On Sat, 15 Apr 2006, Tom Lane wrote:
Bruce Momjian <pgman@candle.pha.pa.us> writes:
Also, what happens if the log switch happens, and some data change is
written to the new WAL file in the first second, but nothing happens to
the database after that for a minute? Your test would still show the
old log file.
You seem to be assuming that ls will sort on the basis of the truncated
mtime that it displays, which is not the actual behavior of ls AFAIK.
I believe you're correct, at least with the ls I have here on my linux system.
I created two files quickly with touch. Here is the stat output:
File: `AA'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 802h/2050d Inode: 2736263 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 26/postgres) Gid: ( 26/postgres)
Access: 2006-04-15 11:02:46.000000000 -0700
Modify: 2006-04-15 11:02:46.000000000 -0700
Change: 2006-04-15 11:02:46.000000000 -0700
File: `AB'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 802h/2050d Inode: 2736264 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 26/postgres) Gid: ( 26/postgres)
Access: 2006-04-15 11:02:48.000000000 -0700
Modify: 2006-04-15 11:02:48.000000000 -0700
Change: 2006-04-15 11:02:48.000000000 -0700
ls -t | head -1
AB
So it looks like the original was correct all along, but with Tom's regex it's
much cleaner. Too bad grep's regex engine doesn't support {24}.
I'll change all my scripts to use the following:
ls -t /pg_xlog/ | grep
'^[0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F][0-9A-F]$'
| head -1
Thanks Tom!
--
Jeff Frost, Owner <[EMAIL PROTECTED]>
Frost Consulting, LLC http://www.frostconsultingllc.com/
Phone: 650-780-7908 FAX: 650-649-1954
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