Re: count(*) performance improvement ideas - Mailing list pgsql-hackers

From Stephen Denne
Subject Re: count(*) performance improvement ideas
Date
Msg-id F0238EBA67824444BC1CB4700960CB48051D6243@dmpeints002.isotach.com
Whole thread Raw
In response to Re: count(*) performance improvement ideas  (PFC <lists@peufeu.com>)
Responses Re: count(*) performance improvement ideas  ("Stephen Denne" <Stephen.Denne@datamail.co.nz>)
List pgsql-hackers
PFC wrote
> <Stephen.Denne@datamail.co.nz> wrote:
> > I don't know plpythonu (nor python), just read a few docs now:
> 
>     Learn Python, it is a really useful language ;)

My wife has a snake phobia, besides, I've just started learning Scala.


>     There is no sharing between processes, so
>     - both SD and GD are limited to the current session 
> (connection, postgres  
> process), no shared memory is involved
>     - GD is global between all python functions (global)
>     - SD is specific to each python function (static)

Thanks.

>     The big gotcha is that these are all non-transactional 
> : if you rollback,  
> GD and SD stay the same, and when you issue a query, you can 
> assume the  
> state of SD and GD is random (due to previous queries) unless you  
> initialize them to a known value.

Using txid_current() as a key should alleviate that.

Regards,
Stephen Denne.

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