Re: Proposed doc-patch: Identifying the Current WAL file

[Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>]

Jeff Frost <jeff(at)frostconsultingllc(dot)com> writes:
>>> ls -tp /pg_xlog/ | grep -v "backup\|/" | head -1
>>
>> What does the -p and \| pipe check do?  We don't have named pipes in
>> that directory, do we?

> The -p shows forward slashes after directories and the \| acts as an or and 
> the / following that just lets us filter directories out.

This seems both overly cute and wrong, because it fails to filter plain
files that might have a new mtime but aren't WAL files.  I'd suggest a
simple test on file name to make sure it looks like a WAL file, ie,
24 hex digits.

	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

			regards, tom lane