Re: Couple of issues with pg_xlogdump - Mailing list pgsql-hackers

From Pavan Deolasee
Subject Re: Couple of issues with pg_xlogdump
Date
Msg-id CABOikdMnOpwb0FYhjYxSZx1Q0TJj25=yYH_=PaRmCN1XMAkbTw@mail.gmail.com
Whole thread Raw
In response to Re: Couple of issues with pg_xlogdump  (Andres Freund <andres@2ndquadrant.com>)
Responses Re: Couple of issues with pg_xlogdump
List pgsql-hackers



On Tue, Apr 23, 2013 at 3:00 PM, Andres Freund <andres@2ndquadrant.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

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