Re: Couple of issues with pg_xlogdump

On 2013-04-23 11:51:06 -0300, Alvaro Herrera wrote:
> Andres Freund escribió:
> > On 2013-04-23 15:16:05 +0530, Pavan Deolasee wrote:
>
> > > > 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
> >
> > So something like:
> > At least one of STARTSEG, --start and --path or --rmgr=list has to be
> > specified.
>
> I think we need more than one synopsis line. Maybe
>
> Usage:
> pg_xlogdump [OPTION] --path=PATH --start=STARTPOS
> pg_xlogdump [OPTION] [STARTSEG [ENDSEG]]
>
> And then, under "options", do not list --path and --start (because
> that'd imply they can be used when STARTSEG is specified, which I
> understand they cannot).

Both can be used. If you specify --start and STARTSEG the address has to
be contained in the file:

if (XLogRecPtrIsInvalid(private.startptr))
XLogSegNoOffsetToRecPtr(segno, 0, private.startptr);
else if (!XLByteInSeg(private.startptr, segno))
{
fprintf(stderr,
"%s: start log position %X/%X is not inside file \"%s\"\n",
progname,
(uint32) (private.startptr >> 32),
(uint32) private.startptr,
fname);
goto bad_argument;
}

--path and STARTSEG/ENDSEG also makes sense, it will be used to locate
the file.

> Do we have any other possible operation mode? IIRC those are the only
> two possible modes.

I think so as well.

Greetings,

Andres Freund

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