Re: Couple of issues with pg_xlogdump

On Tue, Apr 23, 2013 at 3:00 PM, Andres Freund <andres(at)2ndquadrant(dot)com>wrote:

> On 2013-04-23 14:51:05 +0530, Pavan Deolasee wrote:
> > Hello,
> >
> > I was playing with pg_xlogdump in the HEAD and found a few issues.
> >
> > 1. Tried compiling pg_xlogdump via PGXS mechanism and it fails with the
> > following error:
> > make: *** No rule to make target
> >
> `/home/pavan.deolasee/work/pgsql/postgresql/install/lib/pgxs/src/makefiles/../../src/backend/access/transam/xlogreader.c',
> > needed by `xlogreader.c'. Stop.
> >
> > There are no issues if the sources are compiled directly inside the
> contrib
> > module
>
> Yes, its not supposed to work. In some previous thread I was suggesting
> to write out an explicit error but the reactions where mixed, so I
> didn't pursue it further. I guess I should submit something more than a
> POC patch then...
>
>
Yeah, I think we can print a user friendly error if USE_PGXS is set. Or at
least remove its handling from the Makefile

>
> Which this confirms. This is likely the current end of wal. If you look
> at pg_current_xlog_location() after starting the server again, it should
> show an address nearby?
>
>
Oh yes, you are right. Again, could there be a better way to report empty
WAL files ? A general tendency would be to look at the last few WAL files
in case failures or crashes and they are likely to be empty.

>
>
> It works without either if you use explicit options like -s STARTADDR
> and -p PATH which is frequently useful to just print a few records at
> the correct point. I am not sure how could put that in there without
> making it too complicated. Any suggestions?
>
>
Ah ok. Can we mention these details at in the documentation ?
http://www.postgresql.org/docs/devel/static/pgxlogdump.html

Thanks,
Pavan

--
Pavan Deolasee
http://www.linkedin.com/in/pavandeolasee