From 3d39244e6e7374febff59eba338f7a82f696a618 Mon Sep 17 00:00:00 2001
From: Magnus Hagander <magnus@hagander.net>
Date: Fri, 30 Sep 2016 11:19:30 +0200
Subject: [PATCH] Retry opening new segments in pg_xlogdump --folllow
There is a small window between when the server closes out the existing
segment and the new one is created. Put a loop around the open call in
this case to make sure we wait for the new file to actually appear.
---
src/bin/pg_xlogdump/pg_xlogdump.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/src/bin/pg_xlogdump/pg_xlogdump.c b/src/bin/pg_xlogdump/pg_xlogdump.c
index 02575eb1c57..9ad9321e1f9 100644
--- a/src/bin/pg_xlogdump/pg_xlogdump.c
+++ b/src/bin/pg_xlogdump/pg_xlogdump.c
@@ -249,6 +249,7 @@ XLogDumpXLogRead(const char *directory, TimeLineID timeline_id,
if (sendFile < 0 || !XLByteInSeg(recptr, sendSegNo))
{
char fname[MAXFNAMELEN];
+ int tries;
/* Switch to another logfile segment */
if (sendFile >= 0)
@@ -258,7 +259,30 @@ XLogDumpXLogRead(const char *directory, TimeLineID timeline_id,
XLogFileName(fname, timeline_id, sendSegNo);
- sendFile = fuzzy_open_file(directory, fname);
+ /*
+ * In follow mode there is a short period of time after the
+ * server has written the end of the previous file before the
+ * new file is available. So we loop for 5 seconds looking
+ * for the file to appear before giving up.
+ */
+ for (tries = 0; tries < 10; tries++)
+ {
+ sendFile = fuzzy_open_file(directory, fname);
+ if (sendFile >= 0)
+ break;
+ if (errno == ENOENT)
+ {
+ int save_errno = errno;
+
+ /* File not there yet, try again */
+ pg_usleep(500 * 1000);
+
+ errno = save_errno;
+ continue;
+ }
+ /* Any other error, fall through and fail */
+ break;
+ }
if (sendFile < 0)
fatal_error("could not find file \"%s\": %s",
--
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