Re: count(*) performance improvement ideas

PFC wrote:
> Let's try this quick & dirty implementation of a local 
> count-delta cache  
> using a local in-memory hashtable (ie. {}).

> CREATE OR REPLACE FUNCTION update_count( key TEXT, delta INTEGER )
>    RETURNS INTEGER
> AS $$
>      if key in GD:
>              GD[key] += delta
>      else:
>              GD[key] = delta
>      return GD[key]
> $$ LANGUAGE plpythonu;

Thanks for the code, this seems to be very much what I was looking for.

I don't know plpythonu (nor python), just read a few docs now:
"The global dictionary SD is available to store data between function calls. This variable is private static data. The global dictionary GD is public data, available to all Python functions within a session. Use with care."

Does session == transaction or connection?
I don't understand the difference between SD and GD, private and public. Where are the context boundaries?

Regards,
Stephen Denne.

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