Re: Statement timeout behavior in extended queries

From: Tatsuo Ishii <ishii(at)sraoss(dot)co(dot)jp>
To: tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com
Cc: ishii(at)sraoss(dot)co(dot)jp, david(at)fetter(dot)org, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Statement timeout behavior in extended queries
Date: 2017-04-04 03:26:58
Message-ID: 20170404.122658.472182550318329721.t-ishii@sraoss.co.jp
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> Where is the statement_timeout timer stopped when processing Parse and Bind messages?

Actually the statement timer is replaced with new statement timer
value in enable_statement_timeout().

> Do you mean the following sequence of operations are performed in this patch?
>
> Parse(statement1)
> start timer
> stop timer
> Bind(statement1, portal1)
> start timer
> stop timer
> Execute(portal1)
> start timer
> stop timer
> Sync

Yes.

> It looks like the patch does the following. I think this is desirable, because starting and stopping the timer for each message may be costly as Tom said.
> Parse(statement1)
> start timer
> Bind(statement1, portal1)
> Execute(portal1)
> stop timer
> Sync

This doesn't work in general use cases. Following pattern appears
frequently in applications.

Parse(statement1)
Bind(statement1, portal1)
Execute(portal1)
Bind(statement1, portal1)
Execute(portal1)
:
:
Sync

Also what would happen if client just send a parse message and does
nothing after that?

So I think following is better:

Parse(statement1)
Bind(statement1, portal1)
Execute(portal1)
start timer
stop timer
Bind(statement1, portal1)
Execute(portal1)
start timer
stop timer
:
:
Sync

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

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