Re: Big 7.4 items

Shridhar Daithankar wrote:
> On Monday 16 December 2002 08:07 pm, you wrote:
> > On Mon, 2002-12-16 at 08:20, Shridhar Daithankar wrote:
> > > I don't know about WAL numbering but AFAIU, it increments and old files
> > > are removed once there are enough WAL files as specified in
> > > posgresql.conf. IIRC there are some perl based replication project exist
> > > already which use this feature.
> >
> > The problem with this is that most people, AFAICT, are going to size WAL
> > based on their performance/sizing requirements and not based on
> > theoretical estimates which someone might make to allow for a window of
> > failure. That is, I don't believe increasing the number of WAL's is
> > going to satisfactorily address the issue.
>
> Sorry for not being clear. When I said, WAL numbering, I meant WAL naming
> conventions where numbers are used to mark WAL files.
>
> It is not number of WAL files. It is entirely upto the installation and IIRC,
> even in replication project(Sorry I forgot the exact name), you can set
> number of WAL files that it can have.

Basically, PITR is going to have a way to archive off a log of database
changes, either from WAL or from somewhere else. At some point, there
is going to have to be administrative action which says, "I have a
master down for three days. I am going to have to save my PITR logs for
that period." So, PITR will probably be used for recovery of a failed
master, and such recover is going to have to require some administrative
action _if_ the automatic expiration of PITR logs is shorter than the
duration the master is down.

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