Re: [PATCH 3/8] Add support for a generic wal reading facility dubbed XLogReader

On Monday, September 17, 2012 12:55:47 PM Heikki Linnakangas wrote:
> On 17.09.2012 13:01, Andres Freund wrote:
> > On Monday, September 17, 2012 11:07:28 AM Andres Freund wrote:
> >> On Monday, September 17, 2012 10:30:35 AM Heikki Linnakangas wrote:
> >>> On 17.09.2012 11:12, Andres Freund wrote:
> >>>> On Monday, September 17, 2012 09:40:17 AM Heikki Linnakangas wrote:
> >>>> If you don't want the capability to forward/filter the data and read
> >>>> partial data without regard for record constraints/buffering your
> >>>> patch seems to be quite a good start. It misses xlogreader.h
> >>>> though...
> >>>
> >>> Ah sorry, patch with xlogreader.h attached.
> >>
> >> Will look at it in a second.
> >
> > It seems we would need one additional callback for both approaches like:
> >
> > ->error(severity, format, ...)
> >
> > For both to avoid having to draw in elog.c.
>
> Yeah. Another approach would be to return the error string from
> ReadRecord. The caller could then do whatever it pleases with it, like
> ereport() it to the log or PANIC. I think I'd like that better.
That seems a bit more complex from a memory management perspective as you
probably would have to sprintf() into some buffer. We cannot rely on a backend
environment with memory contexts around et al...

Greetings,

Andres
--
Andres Freund http://www.2ndQuadrant.com/
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