1 files changed, 76 insertions, 7 deletions

diff --git a/contrib/miscutil/misc_utils.c b/contrib/miscutil/misc_utils.c
index 24d069f71c2..75184439717 100644
--- a/contrib/miscutil/misc_utils.c
+++ b/contrib/miscutil/misc_utils.c
@@ -10,12 +10,27 @@
  */
 
 #include <unistd.h>
+#include <signal.h>
+#include <string.h>
+#include <errno.h>
 
 #include "postgres.h"
+#include "access/heapam.h"
+#include "access/htup.h"
+#include "access/relscan.h"
+#include "access/skey.h"
+#include "access/tupdesc.h"
+#include "catalog/catname.h"
+#include "catalog/pg_listener.h"
+#include "storage/lmgr.h"
+#include "utils/fmgr.h"
 #include "utils/palloc.h"
+#include "utils/rel.h"
+#include "utils/tqual.h"
 
 #include "misc_utils.h"
-#include "assert_test.h"
+
+#define MIN(x,y)	((x)<=(y) ? (x) : (y))
 
 extern int	ExecutorLimit(int limit);
 extern void Async_Unlisten(char *relname, int pid);
@@ -23,7 +38,6 @@ extern int	assertTest(int val);
 
 #ifdef ASSERT_CHECKING_TEST
 extern int	assertEnable(int val);
-
 #endif
 
 int
@@ -57,6 +71,62 @@ min(int x, int y)
 	return ((x < y) ? x : y);
 }
 
+/*
+ * Return the number of active listeners on a relation name.
+ */
+int
+active_listeners(text *relname)
+{
+	HeapTuple	lTuple;
+	Relation	lRel;
+	HeapScanDesc sRel;
+	TupleDesc	tdesc;
+	ScanKeyData key;
+	Datum		d;
+	bool		isnull;
+	int			len, pid;
+	int			count = 0;
+	int			ourpid = getpid();
+	char		listen_name[NAMEDATALEN];
+
+	lRel = heap_openr(ListenerRelationName);
+	tdesc = RelationGetDescr(lRel);
+	LockRelation(lRel, AccessShareLock);
+
+	if (relname && (VARSIZE(relname) > VARHDRSZ)) {
+		len = MIN(VARSIZE(relname)-VARHDRSZ, NAMEDATALEN-1);
+		strncpy(listen_name, VARDATA(relname), len);
+		listen_name[len] = '\0';
+		ScanKeyEntryInitialize(&key, 0,
+							   Anum_pg_listener_relname,
+							   F_NAMEEQ,
+							   PointerGetDatum(listen_name));
+		sRel = heap_beginscan(lRel, 0, SnapshotNow, 1, &key);
+	} else {
+		sRel = heap_beginscan(lRel, 0, SnapshotNow, 0, (ScanKey)NULL);
+	}
+
+	while (HeapTupleIsValid(lTuple = heap_getnext(sRel, 0)))
+	{
+		d = heap_getattr(lTuple, Anum_pg_listener_pid, tdesc, &isnull);
+		pid = DatumGetInt32(d);
+#ifdef HAVE_KILL
+		if ((pid == ourpid) || (kill(pid, SIGTSTP) == 0)) {
+			/* elog(NOTICE, "%d ok", pid); */
+			count++;
+		}
+#else
+		count++;
+#endif
+	}
+	heap_endscan(sRel);
+
+	UnlockRelation(lRel, AccessShareLock);
+	heap_close(lRel);
+
+	return count;
+}
+
 int
 assert_enable(int val)
 {
@@ -69,15 +139,14 @@ assert_test(int val)
 {
 	return assertTest(val);
 }
-
 #endif
 
 /* end of file */
 
 /*
- * Local variables:
- *	tab-width: 4
- *	c-indent-level: 4
- *	c-basic-offset: 4
+ * Local Variables:
+ *  tab-width: 4
+ *  c-indent-level: 4
+ *  c-basic-offset: 4
  * End:
  */