Make local copy of client hostnames in backend status array.

The other strings, application_name and query string, were snapshotted to
local memory in pgstat_read_current_status(), but we forgot to do that for
client hostnames. As a result, the client hostname would appear to change in
the local copy, if the client disconnected.

Backpatch to all supported versions.

Author: Edmund Horner
Reviewed-by: Michael Paquier
Discussion: https://www.postgresql.org/message-id/CAMyN-kA7aOJzBmrYFdXcc7Z0NmW%2B5jBaf_m%3D_-77uRNyKC9r%3DA%40mail.gmail.com

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 64616a24139fc5828756634c85609924dfb03e3f..3ec23d76ddc613d0817755bc3b6ffc64e2278fa2 100644 (file)
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -2985,6 +2985,7 @@ pgstat_read_current_status(void)
    LocalPgBackendStatus *localtable;
    LocalPgBackendStatus *localentry;
    char       *localappname,
+              *localclienthostname,
               *localactivity;
 #ifdef USE_SSL
    PgBackendSSLStatus *localsslstatus;
@@ -3003,6 +3004,9 @@ pgstat_read_current_status(void)
    localappname = (char *)
        MemoryContextAlloc(pgStatLocalContext,
                           NAMEDATALEN * MaxBackends);
+   localclienthostname = (char *)
+       MemoryContextAlloc(pgStatLocalContext,
+                          NAMEDATALEN * MaxBackends);
    localactivity = (char *)
        MemoryContextAlloc(pgStatLocalContext,
                           pgstat_track_activity_query_size * MaxBackends);
@@ -3043,6 +3047,8 @@ pgstat_read_current_status(void)
                 */
                strcpy(localappname, (char *) beentry->st_appname);
                localentry->backendStatus.st_appname = localappname;
+               strcpy(localclienthostname, (char *) beentry->st_clienthostname);
+               localentry->backendStatus.st_clienthostname = localclienthostname;
                strcpy(localactivity, (char *) beentry->st_activity);
                localentry->backendStatus.st_activity = localactivity;
                localentry->backendStatus.st_ssl = beentry->st_ssl;
@@ -3074,6 +3080,7 @@ pgstat_read_current_status(void)
 
            localentry++;
            localappname += NAMEDATALEN;
+           localclienthostname += NAMEDATALEN;
            localactivity += pgstat_track_activity_query_size;
 #ifdef USE_SSL
            localsslstatus++;