From: Tom Lane <tgl@sss.pgh.pa.us>
To: "David G. Johnston" <david.g.johnston@gmail.com>
cc: Shaozhong SHI <shishaozhong@gmail.com>,
        pgsql-sql <pgsql-sql@lists.postgresql.org>
Subject: Re: Can we set time exception?
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Comments: In-reply-to "David G. Johnston" <david.g.johnston@gmail.com>
	message dated "Thu, 13 Jul 2023 08:36:48 -0700"
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Date: Thu, 13 Jul 2023 11:52:32 -0400
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"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Thu, Jul 13, 2023 at 7:46 AM Shaozhong SHI <shishaozhong@gmail.com>
> wrote:
>> Can we set a time exception?
>> If the function responds with result in a given time, we take the result.
>> If the response of the function exceeds the time set, skip it.

> No.  Function execution happens on a single thread (i.e., synchronous) in a
> stacked manner.  There is no way for the caller to get processing control
> back other than the callee returning.

You could do something with statement_timeout, but the recovery would
have to be managed on the client (application) side.  IIRC we measure
that as the total time to finish a client query, not the time of any
one statement within a function or DO block.

			regards, tom lane