Re: MVCC catalog access

On 2013-05-22 22:51:13 -0400, Robert Haas wrote:
> In discussions today, Tom Lane suggested testing the time to start up
> a backend and run a simple query such as "SELECT 2+2" in the absence
> of a relcache file.

> I did this and can't measure any overhead as a result of MVCC catalog
> access.  I tried it with no active connections.  I tried it with 600
> idle active connections (to make taking MVCC snapshots more
> expensive).

Did you try it with the 600 transactions actually being in a transaction
and having acquired a snapshot?


> All in all, I'm still feeling optimistic.

+1. I still feel like this has to be much harder since we made it out to
be hard for a long time ;)

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services