Syntax support and documentation for event triggers.

They don't actually do anything yet; that will get fixed in a
follow-on commit.  But this gets the basic infrastructure in place,
including CREATE/ALTER/DROP EVENT TRIGGER; support for COMMENT,
SECURITY LABEL, and ALTER EXTENSION .. ADD/DROP EVENT TRIGGER;
pg_dump and psql support; and documentation for the anticipated
initial feature set.

Dimitri Fontaine, with review and a bunch of additional hacking by me.
Thom Brown extensively reviewed earlier versions of this patch set,
but there's not a whole lot of that code left in this commit, as it
turns out.

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201207111
+#define CATALOG_VERSION_NO	201207181
 
 #endif

src/include/catalog/dependency.h

@@ -146,6 +146,7 @@ typedef enum ObjectClass
 	OCLASS_USER_MAPPING,		/* pg_user_mapping */
 	OCLASS_DEFACL,				/* pg_default_acl */
 	OCLASS_EXTENSION,			/* pg_extension */
+	OCLASS_EVENT_TRIGGER,		/* pg_event_trigger */
 	MAX_OCLASS					/* MUST BE LAST */
 } ObjectClass;
 

src/include/catalog/indexing.h

@@ -234,6 +234,11 @@ DECLARE_UNIQUE_INDEX(pg_trigger_tgrelid_tgname_index, 2701, on pg_trigger using
 DECLARE_UNIQUE_INDEX(pg_trigger_oid_index, 2702, on pg_trigger using btree(oid oid_ops));
 #define TriggerOidIndexId  2702
 
+DECLARE_UNIQUE_INDEX(pg_event_trigger_evtname_index, 3467, on pg_event_trigger using btree(evtname name_ops));
+#define EventTriggerNameIndexId  3467
+DECLARE_UNIQUE_INDEX(pg_event_trigger_oid_index, 3468, on pg_event_trigger using btree(oid oid_ops));
+#define EventTriggerOidIndexId  3468
+
 DECLARE_UNIQUE_INDEX(pg_ts_config_cfgname_index, 3608, on pg_ts_config using btree(cfgname name_ops, cfgnamespace oid_ops));
 #define TSConfigNameNspIndexId	3608
 DECLARE_UNIQUE_INDEX(pg_ts_config_oid_index, 3712, on pg_ts_config using btree(oid oid_ops));

src/include/catalog/pg_event_trigger.h

@@ -0,0 +1,63 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_event_trigger.h
+ *	  definition of the system "event trigger" relation (pg_event_trigger)
+ *	  along with the relation's initial contents.
+ *
+ *
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/catalog/pg_event_trigger.h
+ *
+ * NOTES
+ *	  the genbki.pl script reads this file and generates .bki
+ *	  information from the DATA() statements.
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_EVENT_TRIGGER_H
+#define PG_EVENT_TRIGGER_H
+
+#include "catalog/genbki.h"
+
+/* ----------------
+ *		pg_event_trigger definition.	cpp turns this into
+ *		typedef struct FormData_pg_event_trigger
+ * ----------------
+ */
+#define EventTriggerRelationId  3466
+
+CATALOG(pg_event_trigger,3466)
+{
+	NameData	evtname;		/* trigger's name */
+	NameData	evtevent;		/* trigger's event */
+	Oid			evtowner;		/* trigger's owner */
+	Oid			evtfoid;		/* OID of function to be called */
+	char		evtenabled;		/* trigger's firing configuration WRT
+								 * session_replication_role */
+#ifdef CATALOG_VARLEN
+	text        evttags[1];		/* command TAGs this event trigger targets */
+#endif
+} FormData_pg_event_trigger;
+
+/* ----------------
+ *		Form_pg_event_trigger corresponds to a pointer to a tuple with
+ *		the format of pg_event_trigger relation.
+ * ----------------
+ */
+typedef FormData_pg_event_trigger *Form_pg_event_trigger;
+
+/* ----------------
+ *		compiler constants for pg_event_trigger
+ * ----------------
+ */
+#define Natts_pg_event_trigger					6
+#define Anum_pg_event_trigger_evtname			1
+#define Anum_pg_event_trigger_evtevent			2
+#define Anum_pg_event_trigger_evtowner			3
+#define Anum_pg_event_trigger_evtfoid			4
+#define Anum_pg_event_trigger_evtenabled		5
+#define Anum_pg_event_trigger_evttags			6
+
+#endif   /* PG_EVENT_TRIGGER_H */

src/include/catalog/pg_proc.h

@@ -3460,6 +3460,10 @@ DATA(insert OID = 2300 (  trigger_in		PGNSP PGUID 12 1 0 0 0 f f f f f f i 1 0 2
 DESCR("I/O");
 DATA(insert OID = 2301 (  trigger_out		PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 2275 "2279" _null_ _null_ _null_ _null_ trigger_out _null_ _null_ _null_ ));
 DESCR("I/O");
+DATA(insert OID = 3594 (  event_trigger_in	PGNSP PGUID 12 1 0 0 0 f f f f f f i 1 0 3838 "2275" _null_ _null_ _null_ _null_ event_trigger_in _null_ _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3595 (  event_trigger_out	PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 2275 "3838" _null_ _null_ _null_ _null_ event_trigger_out _null_ _null_ _null_ ));
+DESCR("I/O");
 DATA(insert OID = 2302 (  language_handler_in	PGNSP PGUID 12 1 0 0 0 f f f f f f i 1 0 2280 "2275" _null_ _null_ _null_ _null_ language_handler_in _null_ _null_ _null_ ));
 DESCR("I/O");
 DATA(insert OID = 2303 (  language_handler_out	PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 2275 "2280" _null_ _null_ _null_ _null_ language_handler_out _null_ _null_ _null_ ));

src/include/catalog/pg_type.h

@@ -650,6 +650,8 @@ DATA(insert OID = 2278 ( void			PGNSP PGUID  4 t p P f t \054 0 0 0 void_in void
 #define VOIDOID			2278
 DATA(insert OID = 2279 ( trigger		PGNSP PGUID  4 t p P f t \054 0 0 0 trigger_in trigger_out - - - - - i p f 0 -1 0 0 _null_ _null_ _null_ ));
 #define TRIGGEROID		2279
+DATA(insert OID = 3838 ( event_trigger		PGNSP PGUID  4 t p P f t \054 0 0 0 event_trigger_in event_trigger_out - - - - - i p f 0 -1 0 0 _null_ _null_ _null_ ));
+#define EVTTRIGGEROID		3838
 DATA(insert OID = 2280 ( language_handler	PGNSP PGUID  4 t p P f t \054 0 0 0 language_handler_in language_handler_out - - - - - i p f 0 -1 0 0 _null_ _null_ _null_ ));
 #define LANGUAGE_HANDLEROID		2280
 DATA(insert OID = 2281 ( internal		PGNSP PGUID  SIZEOF_POINTER t p P f t \054 0 0 0 internal_in internal_out - - - - - ALIGNOF_POINTER p f 0 -1 0 0 _null_ _null_ _null_ ));

src/include/commands/event_trigger.h

@@ -0,0 +1,28 @@
+/*-------------------------------------------------------------------------
+ *
+ * event_trigger.h
+ *	  Declarations for command trigger handling.
+ *
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/commands/event_trigger.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef EVENT_TRIGGER_H
+#define EVENT_TRIGGER_H
+
+#include "catalog/pg_event_trigger.h"
+#include "nodes/parsenodes.h"
+
+extern void CreateEventTrigger(CreateEventTrigStmt *stmt);
+extern void RemoveEventTriggerById(Oid ctrigOid);
+extern Oid	get_event_trigger_oid(const char *trigname, bool missing_ok);
+
+extern void AlterEventTrigger(AlterEventTrigStmt *stmt);
+extern void RenameEventTrigger(const char* trigname, const char *newname);
+extern void AlterEventTriggerOwner(const char *name, Oid newOwnerId);
+extern void AlterEventTriggerOwner_oid(Oid, Oid newOwnerId);
+
+#endif   /* EVENT_TRIGGER_H */

src/include/nodes/nodes.h

@@ -357,6 +357,8 @@ typedef enum NodeTag
 	T_CreateExtensionStmt,
 	T_AlterExtensionStmt,
 	T_AlterExtensionContentsStmt,
+	T_CreateEventTrigStmt,
+	T_AlterEventTrigStmt,
 
 	/*
 	 * TAGS FOR PARSE TREE NODES (parsenodes.h)

src/include/nodes/parsenodes.h

@@ -1113,6 +1113,7 @@ typedef enum ObjectType
 	OBJECT_CONVERSION,
 	OBJECT_DATABASE,
 	OBJECT_DOMAIN,
+	OBJECT_EVENT_TRIGGER,
 	OBJECT_EXTENSION,
 	OBJECT_FDW,
 	OBJECT_FOREIGN_SERVER,
@@ -1731,6 +1732,32 @@ typedef struct CreateTrigStmt
 } CreateTrigStmt;
 
 /* ----------------------
+ *		Create EVENT TRIGGER Statement
+ * ----------------------
+ */
+typedef struct CreateEventTrigStmt
+{
+	NodeTag		type;
+	char	   *trigname;		/* TRIGGER's name */
+	char	   *eventname;		/* event's identifier */
+	List	   *whenclause;		/* list of DefElems indicating filtering */
+	List	   *funcname;		/* qual. name of function to call */
+} CreateEventTrigStmt;
+
+/* ----------------------
+ *		Alter EVENT TRIGGER Statement
+ * ----------------------
+ */
+typedef struct AlterEventTrigStmt
+{
+	NodeTag		type;
+	char	   *trigname;		/* TRIGGER's name */
+	char        tgenabled;		/* trigger's firing configuration WRT
+								 * session_replication_role */
+} AlterEventTrigStmt;
+
+/* ----------------------
+ *		Create/Drop PROCEDURAL LANGUAGE Statements
  *		Create PROCEDURAL LANGUAGE Statements
  * ----------------------
  */

src/include/parser/kwlist.h

@@ -141,6 +141,7 @@ PG_KEYWORD("encrypted", ENCRYPTED, UNRESERVED_KEYWORD)
 PG_KEYWORD("end", END_P, RESERVED_KEYWORD)
 PG_KEYWORD("enum", ENUM_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("escape", ESCAPE, UNRESERVED_KEYWORD)
+PG_KEYWORD("event", EVENT, UNRESERVED_KEYWORD)
 PG_KEYWORD("except", EXCEPT, RESERVED_KEYWORD)
 PG_KEYWORD("exclude", EXCLUDE, UNRESERVED_KEYWORD)
 PG_KEYWORD("excluding", EXCLUDING, UNRESERVED_KEYWORD)

src/include/utils/acl.h

@@ -195,6 +195,7 @@ typedef enum AclObjectKind
 	ACL_KIND_TSCONFIGURATION,	/* pg_ts_config */
 	ACL_KIND_FDW,				/* pg_foreign_data_wrapper */
 	ACL_KIND_FOREIGN_SERVER,	/* pg_foreign_server */
+	ACL_KIND_EVENT_TRIGGER,		/* pg_event_trigger */
 	ACL_KIND_EXTENSION,			/* pg_extension */
 	MAX_ACL_KIND				/* MUST BE LAST */
 } AclObjectKind;
@@ -322,6 +323,7 @@ extern bool pg_ts_dict_ownercheck(Oid dict_oid, Oid roleid);
 extern bool pg_ts_config_ownercheck(Oid cfg_oid, Oid roleid);
 extern bool pg_foreign_data_wrapper_ownercheck(Oid srv_oid, Oid roleid);
 extern bool pg_foreign_server_ownercheck(Oid srv_oid, Oid roleid);
+extern bool pg_event_trigger_ownercheck(Oid et_oid, Oid roleid);
 extern bool pg_extension_ownercheck(Oid ext_oid, Oid roleid);
 extern bool has_createrole_privilege(Oid roleid);
 

src/include/utils/builtins.h

@@ -532,6 +532,8 @@ extern Datum void_recv(PG_FUNCTION_ARGS);
 extern Datum void_send(PG_FUNCTION_ARGS);
 extern Datum trigger_in(PG_FUNCTION_ARGS);
 extern Datum trigger_out(PG_FUNCTION_ARGS);
+extern Datum event_trigger_in(PG_FUNCTION_ARGS);
+extern Datum event_trigger_out(PG_FUNCTION_ARGS);
 extern Datum language_handler_in(PG_FUNCTION_ARGS);
 extern Datum language_handler_out(PG_FUNCTION_ARGS);
 extern Datum fdw_handler_in(PG_FUNCTION_ARGS);

src/include/utils/syscache.h

@@ -54,6 +54,8 @@ enum SysCacheIdentifier
 	DEFACLROLENSPOBJ,
 	ENUMOID,
 	ENUMTYPOIDNAME,
+	EVENTTRIGGERNAME,
+	EVENTTRIGGEROID,
 	FOREIGNDATAWRAPPERNAME,
 	FOREIGNDATAWRAPPEROID,
 	FOREIGNSERVERNAME,