proclist.diff

diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index bfa8499..fc9221b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -287,6 +287,14 @@ void
 InitProcess(void)
 {
 	PGPROC	   *volatile *procgloballist;
+#define LIST_TYPE_ENTRY(e) [(e)] = (#e)
+	enum listType { autovac, bgworker, backend } which;
+	char const * const listTypeNames[] = {
+		LIST_TYPE_ENTRY(autovac),
+		LIST_TYPE_ENTRY(bgworker),
+		LIST_TYPE_ENTRY(backend)
+	};
+#undef LIST_TYPE_ENTRY
 
 	/*
 	 * ProcGlobal should be set up already (if we are a backend, we inherit
@@ -300,11 +308,11 @@ InitProcess(void)
 
 	/* Decide which list should supply our PGPROC. */
 	if (IsAnyAutoVacuumProcess())
-		procgloballist = &ProcGlobal->autovacFreeProcs;
+		which = autovac, procgloballist = &ProcGlobal->autovacFreeProcs;
 	else if (IsBackgroundWorker)
-		procgloballist = &ProcGlobal->bgworkerFreeProcs;
+		which = bgworker, procgloballist = &ProcGlobal->bgworkerFreeProcs;
 	else
-		procgloballist = &ProcGlobal->freeProcs;
+		which = backend, procgloballist = &ProcGlobal->freeProcs;
 
 	/*
 	 * Try to get a proc struct from the appropriate free list.  If this
@@ -329,13 +337,12 @@ InitProcess(void)
 		/*
 		 * If we reach here, all the PGPROCs are in use.  This is one of the
 		 * possible places to detect "too many backends", so give the standard
-		 * error message.  XXX do we need to give a different failure message
-		 * in the autovacuum case?
+		 * error message.
 		 */
 		SpinLockRelease(ProcStructLock);
 		ereport(FATAL,
 				(errcode(ERRCODE_TOO_MANY_CONNECTIONS),
-				 errmsg("sorry, too many clients already")));
+				 errmsg("%s proc list saturated", listTypeNames[which])));
 	}
 	MyPgXact = &ProcGlobal->allPgXact[MyProc->pgprocno];