WAL file question

Geoffrey <lists@serioustechnology.com> writes:

listing of wal file time stamps for one of our production databases:
Nov 17 06:22 000000010000006100000013
Nov 17 06:42 000000010000006100000014
Nov 17 07:02 000000010000006100000015
Nov 17 07:22 000000010000006100000016
Nov 17 07:42 000000010000006100000017
Nov 17 08:02 000000010000006100000018
Nov 17 08:22 000000010000006100000019
Nov 17 08:34 000000010000006100000012

I would expect that these things are sequential, yet the file that I
would think would be the oldest (000000010000006100000012) has the
latest time stamp.

What am I missing?

Most of those are probably old files that have been renamed into place
for future use --- and the renamer doesn't really worry about reusing
old files in order. I suspect ...12 is the only one that's live.
A look at pg_controldata output would help you check that.

regards, tom lane

Tom Lane wrote:

Geoffrey <lists@serioustechnology.com> writes:

listing of wal file time stamps for one of our production databases:
Nov 17 06:22 000000010000006100000013
Nov 17 06:42 000000010000006100000014
Nov 17 07:02 000000010000006100000015
Nov 17 07:22 000000010000006100000016
Nov 17 07:42 000000010000006100000017
Nov 17 08:02 000000010000006100000018
Nov 17 08:22 000000010000006100000019
Nov 17 08:34 000000010000006100000012

I would expect that these things are sequential, yet the file that I
would think would be the oldest (000000010000006100000012) has the
latest time stamp.

What am I missing?

Most of those are probably old files that have been renamed into place
for future use --- and the renamer doesn't really worry about reusing
old files in order. I suspect ...12 is the only one that's live.
A look at pg_controldata output would help you check that.

regards, tom lane

Thanks Tom.

--
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
- Benjamin Franklin