And a few minutes later the archiver-process with the same process-id has written a file from ..8.. line:
postgres 11502 0.0 0.0 161096724 3112 ? Ss Jan29 0:12 postgres: autovacuum launcher process postgres 11503 0.0 0.0 20136 884 ? Ss Jan29 0:10 postgres: archiver process last was 000000010000008E00000058 postgres 11504 0.0 0.0 20816 1412 ? Ss Jan29 0:54 postgres: stats collector process Am i missing something ? Thanks, Neil 2013/1/31 Neil Worden <nworden1...@gmail.com> > > Btw, ps shows: > > postgres@darkblue:/data/pgdata/pg_xlog$ ps aux | grep post > postgres 11496 0.1 0.9 161018232 3696076 ? S Jan29 2:49 > postmaster -i -D /data/pgdata > postgres 11499 0.0 1.6 161097088 6450616 ? Ss Jan29 1:39 postgres: > checkpointer process > postgres 11500 0.0 0.3 161095036 1414612 ? Ss Jan29 0:12 postgres: > writer process > postgres 11501 0.0 0.0 161095036 17328 ? Ss Jan29 0:05 postgres: > wal writer process > postgres 11502 0.0 0.0 161096724 3112 ? Ss Jan29 0:11 postgres: > autovacuum launcher process > postgres 11503 0.0 0.0 20136 884 ? Ss Jan29 0:10 postgres: > archiver process last was 000000010000006E00000034 > postgres 11504 0.0 0.0 20816 1412 ? Ss Jan29 0:53 postgres: > stats collector process > postgres 11507 0.0 0.0 161096264 2652 ? Ss Jan29 1:08 postgres: > wal sender process postgres 192.168.30.65(45640) streaming 8E/5544E650 > postgres 11864 0.0 0.0 161096136 2656 ? Ss Jan29 0:51 postgres: > wal sender process postgres 192.168.10.95(37378) streaming 8E/5544E650 > ... > > The archiver process says "last was 000000010000006E00000034" and when i > look into my wal-archive-directory i see: > > -rw------- 1 postgres postgres 16777216 Jan 31 10:24 > 000000010000006E00000033 > -rw------- 1 postgres postgres 16777216 Jan 31 10:24 > 000000010000006E00000034 > -rw------- 1 postgres postgres 16777216 Jan 29 16:03 > 000000010000008C0000008E > -rw------- 1 postgres postgres 16777216 Jan 29 16:32 > 000000010000008C0000008F > > The 6E..34 file was just written by the archiver process. But further down > at the same time this file was written: > > ... > -rw------- 1 postgres postgres 16777216 Jan 31 10:24 > 000000010000008E00000054 > > which seems to match the position of the streaming wal-senders . > > Any ideas ? > > Thanks, Neil. > > > > > > 2013/1/31 Neil Worden <nworden1...@gmail.com> > >> >>> If your command does overwrite, then the server currently emitting the >> >>> 8D files will become unrecoverable once those files start getting >> >>> overwritten. If it refuses to overwrite, but returns a zero status, >> >>> then the server currently emitting 6D would become unrecoverable once >> >>> it reaches 8D and its "archived" files are not actually being archived >> >>> but are getting deleted from the local pg_xlog anyway. >> >> >> >> >> >> Would it not be easier to archive the different servers to different >> >> directories and eliminate the possibility of name collision between >> servers? >> >> >Easier? I would say that that is the only sane way of doing it. I >> >was pointing out the consequences of messing it up. A proper >> >archive_command will save you from some self-inflicted disasters, but >> >that does not mean I'm recommending that you should invite those >> >disasters on yourself. >> >> >If the original author is in a production environment, he desperately >> >needs to figure out what is going on, especially so if archive_command >> >is not tested and verified to obey its contract. >> >> >Cheers, >> >> >Jeff >> >> Thanks for your answers. >> >> Yes, we are in a production environment and there are definitely no two >> masters writing to the wal-archive directory, at least none that i am aware >> of. And i can assure you that we are not intentionally working on inviting >> disasters either :-). >> >> Point is, the ..6D.. line started showing up exactly after i set up the >> archive-command (which is btw: archive_command = 'test ! -f >> /data/backup/walbackup/%f && cp %p /data/backup/walbackup/%f', running on >> Ubuntu Linux Server) >> >> The situation is as follows: >> >> All concerned machines are running 9.2.2 64-bit on Ubuntu Linux Server >> 12.10, installed from source, all following exactly the same procedure. We >> have a hot-standby running to a different location over a rather thin line >> running since version 9.1 came out. That worked >> flawlessly, we only were bitten by autovacuums to prevent XID wraparounds >> that generated relatively high wal-volume and we >> were not sure whether the network connection could keep up with it before >> deleting wal-files. Since we had to physically transfer a backup once for >> other reasons, we set wal_keep_segments to 8192 to have enough >> fallback-time. >> >> The total size of the database is currently at 313 GB and we are in the >> process of rethinking our backup/emergency-strategy (currently daily full >> dumps + hot-standby for read-only queries in the other location + one >> hot-standby in the same office). >> >> So we set up another machine, intended to become a another hot_standby >> later, but for now just use it to experiment with pg_receivexlog. Since our >> current backup-strategy does not allow for PIT-recovery and we have been >> thinking about wal-archiving all the time, we decided to implement it and >> thats what we did. Now we have the two "lines" in the archive-directory. >> >> Could the the high number of wal_keep_segments have an impact ? >> Does the fact that there already were a lot of existing wal-files when i >> set up archiving and the archive-command have an impact ? >> >> Jeff, you wrote: >> >> >> And how would i restore the needed file names for recovery >> >> if i decide to keep one base-backup und then a very long chain of >> wal-files >> >> ? >> >> >There should be no need for that. >> >> When you said there would be no need for that, did you mean restoring the >> files for recovery or keeping a base-backup and the chain of wal-files ? >> >> I understand that the archive-command is responsible for not overwriting >> wal-files. But if that situation occurs, and if i understand you correctly >> it will, what do i do ? >> If the wal-archive files will be overwritten at some point in time, how >> is it possible to only have one single base-backup at time-point t and from >> then on only store the following wal-files ( however inconvenient that may >> be ) to be able to restore to any point in time after time t ? >> >> Thanks, >> >> Neil >> >> >> >> >
