Re: 8.4 -> 9.1 : ANALYSE VERBOSE; -> out of shared memory

Le 12/05/2014 16:24, Tom Lane a écrit :
> Souquieres Adam <adam(dot)souquieres(at)axege(dot)com> writes:
>> When i relaunch my ANALYSE VERBOSE, pg_locks table grows quickly from 20
>> lines to more than 1000 lines and still growing, all the lines are owned
>> by the same "virtual transaction" and the same "pid".
> Hm. I experimented a bit and looked at the code, and I find I was not
> remembering ANALYZE's behavior exactly right: it only processes all the
> tables inside one transaction if you start it inside a transaction block
> (ie, after BEGIN, or inside a function). If you just run it by itself
> then it does a transaction per table, just like VACUUM. So I'm thinking
> there's something you're not telling us about exactly how you invoke
> ANALYZE.

Ok, thank you for your help, we finally undestood what the problem is
with your hints.

In our production environment, which is "living", we have 4200 tables
(97% are generated by our program for BI performance) and not only 500 (
the real ones) ... this is the difference between test env and prod env,

moreover we launch the analyse verbose using JDBC with an ORM, and i
think it add begin; and end;.

I just tested it on pgadmin,

* without begin end, there is not so much lock,
* with begin end, there is a lock explosion that is normal when we
look at the number of tables involved.

The solution must be to define a *better strategy for tables
statistics*... we dont really need stats on all the tables because the
most part of them is static...

Thank you very much....

Regards,

Adam

>> When i finish to write this email, i juste hit more than 3200 lock owned
>> by the same transaction !
> Could you show us some of those locks (a few dozen lines from pg_locks)?
>
> regards, tom lane