Re: Statement timeout behavior in extended queries - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Statement timeout behavior in extended queries
Date
Msg-id 20170404233853.mwj6li7mirjb6mep@alap3.anarazel.de
Whole thread Raw
In response to Re: Statement timeout behavior in extended queries  (Tatsuo Ishii <ishii@sraoss.co.jp>)
Responses Re: Statement timeout behavior in extended queries  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
On 2017-04-04 16:10:32 +0900, Tatsuo Ishii wrote:
> >> If what Tatsuo-san said to Tom is correct (i.e. each Parse/Bind/Execute starts and stops the timer), then it's a
concernand the patch should not be ready for committer.  However, the current patch is not like that -- it seems to do
whatothers in this thread are expecting.
 
> > 
> > Oh, interesting - I kind of took the author's statement as, uh,
> > authoritative ;).  A quick look over the patch confirms your
> > understanding.
> 
> Yes, Tsunakawa-san is correct. Sorry for confusion.
> 
> > I think the code needs a few clarifying comments around this, but
> > otherwise seems good.  Not restarting the timeout in those cases
> > obviously isn't entirely "perfect"/"correct", but a tradeoff - the
> > comments should note that.
> > 
> > Tatsuo-san, do you want to change those, and push?  I can otherwise.
> 
> Andres,
> 
> If you don't mind, could you please fix the comments and push it.

Hm. I started to edit it, but I'm halfway coming back to my previous
view that this isn't necessarily ready.

If a client were to to prepare a large number of prepared statements
(i.e. a lot of parse messages), this'll only start the timeout once, at
the first statement sent.  It's not an issue for libpq which sends a
sync message after each PQprepare, nor does it look to be an issue for
pgjdbc based on a quick look.

Does anybody think there might be a driver out there that sends a bunch
of 'parse' messages, without syncs?

- Andres



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