Fix archiver for issue #358

check_pgactivity

@@ -2034,13 +2034,13 @@ sub check_archiver {
                 ELSE 0
                 END, last_archived_wal, last_failed_wal,
                 /* mod time of the next wal to archive
-                * executed only if superuser */
+                * executed only if superuser and archiving is on */
                 (SELECT extract('epoch' from (current_timestamp -
                         (pg_stat_file('pg_wal/'||pg_walfile_name(
                            (to_hex((last_archived_off+1)/4294967296)
                            ||'/'||to_hex((last_archived_off+1)%4294967296))::pg_lsn
                       ), true)).modification ))
-                 WHERE current_setting('is_superuser')::bool
+                 WHERE (current_setting('is_superuser')::bool AND current_setting('archive_mode') <> 'off')
                 ) AS oldest
         FROM (
             SELECT last_archived_wal, last_archived_time, last_failed_wal,
@@ -2102,12 +2102,15 @@ sub check_archiver {
                 ELSE 0
                 END, last_archived_wal, last_failed_wal,
                 /* mod time of the next wal to archive */
-                extract('epoch' from (current_timestamp -
+		CASE WHEN current_setting('archive_mode')::bool IS TRUE
+                THEN extract('epoch' from (current_timestamp -
                     (pg_stat_file('pg_wal/'||pg_walfile_name(
                         (to_hex((last_archived_off+1)/4294967296)
                         ||'/'||to_hex((last_archived_off+1)%4294967296))::pg_lsn
                     ), true)).modification )
-                ) AS oldest
+		)
+               ELSE NULL
+               END AS oldest
         FROM (
             SELECT last_archived_wal, last_archived_time, last_failed_wal,
                 walsegsize,

t/01-archiver.t

@@ -16,7 +16,7 @@ my $node      = pgNode->get_new_node('prod');
 my $pga_data = "$TestLib::tmp_check/pga.data";
 my $wal;
 my @stdout;
-my $num_tests = 25;
+my $num_tests = 29;
 
 $node->init(has_archiving => 1);
 
@@ -157,6 +157,44 @@ SKIP: {
     );
 }
 
+# Specific tests for PG9.4+, edge cases with pg_stat_archiver
+# Covers issue #358 and #384
+SKIP: {
+    skip "checking with non superuser role is not supported before v10", 4
+        if $node->version < '10';
+
+    # repair archiving
+    $node->append_conf('postgresql.conf', "archive_command = 'true'");
+    $node->reload;
+    sleep(1);
+    # Turn archiving off, pg_stat_archiver remains
+    # see issue #358 and #384
+    $node->stop;
+    $node->append_conf('postgresql.conf', "archive_mode = 'off'");
+    $node->start;
+    $node->psql('template1', 'insert into t select generate_series(20001,30000) as i');
+    $wal = $node->switch_wal;
+
+    # Current behavior is to bail out an error "could not stat file"
+
+    $node->command_checks_all( [
+        './check_pgactivity', '--service'     => 'archiver',
+                              '--username'    => $ENV{'USER'} || 'postgres',
+                              '--status-file' => $pga_data,
+                              '--format'      => 'human'
+        ],
+        0,
+        [
+          # Should not return an error in this case
+          qr/^Service  *: POSTGRES_ARCHIVER$/m,
+          qr/^Returns  *: 0 \(OK\)$/m,
+        ],
+        [ qr/^$/ ],
+        'do not bail out when archiver is off'
+    );
+
+}
+
 ### End of tests ###
 
 $node->stop( 'immediate' );