Re: [External] Re: xmin and very high number of concurrent transactions

Thank you everyone for responding.
Appreciate your help.

Looks like I need to understand the concepts a little more in detail , to
be able to ask the right questions, but atleast now I can look at the
relevant docs.

On Wed, 13 Mar 2019 at 2:44 PM Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:

> On Wed, Mar 13, 2019 at 9:50 AM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
> wrote:
> >
> > Vijaykumar Jain wrote:
> > > I was asked this question in one of my demos, and it was interesting
> one.
> > >
> > > we update xmin for new inserts with the current txid.
> > > now in a very high concurrent scenario where there are more than 2000
> > > concurrent users trying to insert new data,
> > > will updating xmin value be a bottleneck?
> > >
> > > i know we should use pooling solutions to reduce concurrent
> > > connections but given we have enough resources to take care of
> > > spawning a new process for a new connection,
> >
> > You can read the function GetNewTransactionId in
> > src/backend/access/transam/varsup.c for details.
> >
> > Transaction ID creation is serialized with a "light-weight lock",
> > so it could potentially be a bottleneck.
>
> Also I think that GetSnapshotData() would be the major bottleneck way
> before GetNewTransactionId() becomes problematic. Especially with
> such a high number of active backends.
>
--

Regards,
Vijay