The standby log:
-> 2010-11-14 17:40:16 MST - 887 -LOG: database system was shut down in
recovery at 2010-11-14 17:40:10 MST
-> 2010-11-14 17:40:16 MST - 887 -LOG: entering standby mode
-> 2010-11-14 17:40:16 MST - 887 -LOG: consistent recovery state reached at
3/3988FF8
-> 2010-11-14 17:40:16 MST - 887 -LOG: redo starts at 3/3988F68
-> 2010-11-14 17:40:16 MST - 887 -LOG: invalid record length at 3/3988FF8
-> 2010-11-14 17:40:16 MST - 885 -LOG: database system is ready to accept
read only connections
-> 2010-11-14 17:40:16 MST - 890 -LOG: streaming replication successfully
connected to primary
-> 2010-11-15 02:24:26 MST - 890 -FATAL: could not receive data from WAL
stream: FATAL: requested WAL segment 000000010000000300000004 has already been
removed
-> 2010-11-15 02:24:26 MST - 887 -LOG: unexpected pageaddr 2/B9BF2000 in log
file 3, segment 4, offset 12525568
-> 2010-11-15 02:24:27 MST - 2790 -LOG: streaming replication successfully
connected to primary
-> 2010-11-15 02:24:27 MST - 2790 -FATAL: could not receive data from WAL
stream: FATAL: requested WAL segment 000000010000000300000004 has already been
removed
-> 2010-11-15 02:24:32 MST - 2791 -LOG: streaming replication successfully
connected to primary
-> 2010-11-15 02:24:32 MST - 2791 -FATAL: could not receive data from WAL
stream: FATAL: requested WAL segment 000000010000000300000004 has already been
removed
...
Now, the standby is geographically isolated from the master, so it's over an
internet connection, so it's not a shock that with a large enough update and
wal_keep_segments not large enough, speed of disk would outrun speed of network
sufficiently for this to happen.
But as far as I know there was almost no write activity at 2am, no active users
at all, no batch processing. There is a pg_dumpall that kicks off at 2am and
these errors start about the same time that it finished. I also did the
original synch and standby launch immediately after a mass update before
autovacuum had a chance to run, so at some point there would be a lot of tuples
marked dead.
wal_keep_segments was at 64, the first segment still around was
000000010000000300000010, checkpoint_segments was 16. In the midst of the
pg_dumpall the master logs do show messages about checkpoint flushing too
often. The 70ish log segments still around show mod times right around 2:23,
progressing a second or so each, whereas they were created over a much longer
period going back to the day before.
1 question: what happened here? Why were log files created the day before
updated?
1 suggestion: would it be possible to not delete wal segments that are needed
by a currently attached standby?
--
Scott Ribe
scott_r...@elevated-dev.com
http://www.elevated-dev.com/
(303) 722-0567 voice
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