Re: Info about concurrent sequential scans

Daniele Varrazzo wrote:
> Hello,
>
> at Prato PgDay in 2007 I remember hearing in a speech about a (then
> yet to come) "seqscan piggyback" feature, allowing concurrent
> sequential scans to use the same disk reads. I've now googled for info
> about this feature, but I found nothing conclusive (e.g. [1], [2] -
> which I don't know where is linked).
>
> So I'd like to know:
>
> is this feature currently implemented (I'm specifically interested in PG 8.3)?
> Is there any prerequisite needed to benefit from it (config setting,
> query characteristic, etc.)?
> Is there any feedback showing the feature kicking in (e.g. an explain
> analyze output, log, etc.)?

The feature is called 'synchronize_seqscans' and was implemented in
Postgres 8.3.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
PG East: http://www.enterprisedb.com/community/nav-pg-east-2010.do
+ If your life is a hard drive, Christ can be your backup. +