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

From Andres Freund
Subject Re: Couple of issues with pg_xlogdump
Date
Msg-id 20130423160548.GF8499@alap2.anarazel.de
Whole thread Raw
In response to Re: Couple of issues with pg_xlogdump  (Alvaro Herrera <alvherre@2ndquadrant.com>)
List pgsql-hackers
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
insidefile \"%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/PostgreSQL Development, 24x7 Support, Training &
Services



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