>> Can pre-allocation go that further? for example, assuming >> 000000010000000E00000080 is currently being used, then is it possible >> that a segment named/numbered 00000001000000100000007E (which does >> exist in his pg_xlog as he reported in pgsql-admin thread) is >> pre-allocated already? > > Yes, if it's so old that it's no longer required for the crash recovery. > > WAL recycling is performed by checkpoint. Checkpoint always checks > whether there are > WAL files no longer required for crash recovery, IOW, WAL files which > were generated > before the prior checkpoint happened, and then if they are found, > checkpoint tries to recycle > them. >
Okay, now I understand. Also, looking at his "ls -l pg_xlog", I could find that modified timestamps of all those pre-allocated segments are about similar (around 12:10), whereas the latest modified time (15:37) is of segment 000000010000000E000000A7. Wonder if whatever configuration he is using is sub-optimal that these many WAL segments can be re-cycled upon a checkpoint? Or is this okay? -- Amit Langote -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
