wait_event_wal_fsync.patch

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index c2adb22..ef0addd 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -1682,6 +1682,10 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>WALWrite</literal></entry>
          <entry>Waiting for a write to a WAL file.</entry>
         </row>
+        <row>
+         <entry><literal>WALFsync</literal></entry>
+         <entry>Waiting for a fsync for WAL segment.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 1a419aa..0956655 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -10156,6 +10156,7 @@ assign_xlog_sync_method(int new_sync_method, void *extra)
 void
 issue_xlog_fsync(int fd, XLogSegNo segno)
 {
+	pgstat_report_wait_start(WAIT_EVENT_WAL_FSYNC);
 	switch (sync_method)
 	{
 		case SYNC_METHOD_FSYNC:
@@ -10191,6 +10192,7 @@ issue_xlog_fsync(int fd, XLogSegNo segno)
 			elog(PANIC, "unrecognized wal_sync_method: %d", sync_method);
 			break;
 	}
+	pgstat_report_wait_end();
 }
 
 /*
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 084573e..adbf6af 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3931,6 +3931,9 @@ pgstat_get_wait_io(WaitEventIO w)
 		case WAIT_EVENT_WAL_WRITE:
 			event_name = "WALWrite";
 			break;
+		case WAIT_EVENT_WAL_FSYNC:
+			event_name = "WALFsync";
+			break;
 
 			/* no default case, so that compiler will warn */
 	}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index be2f592..b76074b 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -922,7 +922,8 @@ typedef enum
 	WAIT_EVENT_WAL_INIT_WRITE,
 	WAIT_EVENT_WAL_READ,
 	WAIT_EVENT_WAL_SYNC_METHOD_ASSIGN,
-	WAIT_EVENT_WAL_WRITE
+	WAIT_EVENT_WAL_WRITE,
+	WAIT_EVENT_WAL_FSYNC
 } WaitEventIO;
 
 /* ----------