[Pgpool-general] pgpool limitations

[Gurjeet Singh]

On Thu, Aug 4, 2011 at 5:51 PM, Guillaume Lelarge <guillaume at lelarge.info>wrote:

> On Sat, 2011-07-30 at 08:38 +0900, Tatsuo Ishii wrote:
> > > On Thu, Jul 28, 2011 at 10:40 PM, Tatsuo Ishii <ishii at sraoss.co.jp>
> wrote:
> > >
> > >> >> Because newly added node is likely to have out of sync databases.
> Thus
> > >> >> bringing it online immediately will allow user to use obsolete
> > >> >> databases. You should do online recovery first.
> > >> >>
> > >> >
> > >> > Since the new slave being added is configured using streaming
> > >> replication,
> > >> > it is lagging behind the master just as much as any other currently
> > >> > configured slave. So from that standpoint the new slave should be
> allowed
> > >> to
> > >> > serve queries.
> > >>
> > >> It will be possible with pgpool-II 3.1 (without resetting existing
> > >> connections).
> > >>
> > >
> > > Is there something in the works to enable this, or is this feature
> still in
> > > design phase? If it is already being/been developed, I wish to know if
> this
> > > can be back-patched to a point release of pgpool 3.0.x.
> >
> > It has been already in pgpool-II 3.1 alpha version.
> > Currently there's no plan to back-patching to 3.0.x.
>
> I certainly hope we won't backpatch a new feature. That would be insane.
>

I don't consider this a new feature. I'd say this is unexpected side-effect
(a.k.a bug) of pcp_attach_node, since nowhere in the docs does is say that
invoking pcp_attach_node would drop all client connections.

Regards,
-- 
Gurjeet Singh
EnterpriseDB Corporation
The Enterprise PostgreSQL Company
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