_TYPE_UPDATE)
+#define TRIGGER_FOR_TRUNCATE(type)		((type) & TRIGGER_TYPE_TRUNCATE)
 
 #endif   /* PG_TRIGGER_H */
diff --git a/src/include/commands/trigger.h b/src/include/commands/trigger.h
index 5e0dda4744d..174b6507d1a 100644
--- a/src/include/commands/trigger.h
+++ b/src/include/commands/trigger.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.66 2008/01/02 23:34:42 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.67 2008/03/28 00:21:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -38,11 +38,18 @@ typedef struct TriggerData
 	Buffer		tg_newtuplebuf;
 } TriggerData;
 
-/* TriggerEvent bit flags */
-
+/*
+ * TriggerEvent bit flags 
+ *
+ * Note that we assume different event types (INSERT/DELETE/UPDATE/TRUNCATE)
+ * can't be OR'd together in a single TriggerEvent.  This is unlike the
+ * situation for pg_trigger rows, so pg_trigger.tgtype uses a different
+ * representation!
+ */
 #define TRIGGER_EVENT_INSERT			0x00000000
 #define TRIGGER_EVENT_DELETE			0x00000001
 #define TRIGGER_EVENT_UPDATE			0x00000002
+#define TRIGGER_EVENT_TRUNCATE			0x00000003
 #define TRIGGER_EVENT_OPMASK			0x00000003
 #define TRIGGER_EVENT_ROW				0x00000004
 #define TRIGGER_EVENT_BEFORE			0x00000008
@@ -66,6 +73,10 @@ typedef struct TriggerData
 		(((TriggerEvent) (event) & TRIGGER_EVENT_OPMASK) == \
 												TRIGGER_EVENT_UPDATE)
 
+#define TRIGGER_FIRED_BY_TRUNCATE(event) \
+		(((TriggerEvent) (event) & TRIGGER_EVENT_OPMASK) == \
+												TRIGGER_EVENT_TRUNCATE)
+
 #define TRIGGER_FIRED_FOR_ROW(event)			\
 		((TriggerEvent) (event) & TRIGGER_EVENT_ROW)
 
@@ -140,6 +151,10 @@ extern void ExecARUpdateTriggers(EState *estate,
 					 ResultRelInfo *relinfo,
 					 ItemPointer tupleid,
 					 HeapTuple newtuple);
+extern void ExecBSTruncateTriggers(EState *estate,
+					 ResultRelInfo *relinfo);
+extern void ExecASTruncateTriggers(EState *estate,
+					 ResultRelInfo *relinfo);
 
 extern void AfterTriggerBeginXact(void);
 extern void AfterTriggerBeginQuery(void);
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 7dc8b8d63a8..2a920cebb9a 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/executor.h,v 1.146 2008/01/01 19:45:57 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/executor/executor.h,v 1.147 2008/03/28 00:21:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -138,6 +138,11 @@ extern TupleTableSlot *ExecutorRun(QueryDesc *queryDesc,
 			ScanDirection direction, long count);
 extern void ExecutorEnd(QueryDesc *queryDesc);
 extern void ExecutorRewind(QueryDesc *queryDesc);
+extern void InitResultRelInfo(ResultRelInfo *resultRelInfo,
+				  Relation resultRelationDesc,
+				  Index resultRelationIndex,
+				  CmdType operation,
+				  bool doInstrument);
 extern ResultRelInfo *ExecGetTriggerResultRel(EState *estate, Oid relid);
 extern bool ExecContextForcesOids(PlanState *planstate, bool *hasoids);
 extern void ExecConstraints(ResultRelInfo *resultRelInfo,
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 340b24a77f3..f7d46193de5 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.104 2008/01/01 19:45:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.105 2008/03/28 00:21:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -71,9 +71,10 @@ typedef struct TriggerDesc
 	/*
 	 * Index data to identify which triggers are which.  Since each trigger
 	 * can appear in more than one class, for each class we provide a list of
-	 * integer indexes into the triggers array.
+	 * integer indexes into the triggers array.  The class codes are defined
+	 * by TRIGGER_EVENT_xxx macros in commands/trigger.h.
 	 */
-#define TRIGGER_NUM_EVENT_CLASSES  3
+#define TRIGGER_NUM_EVENT_CLASSES  4
 
 	uint16		n_before_statement[TRIGGER_NUM_EVENT_CLASSES];
 	uint16		n_before_row[TRIGGER_NUM_EVENT_CLASSES];
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 9922a4a0edb..1bf95d96059 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -1,7 +1,7 @@
 /**********************************************************************
  * plperl.c - perl as a procedural language for PostgreSQL
  *
- *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.138 2008/03/25 22:42:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.139 2008/03/28 00:21:56 tgl Exp $
  *
  **********************************************************************/
 
@@ -689,6 +689,8 @@ plperl_trigger_build_args(FunctionCallInfo fcinfo)
 												   tupdesc));
 		}
 	}
+	else if (TRIGGER_FIRED_BY_TRUNCATE(tdata->tg_event))
+		event = "TRUNCATE";
 	else
 		event = "UNKNOWN";
 
@@ -1395,6 +1397,8 @@ plperl_trigger_handler(PG_FUNCTION_ARGS)
 			retval = (Datum) trigdata->tg_newtuple;
 		else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
 			retval = (Datum) trigdata->tg_trigtuple;
+		else if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
+			retval = (Datum) trigdata->tg_trigtuple;
 		else
 			retval = (Datum) 0; /* can this happen? */
 	}
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 592365cad88..931e17d26d8 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.206 2008/03/26 18:48:59 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.207 2008/03/28 00:21:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -538,8 +538,10 @@ plpgsql_exec_trigger(PLpgSQL_function *func,
 		var->value = CStringGetTextDatum("UPDATE");
 	else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
 		var->value = CStringGetTextDatum("DELETE");
+	else if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
+		var->value = CStringGetTextDatum("TRUNCATE");
 	else
-		elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, or UPDATE");
+		elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, UPDATE, or TRUNCATE");
 	var->isnull = false;
 	var->freeval = true;
 
diff --git a/src/pl/plpython/plpython.c b/src/pl/plpython/plpython.c
index 20177d62e1b..130eca4f71d 100644
--- a/src/pl/plpython/plpython.c
+++ b/src/pl/plpython/plpython.c
@@ -1,7 +1,7 @@
 /**********************************************************************
  * plpython.c - python as a procedural language for PostgreSQL
  *
- *	$PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.107 2008/03/25 22:42:45 tgl Exp $
+ *	$PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.108 2008/03/28 00:21:56 tgl Exp $
  *
  *********************************************************************
  */
@@ -714,6 +714,8 @@ PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure * proc, HeapTuple *
 				pltevent = PyString_FromString("DELETE");
 			else if (TRIGGER_FIRED_BY_UPDATE(tdata->tg_event))
 				pltevent = PyString_FromString("UPDATE");
+			else if (TRIGGER_FIRED_BY_TRUNCATE(tdata->tg_event))
+				pltevent = PyString_FromString("TRUNCATE");
 			else
 			{
 				elog(ERROR, "unrecognized OP tg_event: %u", tdata->tg_event);
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 508ec301bf8..5219a4127e0 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -2,7 +2,7 @@
  * pltcl.c		- PostgreSQL support for Tcl as
  *				  procedural language (PL)
  *
- *	  $PostgreSQL: pgsql/src/pl/tcl/pltcl.c,v 1.118 2008/03/25 22:42:46 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/tcl/pltcl.c,v 1.119 2008/03/28 00:21:56 tgl Exp $
  *
  **********************************************************************/
 
@@ -824,6 +824,8 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS)
 				Tcl_DStringAppendElement(&tcl_cmd, "DELETE");
 			else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
 				Tcl_DStringAppendElement(&tcl_cmd, "UPDATE");
+			else if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
+				Tcl_DStringAppendElement(&tcl_cmd, "TRUNCATE");
 			else
 				elog(ERROR, "unrecognized OP tg_event: %u", trigdata->tg_event);
 
diff --git a/src/test/regress/expected/truncate.out b/src/test/regress/expected/truncate.out
index 95aa3737954..ed6182c69f9 100644
--- a/src/test/regress/expected/truncate.out
+++ b/src/test/regress/expected/truncate.out
@@ -145,3 +145,81 @@ NOTICE:  drop cascades to constraint trunc_e_a_fkey on table trunc_e
 NOTICE:  drop cascades to constraint trunc_b_a_fkey on table trunc_b
 NOTICE:  drop cascades to constraint trunc_e_b_fkey on table trunc_e
 NOTICE:  drop cascades to constraint trunc_d_a_fkey on table trunc_d
+-- Test ON TRUNCATE triggers
+CREATE TABLE trunc_trigger_test (f1 int, f2 text, f3 text);
+CREATE TABLE trunc_trigger_log (tgop text, tglevel text, tgwhen text,
+        tgargv text, tgtable name, rowcount bigint);
+CREATE FUNCTION trunctrigger() RETURNS trigger as $$
+declare c bigint;
+begin
+    execute 'select count(*) from ' || quote_ident(tg_table_name) into c;
+    insert into trunc_trigger_log values
+      (TG_OP, TG_LEVEL, TG_WHEN, TG_ARGV[0], tg_table_name, c);
+    return null;
+end;
+$$ LANGUAGE plpgsql;
+-- basic before trigger
+INSERT INTO trunc_trigger_test VALUES(1, 'foo', 'bar'), (2, 'baz', 'quux');
+CREATE TRIGGER t
+BEFORE TRUNCATE ON trunc_trigger_test
+FOR EACH STATEMENT 
+EXECUTE PROCEDURE trunctrigger('before trigger truncate');
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+ Row count in test table 
+-------------------------
+                       2
+(1 row)
+
+SELECT * FROM trunc_trigger_log;
+ tgop | tglevel | tgwhen | tgargv | tgtable | rowcount 
+------+---------+--------+--------+---------+----------
+(0 rows)
+
+TRUNCATE trunc_trigger_test;
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+ Row count in test table 
+-------------------------
+                       0
+(1 row)
+
+SELECT * FROM trunc_trigger_log;
+   tgop   |  tglevel  | tgwhen |         tgargv          |      tgtable       | rowcount 
+----------+-----------+--------+-------------------------+--------------------+----------
+ TRUNCATE | STATEMENT | BEFORE | before trigger truncate | trunc_trigger_test |        2
+(1 row)
+
+DROP TRIGGER t ON trunc_trigger_test;
+truncate trunc_trigger_log;
+-- same test with an after trigger
+INSERT INTO trunc_trigger_test VALUES(1, 'foo', 'bar'), (2, 'baz', 'quux');
+CREATE TRIGGER tt
+AFTER TRUNCATE ON trunc_trigger_test
+FOR EACH STATEMENT 
+EXECUTE PROCEDURE trunctrigger('after trigger truncate');
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+ Row count in test table 
+-------------------------
+                       2
+(1 row)
+
+SELECT * FROM trunc_trigger_log;
+ tgop | tglevel | tgwhen | tgargv | tgtable | rowcount 
+------+---------+--------+--------+---------+----------
+(0 rows)
+
+TRUNCATE trunc_trigger_test;
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+ Row count in test table 
+-------------------------
+                       0
+(1 row)
+
+SELECT * FROM trunc_trigger_log;
+   tgop   |  tglevel  | tgwhen |         tgargv         |      tgtable       | rowcount 
+----------+-----------+--------+------------------------+--------------------+----------
+ TRUNCATE | STATEMENT | AFTER  | after trigger truncate | trunc_trigger_test |        0
+(1 row)
+
+DROP TABLE trunc_trigger_test;
+DROP TABLE trunc_trigger_log;
+DROP FUNCTION trunctrigger();
diff --git a/src/test/regress/sql/truncate.sql b/src/test/regress/sql/truncate.sql
index 9f8420b1844..e60349e2073 100644
--- a/src/test/regress/sql/truncate.sql
+++ b/src/test/regress/sql/truncate.sql
@@ -77,3 +77,56 @@ SELECT * FROM truncate_a
 SELECT * FROM trunc_e;
 
 DROP TABLE truncate_a,trunc_c,trunc_b,trunc_d,trunc_e CASCADE;
+
+-- Test ON TRUNCATE triggers
+
+CREATE TABLE trunc_trigger_test (f1 int, f2 text, f3 text);
+CREATE TABLE trunc_trigger_log (tgop text, tglevel text, tgwhen text,
+        tgargv text, tgtable name, rowcount bigint);
+
+CREATE FUNCTION trunctrigger() RETURNS trigger as $$
+declare c bigint;
+begin
+    execute 'select count(*) from ' || quote_ident(tg_table_name) into c;
+    insert into trunc_trigger_log values
+      (TG_OP, TG_LEVEL, TG_WHEN, TG_ARGV[0], tg_table_name, c);
+    return null;
+end;
+$$ LANGUAGE plpgsql;
+
+-- basic before trigger
+INSERT INTO trunc_trigger_test VALUES(1, 'foo', 'bar'), (2, 'baz', 'quux');
+
+CREATE TRIGGER t
+BEFORE TRUNCATE ON trunc_trigger_test
+FOR EACH STATEMENT 
+EXECUTE PROCEDURE trunctrigger('before trigger truncate');
+
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+SELECT * FROM trunc_trigger_log;
+TRUNCATE trunc_trigger_test;
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+SELECT * FROM trunc_trigger_log;
+
+DROP TRIGGER t ON trunc_trigger_test;
+
+truncate trunc_trigger_log;
+
+-- same test with an after trigger
+INSERT INTO trunc_trigger_test VALUES(1, 'foo', 'bar'), (2, 'baz', 'quux');
+
+CREATE TRIGGER tt
+AFTER TRUNCATE ON trunc_trigger_test
+FOR EACH STATEMENT 
+EXECUTE PROCEDURE trunctrigger('after trigger truncate');
+
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+SELECT * FROM trunc_trigger_log;
+TRUNCATE trunc_trigger_test;
+SELECT count(*) as "Row count in test table" FROM trunc_trigger_test;
+SELECT * FROM trunc_trigger_log;
+
+DROP TABLE trunc_trigger_test;
+DROP TABLE trunc_trigger_log;
+
+DROP FUNCTION trunctrigger();