Re: On-demand running query plans using auto_explain and signals - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: On-demand running query plans using auto_explain and signals
Date
Msg-id CAFj8pRAk7EiGO9-GDR5rK7rDh76okyYKP5kDAOMHaRyJ_XCvsw@mail.gmail.com
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In response to Re: On-demand running query plans using auto_explain and signals  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: On-demand running query plans using auto_explain and signals  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers


2015-09-17 14:06 GMT+02:00 Robert Haas <robertmhaas@gmail.com>:
On Tue, Sep 15, 2015 at 5:00 AM, Shulgin, Oleksandr
<oleksandr.shulgin@zalando.de> wrote:
> Please see attached for implementation of this approach.  The most
> surprising thing is that it actually works :)

It's cool to see these interesting ideas for using some of the code
I've been working on for the last couple of years.  However, it seems
to me that a better design would avoid the use of shm_mq.  Instead of
having the guy who asks the question create a DSM, have the guy who
sends back the answer create it.  Then, he can just make the DSM big
enough to store the entire string.  I think that's going to be a lot
more robust than what you have here.

Please, can you explain what is wrong on using of shm_mq? It works pretty well now.

There can be a contra argument, why don't use shm_mq, because it does data exchange between processes and this patch introduce new pattern for same thing.

Regards

Pavel
 

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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