We are running pg 7.1.3. x86 Redhat 6.1 with 2.4.17 and glibc 2.2.2. We have several s/w subsystems which keep some pg backends open for a VERY period of time. (Well the whole time the machine is powered up.), and others which have a short lifetime when connected to pg backends.
The total amount of data stored within the database is relatively small < 30Mb. We have seen occurences when pg runs out of disk space (currently it has approx 90Mb allocated to it) and fails. In some circumstances we have noticed that some backends still have file descriptors open to /pg_xlog/0000* files even though they have obviously been deleted some while ago when that wal file was no longer referenced. Is this expected behaviour? Or just an artifact that the backend life is prolonged in our use of pg. We have started experimenting with wal_files and checkpoint_segment settings to see how that affects both the number of wal file created and whether or not they get deleted correctly. At the time of writing, even with wal_files =1 and checkpoint_segment =1 pg appeared to have one current wal file and one which had been deleted and still referenced by a backend. (You can observer these by "ls -l /proc/*/fd/* | grep xlog" ) eg: lrwx------ 1 postgres postgres 64 Apr 22 21:20 /proc/1576/fd/36 -> /db/live/pg_xlog/0000000000000002 (deleted) lrwx------ 1 postgres postgres 64 Apr 22 21:20 /proc/1613/fd/36 -> /db/live/pg_xlog/0000000000000000 (deleted) lrwx------ 1 postgres postgres 64 Apr 22 21:20 /proc/1672/fd/36 -> /db/live/pg_xlog/0000000000000000 (deleted) lrwx------ 1 postgres postgres 64 Apr 22 21:20 /proc/1763/fd/36 -> /db/live/pg_xlog/0000000000000000 (deleted) lrwx------ 1 postgres postgres 64 Apr 22 21:20 /proc/1803/fd/26 -> /db/live/pg_xlog/0000000000000000 (deleted) lrwx------ 1 postgres postgres 64 Apr 22 21:20 /proc/3241/fd/36 -> /db/live/pg_xlog/0000000000000000 (deleted) TIA Francis Reader ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Imerge Limited Tel :- +44 (0)1954 783600 Unit 6 Bar Hill Business Park Fax :- +44 (0)1954 783601 Saxon Way Web :- http://www.imerge.co.uk Bar Hill Cambridge CB3 8SL United Kingdom ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html
