Support SQL-compliant triggers on columns, ie fire only if certain columns

are named in the UPDATE's SET list. Note: the schema of pg_trigger has not actually changed; we've just started to use a column that was there all along. catversion bumped anyway so that this commit is included in the history of potentially interesting changes to system catalog contents. Itagaki Takahiro
2025-11-29 23:43:17 +03:00 · 2009-10-14 22:14:25 +00:00
parent be922e8555
commit b2734a0d79
17 changed files with 433 additions and 183 deletions
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -8,7 +8,7 @@
 *
 *
 * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.322 2009/10/05 19:24:35 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.323 2009/10/14 22:14:21 tgl Exp $
 *
 *
 * INTERFACE ROUTINES
@@ -792,6 +792,7 @@ index_create(Oid heapRelationId,
 				trigger->before = false;
 				trigger->row = true;
 				trigger->events = TRIGGER_TYPE_INSERT | TRIGGER_TYPE_UPDATE;
+				trigger->columns = NIL;
 				trigger->isconstraint = true;
 				trigger->deferrable = true;
 				trigger->initdeferred = initdeferred;
--- 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 1.303 2009/10/13 00:53:07 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.304 2009/10/14 22:14:21 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
@@ -5441,6 +5441,7 @@ CreateFKCheckTrigger(RangeVar *myRel, Constraint *fkconstraint,
 		fk_trigger->events = TRIGGER_TYPE_UPDATE;
 	}

+	fk_trigger->columns = NIL;
 	fk_trigger->isconstraint = true;
 	fk_trigger->deferrable = fkconstraint->deferrable;
 	fk_trigger->initdeferred = fkconstraint->initdeferred;
@@ -5491,6 +5492,7 @@ createForeignKeyTriggers(Relation rel, Constraint *fkconstraint,
 	fk_trigger->before = false;
 	fk_trigger->row = true;
 	fk_trigger->events = TRIGGER_TYPE_DELETE;
+	fk_trigger->columns = NIL;
 	fk_trigger->isconstraint = true;
 	fk_trigger->constrrel = myRel;
 	switch (fkconstraint->fk_del_action)
@@ -5543,6 +5545,7 @@ createForeignKeyTriggers(Relation rel, Constraint *fkconstraint,
 	fk_trigger->before = false;
 	fk_trigger->row = true;
 	fk_trigger->events = TRIGGER_TYPE_UPDATE;
+	fk_trigger->columns = NIL;
 	fk_trigger->isconstraint = true;
 	fk_trigger->constrrel = myRel;
 	switch (fkconstraint->fk_upd_action)
--- 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 1.253 2009/10/10 01:43:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.254 2009/10/14 22:14:21 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
@@ -30,8 +30,11 @@
 #include "executor/executor.h"
 #include "executor/instrument.h"
 #include "miscadmin.h"
+#include "nodes/bitmapset.h"
 #include "nodes/makefuncs.h"
 #include "parser/parse_func.h"
+#include "parser/parse_relation.h"
+#include "parser/parsetree.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
 #include "tcop/utility.h"
@@ -51,6 +54,9 @@
 int			SessionReplicationRole = SESSION_REPLICATION_ROLE_ORIGIN;


+#define GetModifiedColumns(relinfo, estate) \
+	(rt_fetch((relinfo)->ri_RangeTableIndex, (estate)->es_range_table)->modifiedCols)
+
 /* Local function prototypes */
 static void ConvertTriggerToFK(CreateTrigStmt *stmt, Oid funcoid);
 static void InsertTrigger(TriggerDesc *trigdesc, Trigger *trigger, int indx);
@@ -59,6 +65,8 @@ static HeapTuple GetTupleForTrigger(EState *estate,
 				   ResultRelInfo *relinfo,
 				   ItemPointer tid,
 				   TupleTableSlot **newSlot);
+static bool TriggerEnabled(Trigger *trigger, TriggerEvent event,
+						   Bitmapset *modifiedCols);
 static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
 					int tgindx,
 					FmgrInfo *finfo,
@@ -66,7 +74,7 @@ static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
 					MemoryContext per_tuple_context);
 static void AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event,
 					  bool row_trigger, HeapTuple oldtup, HeapTuple newtup,
-					  List *recheckIndexes);
+					  List *recheckIndexes, Bitmapset *modifiedCols);


 /*
@@ -98,6 +106,8 @@ CreateTrigger(CreateTrigStmt *stmt,
 			  bool checkPermissions)
 {
 	int16		tgtype;
+	int			ncolumns;
+	int2       *columns;
 	int2vector *tgattr;
 	Datum		values[Natts_pg_trigger];
 	bool		nulls[Natts_pg_trigger];
@@ -337,8 +347,44 @@ CreateTrigger(CreateTrigStmt *stmt,
 														CStringGetDatum(""));
 	}

-	/* tgattr is currently always a zero-length array */
-	tgattr = buildint2vector(NULL, 0);
+	/* build column number array if it's a column-specific trigger */
+	ncolumns = list_length(stmt->columns);
+	if (ncolumns == 0)
+		columns = NULL;
+	else
+	{
+		ListCell   *cell;
+		int			i = 0;
+
+		columns = (int2 *) palloc(ncolumns * sizeof(int2));
+		foreach(cell, stmt->columns)
+		{
+			char   *name = strVal(lfirst(cell));
+			int2	attnum;
+			int		j;
+
+			/* Lookup column name.  System columns are not allowed */
+			attnum = attnameAttNum(rel, name, false);
+			if (attnum == InvalidAttrNumber)
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_COLUMN),
+						 errmsg("column \"%s\" of relation \"%s\" does not exist",
+								name, RelationGetRelationName(rel))));
+
+			/* Check for duplicates */
+			for (j = i - 1; j >= 0; j--)
+			{
+				if (columns[j] == attnum)
+					ereport(ERROR,
+							(errcode(ERRCODE_DUPLICATE_COLUMN),
+							 errmsg("column \"%s\" specified more than once",
+									name)));
+			}
+
+			columns[i++] = attnum;
+		}
+	}
+	tgattr = buildint2vector(columns, ncolumns);
 	values[Anum_pg_trigger_tgattr - 1] = PointerGetDatum(tgattr);

 	tuple = heap_form_tuple(tgrel->rd_att, values, nulls);
@@ -358,6 +404,7 @@ CreateTrigger(CreateTrigStmt *stmt,

 	pfree(DatumGetPointer(values[Anum_pg_trigger_tgname - 1]));
 	pfree(DatumGetPointer(values[Anum_pg_trigger_tgargs - 1]));
+	pfree(DatumGetPointer(values[Anum_pg_trigger_tgattr - 1]));

 	/*
 	 * Update relation's pg_class entry.  Crucial side-effect: other backends
@@ -434,6 +481,20 @@ CreateTrigger(CreateTrigStmt *stmt,
 		Assert(!OidIsValid(indexOid));
 	}

+	/* If column-specific trigger, add normal dependencies on columns */
+	if (columns != NULL)
+	{
+		int		i;
+
+		referenced.classId = RelationRelationId;
+		referenced.objectId = RelationGetRelid(rel);
+		for (i = 0; i < ncolumns; i++)
+		{
+			referenced.objectSubId = columns[i];
+			recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+		}
+	}
+
 	/* Keep lock on target rel until end of xact */
 	heap_close(rel, NoLock);

@@ -1626,18 +1687,9 @@ ExecBSInsertTriggers(EState *estate, ResultRelInfo *relinfo)
 		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;
-		}
+		if (!TriggerEnabled(trigger, LocTriggerData.tg_event, NULL))
+			continue;
+
 		LocTriggerData.tg_trigger = trigger;
 		newtuple = ExecCallTriggerFunc(&LocTriggerData,
 									   tgindx[i],
@@ -1659,7 +1711,7 @@ ExecASInsertTriggers(EState *estate, ResultRelInfo *relinfo)

 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_INSERT] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
-							  false, NULL, NULL, NIL);
+							  false, NULL, NULL, NIL, NULL);
 }

 HeapTuple
@@ -1685,18 +1737,9 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 	{
 		Trigger    *trigger = &trigdesc->triggers[tgindx[i]];

-		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;
-		}
+		if (!TriggerEnabled(trigger, LocTriggerData.tg_event, NULL))
+			continue;
+
 		LocTriggerData.tg_trigtuple = oldtuple = newtuple;
 		LocTriggerData.tg_trigtuplebuf = InvalidBuffer;
 		LocTriggerData.tg_trigger = trigger;
@@ -1721,7 +1764,7 @@ ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,

 	if (trigdesc && trigdesc->n_after_row[TRIGGER_EVENT_INSERT] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
-							  true, NULL, trigtuple, recheckIndexes);
+							  true, NULL, trigtuple, recheckIndexes, NULL);
 }

 void
@@ -1757,18 +1800,9 @@ ExecBSDeleteTriggers(EState *estate, ResultRelInfo *relinfo)
 		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;
-		}
+		if (!TriggerEnabled(trigger, LocTriggerData.tg_event, NULL))
+			continue;
+
 		LocTriggerData.tg_trigger = trigger;
 		newtuple = ExecCallTriggerFunc(&LocTriggerData,
 									   tgindx[i],
@@ -1790,7 +1824,7 @@ ExecASDeleteTriggers(EState *estate, ResultRelInfo *relinfo)

 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_DELETE] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
-							  false, NULL, NULL, NIL);
+							  false, NULL, NULL, NIL, NULL);
 }

 bool
@@ -1824,18 +1858,9 @@ ExecBRDeleteTriggers(EState *estate, PlanState *subplanstate,
 	{
 		Trigger    *trigger = &trigdesc->triggers[tgindx[i]];

-		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;
-		}
+		if (!TriggerEnabled(trigger, LocTriggerData.tg_event, NULL))
+			continue;
+
 		LocTriggerData.tg_trigtuple = trigtuple;
 		LocTriggerData.tg_trigtuplebuf = InvalidBuffer;
 		LocTriggerData.tg_trigger = trigger;
@@ -1869,7 +1894,7 @@ ExecARDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
 												   tupleid, NULL);

 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
-							  true, trigtuple, NULL, NIL);
+							  true, trigtuple, NULL, NIL, NULL);
 		heap_freetuple(trigtuple);
 	}
 }
@@ -1882,6 +1907,7 @@ ExecBSUpdateTriggers(EState *estate, ResultRelInfo *relinfo)
 	int		   *tgindx;
 	int			i;
 	TriggerData LocTriggerData;
+	Bitmapset   *modifiedCols;

 	trigdesc = relinfo->ri_TrigDesc;

@@ -1894,6 +1920,8 @@ ExecBSUpdateTriggers(EState *estate, ResultRelInfo *relinfo)
 	if (ntrigs == 0)
 		return;

+	modifiedCols = GetModifiedColumns(relinfo, estate);
+
 	LocTriggerData.type = T_TriggerData;
 	LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE |
 		TRIGGER_EVENT_BEFORE;
@@ -1907,18 +1935,9 @@ ExecBSUpdateTriggers(EState *estate, ResultRelInfo *relinfo)
 		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;
-		}
+		if (!TriggerEnabled(trigger, LocTriggerData.tg_event, modifiedCols))
+			continue;
+
 		LocTriggerData.tg_trigger = trigger;
 		newtuple = ExecCallTriggerFunc(&LocTriggerData,
 									   tgindx[i],
@@ -1940,7 +1959,8 @@ ExecASUpdateTriggers(EState *estate, ResultRelInfo *relinfo)

 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_UPDATE] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
-							  false, NULL, NULL, NIL);
+							  false, NULL, NULL, NIL,
+							  GetModifiedColumns(relinfo, estate));
 }

 HeapTuple
@@ -1957,6 +1977,7 @@ ExecBRUpdateTriggers(EState *estate, PlanState *subplanstate,
 	HeapTuple	intuple = newtuple;
 	TupleTableSlot *newSlot;
 	int			i;
+	Bitmapset   *modifiedCols;

 	trigtuple = GetTupleForTrigger(estate, subplanstate, relinfo, tupleid,
 								   &newSlot);
@@ -1971,6 +1992,8 @@ ExecBRUpdateTriggers(EState *estate, PlanState *subplanstate,
 	if (newSlot != NULL)
 		intuple = newtuple = ExecRemoveJunk(relinfo->ri_junkFilter, newSlot);

+	modifiedCols = GetModifiedColumns(relinfo, estate);
+
 	LocTriggerData.type = T_TriggerData;
 	LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE |
 		TRIGGER_EVENT_ROW |
@@ -1980,18 +2003,9 @@ ExecBRUpdateTriggers(EState *estate, PlanState *subplanstate,
 	{
 		Trigger    *trigger = &trigdesc->triggers[tgindx[i]];

-		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;
-		}
+		if (!TriggerEnabled(trigger, LocTriggerData.tg_event, modifiedCols))
+			continue;
+
 		LocTriggerData.tg_trigtuple = trigtuple;
 		LocTriggerData.tg_newtuple = oldtuple = newtuple;
 		LocTriggerData.tg_trigtuplebuf = InvalidBuffer;
@@ -2024,7 +2038,8 @@ ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
 												   tupleid, NULL);

 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
-							  true, trigtuple, newtuple, recheckIndexes);
+							  true, trigtuple, newtuple, recheckIndexes,
+							  GetModifiedColumns(relinfo, estate));
 		heap_freetuple(trigtuple);
 	}
 }
@@ -2062,18 +2077,9 @@ ExecBSTruncateTriggers(EState *estate, ResultRelInfo *relinfo)
 		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;
-		}
+		if (!TriggerEnabled(trigger, LocTriggerData.tg_event, NULL))
+			continue;
+
 		LocTriggerData.tg_trigger = trigger;
 		newtuple = ExecCallTriggerFunc(&LocTriggerData,
 									   tgindx[i],
@@ -2095,7 +2101,7 @@ ExecASTruncateTriggers(EState *estate, ResultRelInfo *relinfo)

 	if (trigdesc && trigdesc->n_after_statement[TRIGGER_EVENT_TRUNCATE] > 0)
 		AfterTriggerSaveEvent(relinfo, TRIGGER_EVENT_TRUNCATE,
-							  false, NULL, NULL, NIL);
+							  false, NULL, NULL, NIL, NULL);
 }


@@ -2201,6 +2207,52 @@ ltrmark:;
 	return result;
 }

+/*
+ * Is trigger enabled to fire?
+ */
+static bool
+TriggerEnabled(Trigger *trigger, TriggerEvent event, Bitmapset *modifiedCols)
+{
+	/* Check replication-role-dependent enable state */
+	if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
+	{
+		if (trigger->tgenabled == TRIGGER_FIRES_ON_ORIGIN ||
+			trigger->tgenabled == TRIGGER_DISABLED)
+			return false;
+	}
+	else	/* ORIGIN or LOCAL role */
+	{
+		if (trigger->tgenabled == TRIGGER_FIRES_ON_REPLICA ||
+			trigger->tgenabled == TRIGGER_DISABLED)
+			return false;
+	}
+
+	/*
+	 * Check for column-specific trigger (only possible for UPDATE, and in
+	 * fact we *must* ignore tgattr for other event types)
+	 */
+	if (trigger->tgnattr > 0 && TRIGGER_FIRED_BY_UPDATE(event))
+	{
+		int			i;
+		bool		modified;
+
+		modified = false;
+		for (i = 0; i < trigger->tgnattr; i++)
+		{
+			if (bms_is_member(trigger->tgattr[i] - FirstLowInvalidHeapAttributeNumber,
+							  modifiedCols))
+			{
+				modified = true;
+				break;
+			}
+		}
+		if (!modified)
+			return false;
+	}
+
+	return true;
+}
+

 /* ----------
 * After-trigger stuff
@@ -3825,7 +3877,7 @@ AfterTriggerPendingOnRel(Oid relid)
 static void
 AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
 					  HeapTuple oldtup, HeapTuple newtup,
-					  List *recheckIndexes)
+					  List *recheckIndexes, Bitmapset *modifiedCols)
 {
 	Relation	rel = relinfo->ri_RelationDesc;
 	TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
@@ -3927,26 +3979,15 @@ AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
 	{
 		Trigger    *trigger = &trigdesc->triggers[tgindx[i]];

-		/* Ignore disabled triggers */
-		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;
-		}
+		if (!TriggerEnabled(trigger, event, modifiedCols))
+			continue;

 		/*
 		 * If this is an UPDATE of a PK table or FK table that does not change
 		 * the PK or FK respectively, we can skip queuing the event: there is
 		 * no need to fire the trigger.
 		 */
-		if ((event & TRIGGER_EVENT_OPMASK) == TRIGGER_EVENT_UPDATE)
+		if (TRIGGER_FIRED_BY_UPDATE(event))
 		{
 			switch (RI_FKey_trigger_type(trigger->tgfoid))
 			{
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -15,7 +15,7 @@
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.447 2009/10/13 00:53:08 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.448 2009/10/14 22:14:21 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
@@ -3160,6 +3160,7 @@ _copyCreateTrigStmt(CreateTrigStmt *from)
 	COPY_SCALAR_FIELD(before);
 	COPY_SCALAR_FIELD(row);
 	COPY_SCALAR_FIELD(events);
+	COPY_NODE_FIELD(columns);
 	COPY_SCALAR_FIELD(isconstraint);
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -22,7 +22,7 @@
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.369 2009/10/13 00:53:08 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.370 2009/10/14 22:14:21 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
@@ -1671,6 +1671,7 @@ _equalCreateTrigStmt(CreateTrigStmt *a, CreateTrigStmt *b)
 	COMPARE_SCALAR_FIELD(before);
 	COMPARE_SCALAR_FIELD(row);
 	COMPARE_SCALAR_FIELD(events);
+	COMPARE_NODE_FIELD(columns);
 	COMPARE_SCALAR_FIELD(isconstraint);
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -9,7 +9,7 @@
 *
 *
 * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.152 2009/10/12 18:10:48 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.153 2009/10/14 22:14:22 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
@@ -193,7 +193,8 @@ set_plan_references(PlannerGlobal *glob, Plan *plan,
 	 * needed by the executor; this reduces the storage space and copying cost
 	 * for cached plans.  We keep only the alias and eref Alias fields, which
 	 * are needed by EXPLAIN, and the selectedCols and modifiedCols bitmaps,
-	 * which are needed for executor-startup permissions checking.
+	 * which are needed for executor-startup permissions checking and for
+	 * trigger event checking.
 	 */
 	foreach(lc, rtable)
 	{
--- 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 2.685 2009/10/12 23:41:43 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.686 2009/10/14 22:14:22 tgl Exp $
 *
 * HISTORY
 *	  AUTHOR			DATE			MAJOR EVENT
@@ -251,7 +251,7 @@ static TypeName *TableFuncTypeName(List *columns);

 %type <boolean> TriggerActionTime TriggerForSpec opt_trusted opt_restart_seqs

-%type <ival>	TriggerEvents TriggerOneEvent
+%type <list>	TriggerEvents TriggerOneEvent
 %type <value>	TriggerFuncArg

 %type <str>		relation_name copy_file_name
@@ -3240,7 +3240,8 @@ CreateTrigStmt:
 					n->args = $13;
 					n->before = $4;
 					n->row = $8;
-					n->events = $5;
+					n->events = intVal(linitial($5));
+					n->columns = (List *) lsecond($5);
 					n->isconstraint  = FALSE;
 					n->deferrable	 = FALSE;
 					n->initdeferred  = FALSE;
@@ -3260,7 +3261,8 @@ CreateTrigStmt:
 					n->args = $18;
 					n->before = FALSE;
 					n->row = TRUE;
-					n->events = $6;
+					n->events = intVal(linitial($6));
+					n->columns = (List *) lsecond($6);
 					n->isconstraint  = TRUE;
 					n->deferrable = ($10 & 1) != 0;
 					n->initdeferred = ($10 & 2) != 0;
@@ -3279,17 +3281,36 @@ TriggerEvents:
 				{ $$ = $1; }
 			| TriggerEvents OR TriggerOneEvent
 				{
-					if ($1 & $3)
+					int		events1 = intVal(linitial($1));
+					int		events2 = intVal(linitial($3));
+					List   *columns1 = (List *) lsecond($1);
+					List   *columns2 = (List *) lsecond($3);
+
+					if (events1 & events2)
 						parser_yyerror("duplicate trigger events specified");
-					$$ = $1 | $3;
+					/*
+					 * concat'ing the columns lists loses information about
+					 * which columns went with which event, but so long as
+					 * only UPDATE carries columns and we disallow multiple
+					 * UPDATE items, it doesn't matter.  Command execution
+					 * should just ignore the columns for non-UPDATE events.
+					 */
+					$$ = list_make2(makeInteger(events1 | events2),
+									list_concat(columns1, columns2));
 				}
 		;

 TriggerOneEvent:
-			INSERT								{ $$ = TRIGGER_TYPE_INSERT; }
-			| DELETE_P							{ $$ = TRIGGER_TYPE_DELETE; }
-			| UPDATE							{ $$ = TRIGGER_TYPE_UPDATE; }
-			| TRUNCATE							{ $$ = TRIGGER_TYPE_TRUNCATE; }
+			INSERT
+				{ $$ = list_make2(makeInteger(TRIGGER_TYPE_INSERT), NIL); }
+			| DELETE_P
+				{ $$ = list_make2(makeInteger(TRIGGER_TYPE_DELETE), NIL); }
+			| UPDATE
+				{ $$ = list_make2(makeInteger(TRIGGER_TYPE_UPDATE), NIL); }
+			| UPDATE OF columnList
+				{ $$ = list_make2(makeInteger(TRIGGER_TYPE_UPDATE), $3); }
+			| TRUNCATE
+				{ $$ = list_make2(makeInteger(TRIGGER_TYPE_TRUNCATE), NIL); }
 		;

 TriggerForSpec:
--- 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 1.309 2009/10/10 01:43:49 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.310 2009/10/14 22:14:23 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
@@ -543,6 +543,23 @@ pg_get_triggerdef_worker(Oid trigid, bool pretty)
 			appendStringInfo(&buf, " OR UPDATE");
 		else
 			appendStringInfo(&buf, " UPDATE");
+		/* tgattr is first var-width field, so OK to access directly */
+		if (trigrec->tgattr.dim1 > 0)
+		{
+			int		i;
+
+			appendStringInfoString(&buf, " OF ");
+			for (i = 0; i < trigrec->tgattr.dim1; i++)
+			{
+				char   *attname;
+
+				if (i > 0)
+					appendStringInfoString(&buf, ", ");
+				attname = get_relid_attribute_name(trigrec->tgrelid,
+												   trigrec->tgattr.values[i]);
+				appendStringInfoString(&buf, quote_identifier(attname));
+			}
+		}
 	}
 	if (TRIGGER_FOR_TRUNCATE(trigrec->tgtype))
 	{