From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 2 Apr 2014 01:30:11 +0000 (-0400)
Subject: Fix bugs in manipulation of PgBackendStatus.st_clienthostname.
X-Git-Tag: REL9_3_5~127
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6cb229d5ad77112156946c42cc91b8cba204072e;p=postgresql

Fix bugs in manipulation of PgBackendStatus.st_clienthostname.

Initialization of this field was not being done according to the
st_changecount protocol (it has to be done within the changecount increment
range, not outside).  And the test to see if the value should be reported
as null was wrong.  Noted while perusing uses of Port.remote_hostname.

This was wrong from the introduction of this code (commit 4a25bc145),
so back-patch to 9.1.
---

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 0fd44957d9..1b8b6c7357 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -2518,7 +2518,11 @@ pgstat_bestart(void)
 	beentry->st_databaseid = MyDatabaseId;
 	beentry->st_userid = userid;
 	beentry->st_clientaddr = clientaddr;
-	beentry->st_clienthostname[0] = '\0';
+	if (MyProcPort && MyProcPort->remote_hostname)
+		strlcpy(beentry->st_clienthostname, MyProcPort->remote_hostname,
+				NAMEDATALEN);
+	else
+		beentry->st_clienthostname[0] = '\0';
 	beentry->st_waiting = false;
 	beentry->st_state = STATE_UNDEFINED;
 	beentry->st_appname[0] = '\0';
@@ -2531,9 +2535,6 @@ pgstat_bestart(void)
 	beentry->st_changecount++;
 	Assert((beentry->st_changecount & 1) == 0);
 
-	if (MyProcPort && MyProcPort->remote_hostname)
-		strlcpy(beentry->st_clienthostname, MyProcPort->remote_hostname, NAMEDATALEN);
-
 	/* Update app name to current GUC setting */
 	if (application_name)
 		pgstat_report_appname(application_name);
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 5a03b15c46..66e896dc34 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -724,7 +724,8 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 						clean_ipv6_addr(beentry->st_clientaddr.addr.ss_family, remote_host);
 						values[11] = DirectFunctionCall1(inet_in,
 											   CStringGetDatum(remote_host));
-						if (beentry->st_clienthostname)
+						if (beentry->st_clienthostname &&
+							beentry->st_clienthostname[0])
 							values[12] = CStringGetTextDatum(beentry->st_clienthostname);
 						else
 							nulls[12] = true;