Minor API cleanup for async notifications: we can only register the

Neil Conway · Neil Conway · commit f59175d72ff9 · 2005-10-06T21:30:39.000Z
current backend in pg_listener, so there is little point in making
the PID to register part of async.c's public API. Other minor tweaks.
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.124 2005/08/20 00:39:53 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.125 2005/10/06 21:30:32 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -146,13 +146,10 @@ static void ClearPendingNotifies(void);
  *		Actual notification happens during transaction commit.
  *		^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  *
- * Results:
- *		XXX
- *
  *--------------------------------------------------------------
  */
 void
-Async_Notify(char *relname)
+Async_Notify(const char *relname)
 {
 	if (Trace_notify)
 		elog(DEBUG1, "Async_Notify(%s)", relname);
@@ -180,19 +177,16 @@ Async_Notify(char *relname)
  *
  *		This is executed by the SQL listen command.
  *
- *		Register a backend (identified by its Unix PID) as listening
- *		on the specified relation.
- *
- * Results:
- *		XXX
+ *		Register the current backend as listening on the specified
+ *		relation.
  *
  * Side effects:
  *		pg_listener is updated.
  *
  *--------------------------------------------------------------
  */
 void
-Async_Listen(char *relname, int pid)
+Async_Listen(const char *relname)
 {
 	Relation	lRel;
 	HeapScanDesc scan;
@@ -203,7 +197,7 @@ Async_Listen(char *relname, int pid)
 	bool		alreadyListener = false;
 
 	if (Trace_notify)
-		elog(DEBUG1, "Async_Listen(%s,%d)", relname, pid);
+		elog(DEBUG1, "Async_Listen(%s,%d)", relname, MyProcPid);
 
 	lRel = heap_open(ListenerRelationId, ExclusiveLock);
 
@@ -213,7 +207,7 @@ Async_Listen(char *relname, int pid)
 	{
 		Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(tuple);
 
-		if (listener->listenerpid == pid &&
+		if (listener->listenerpid == MyProcPid &&
 		  strncmp(NameStr(listener->relname), relname, NAMEDATALEN) == 0)
 		{
 			alreadyListener = true;
@@ -241,7 +235,7 @@ Async_Listen(char *relname, int pid)
 
 	i = 0;
 	values[i++] = (Datum) relname;
-	values[i++] = (Datum) pid;
+	values[i++] = (Datum) MyProcPid;
 	values[i++] = (Datum) 0;	/* no notifies pending */
 
 	tuple = heap_formtuple(RelationGetDescr(lRel), values, nulls);
@@ -271,19 +265,16 @@ Async_Listen(char *relname, int pid)
  *
  *		This is executed by the SQL unlisten command.
  *
- *		Remove the backend from the list of listening backends
+ *		Remove the current backend from the list of listening backends
  *		for the specified relation.
  *
- * Results:
- *		XXX
- *
  * Side effects:
  *		pg_listener is updated.
  *
  *--------------------------------------------------------------
  */
 void
-Async_Unlisten(char *relname, int pid)
+Async_Unlisten(const char *relname)
 {
 	Relation	lRel;
 	HeapScanDesc scan;
@@ -297,7 +288,7 @@ Async_Unlisten(char *relname, int pid)
 	}
 
 	if (Trace_notify)
-		elog(DEBUG1, "Async_Unlisten(%s,%d)", relname, pid);
+		elog(DEBUG1, "Async_Unlisten(%s,%d)", relname, MyProcPid);
 
 	lRel = heap_open(ListenerRelationId, ExclusiveLock);
 
@@ -306,7 +297,7 @@ Async_Unlisten(char *relname, int pid)
 	{
 		Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(tuple);
 
-		if (listener->listenerpid == pid &&
+		if (listener->listenerpid == MyProcPid &&
 		  strncmp(NameStr(listener->relname), relname, NAMEDATALEN) == 0)
 		{
 			/* Found the matching tuple, delete it */
diff --git 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 1.243 2005/08/01 04:03:57 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.244 2005/10/06 21:30:36 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -823,15 +823,15 @@ ProcessUtility(Node *parsetree,
 			{
 				ListenStmt *stmt = (ListenStmt *) parsetree;
 
-				Async_Listen(stmt->relation->relname, MyProcPid);
+				Async_Listen(stmt->relation->relname);
 			}
 			break;
 
 		case T_UnlistenStmt:
 			{
 				UnlistenStmt *stmt = (UnlistenStmt *) parsetree;
 
-				Async_Unlisten(stmt->relation->relname, MyProcPid);
+				Async_Unlisten(stmt->relation->relname);
 			}
 			break;
 
diff --git a/src/include/commands/async.h b/src/include/commands/async.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/commands/async.h,v 1.28 2005/06/17 22:32:49 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/commands/async.h,v 1.29 2005/10/06 21:30:39 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,9 +16,9 @@
 extern bool Trace_notify;
 
 /* notify-related SQL statements */
-extern void Async_Notify(char *relname);
-extern void Async_Listen(char *relname, int pid);
-extern void Async_Unlisten(char *relname, int pid);
+extern void Async_Notify(const char *relname);
+extern void Async_Listen(const char *relname);
+extern void Async_Unlisten(const char *relname);
 
 /* perform (or cancel) outbound notify processing at transaction commit */
 extern void AtCommit_Notify(void);

Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@`
`7`	`7`	`* Portions Copyright (c) 1994, Regents of the University of California`
`8`	`8`	`*`
`9`	`9`	`* IDENTIFICATION`
`10`		`- * $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.124 2005/08/20 00:39:53 tgl Exp $`
	`10`	`+ * $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.125 2005/10/06 21:30:32 neilc Exp $`
`11`	`11`	`*`
`12`	`12`	`*-------------------------------------------------------------------------`
`13`	`13`	`*/`
`@@ -146,13 +146,10 @@ static void ClearPendingNotifies(void);`
`146`	`146`	`* Actual notification happens during transaction commit.`
`147`	`147`	`* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^`
`148`	`148`	`*`
`149`		`- * Results:`
`150`		`- * XXX`
`151`		`- *`
`152`	`149`	`*--------------------------------------------------------------`
`153`	`150`	`*/`
`154`	`151`	`void`
`155`		`-Async_Notify(char *relname)`
	`152`	`+Async_Notify(const char *relname)`
`156`	`153`	`{`
`157`	`154`	`if (Trace_notify)`
`158`	`155`	`elog(DEBUG1, "Async_Notify(%s)", relname);`
`@@ -180,19 +177,16 @@ Async_Notify(char *relname)`
`180`	`177`	`*`
`181`	`178`	`* This is executed by the SQL listen command.`
`182`	`179`	`*`
`183`		`- * Register a backend (identified by its Unix PID) as listening`
`184`		`- * on the specified relation.`
`185`		`- *`
`186`		`- * Results:`
`187`		`- * XXX`
	`180`	`+ * Register the current backend as listening on the specified`
	`181`	`+ * relation.`
`188`	`182`	`*`
`189`	`183`	`* Side effects:`
`190`	`184`	`* pg_listener is updated.`
`191`	`185`	`*`
`192`	`186`	`*--------------------------------------------------------------`
`193`	`187`	`*/`
`194`	`188`	`void`
`195`		`-Async_Listen(char *relname, int pid)`
	`189`	`+Async_Listen(const char *relname)`
`196`	`190`	`{`
`197`	`191`	`Relation lRel;`
`198`	`192`	`HeapScanDesc scan;`
`@@ -203,7 +197,7 @@ Async_Listen(char *relname, int pid)`
`203`	`197`	`bool alreadyListener = false;`
`204`	`198`
`205`	`199`	`if (Trace_notify)`
`206`		`- elog(DEBUG1, "Async_Listen(%s,%d)", relname, pid);`
	`200`	`+ elog(DEBUG1, "Async_Listen(%s,%d)", relname, MyProcPid);`
`207`	`201`
`208`	`202`	`lRel = heap_open(ListenerRelationId, ExclusiveLock);`
`209`	`203`
`@@ -213,7 +207,7 @@ Async_Listen(char *relname, int pid)`
`213`	`207`	`{`
`214`	`208`	`Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(tuple);`
`215`	`209`
`216`		`- if (listener->listenerpid == pid &&`
	`210`	`+ if (listener->listenerpid == MyProcPid &&`
`217`	`211`	`strncmp(NameStr(listener->relname), relname, NAMEDATALEN) == 0)`
`218`	`212`	`{`
`219`	`213`	`alreadyListener = true;`
`@@ -241,7 +235,7 @@ Async_Listen(char *relname, int pid)`
`241`	`235`
`242`	`236`	`i = 0;`
`243`	`237`	`values[i++] = (Datum) relname;`
`244`		`- values[i++] = (Datum) pid;`
	`238`	`+ values[i++] = (Datum) MyProcPid;`
`245`	`239`	`values[i++] = (Datum) 0; /* no notifies pending */`
`246`	`240`
`247`	`241`	`tuple = heap_formtuple(RelationGetDescr(lRel), values, nulls);`
`@@ -271,19 +265,16 @@ Async_Listen(char *relname, int pid)`
`271`	`265`	`*`
`272`	`266`	`* This is executed by the SQL unlisten command.`
`273`	`267`	`*`
`274`		`- * Remove the backend from the list of listening backends`
	`268`	`+ * Remove the current backend from the list of listening backends`
`275`	`269`	`* for the specified relation.`
`276`	`270`	`*`
`277`		`- * Results:`
`278`		`- * XXX`
`279`		`- *`
`280`	`271`	`* Side effects:`
`281`	`272`	`* pg_listener is updated.`
`282`	`273`	`*`
`283`	`274`	`*--------------------------------------------------------------`
`284`	`275`	`*/`
`285`	`276`	`void`
`286`		`-Async_Unlisten(char *relname, int pid)`
	`277`	`+Async_Unlisten(const char *relname)`
`287`	`278`	`{`
`288`	`279`	`Relation lRel;`
`289`	`280`	`HeapScanDesc scan;`
`@@ -297,7 +288,7 @@ Async_Unlisten(char *relname, int pid)`
`297`	`288`	`}`
`298`	`289`
`299`	`290`	`if (Trace_notify)`
`300`		`- elog(DEBUG1, "Async_Unlisten(%s,%d)", relname, pid);`
	`291`	`+ elog(DEBUG1, "Async_Unlisten(%s,%d)", relname, MyProcPid);`
`301`	`292`
`302`	`293`	`lRel = heap_open(ListenerRelationId, ExclusiveLock);`
`303`	`294`
`@@ -306,7 +297,7 @@ Async_Unlisten(char *relname, int pid)`
`306`	`297`	`{`
`307`	`298`	`Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(tuple);`
`308`	`299`
`309`		`- if (listener->listenerpid == pid &&`
	`300`	`+ if (listener->listenerpid == MyProcPid &&`
`310`	`301`	`strncmp(NameStr(listener->relname), relname, NAMEDATALEN) == 0)`
`311`	`302`	`{`
`312`	`303`	`/* Found the matching tuple, delete it */`
Original file line number	Diff line number	Diff line change
`@@ -10,7 +10,7 @@`
`10`	`10`	`*`
`11`	`11`	`*`
`12`	`12`	`* IDENTIFICATION`
`13`		`- * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.243 2005/08/01 04:03:57 tgl Exp $`
	`13`	`+ * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.244 2005/10/06 21:30:36 neilc Exp $`
`14`	`14`	`*`
`15`	`15`	`*-------------------------------------------------------------------------`
`16`	`16`	`*/`
`@@ -823,15 +823,15 @@ ProcessUtility(Node *parsetree,`
`823`	`823`	`{`
`824`	`824`	`ListenStmt stmt = (ListenStmt ) parsetree;`
`825`	`825`
`826`		`- Async_Listen(stmt->relation->relname, MyProcPid);`
	`826`	`+ Async_Listen(stmt->relation->relname);`
`827`	`827`	`}`
`828`	`828`	`break;`
`829`	`829`
`830`	`830`	`case T_UnlistenStmt:`
`831`	`831`	`{`
`832`	`832`	`UnlistenStmt stmt = (UnlistenStmt ) parsetree;`
`833`	`833`
`834`		`- Async_Unlisten(stmt->relation->relname, MyProcPid);`
	`834`	`+ Async_Unlisten(stmt->relation->relname);`
`835`	`835`	`}`
`836`	`836`	`break;`
`837`	`837`