Re: recovery test failures on hoverfly - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: recovery test failures on hoverfly
Date
Msg-id befdb97b-f8e5-3fea-4ee6-c5d4c94f862c@dunslane.net
Whole thread Raw
In response to Re: recovery test failures on hoverfly  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: recovery test failures on hoverfly
List pgsql-hackers
On 6/12/21 5:28 PM, Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
>> I'm a bit dubious about this. It doesn't seem more robust to insist that
>> we pass undef in certain cases.
> True, it'd be nicer if that didn't matter; mainly because people
> will get it wrong in future.


Right, that's what I'm worried about.


>
>> If passing the SQL via stdin is fragile,
>> as we also found to be the case with passing it via the command line,
>> perhaps we should try passing it via a tmp file. Then there would
>> presumably be no SIGPIPE.
> Seems kind of inefficient.  Maybe writing and reading a file would
> be a negligible cost compared to everything else involved, but
> I'm not sure.


Well, in poll_query_until we would of course set up the file outside the
loop. I suspect the cost would in fact be negligible.


Note, too that the psql and safe_psql methods also pass the query via stdin.


>
> Another angle is that the SIGPIPE complaints aren't necessarily
> a bad thing: if psql doesn't read what we send, it's good to
> know about that.  IMO the real problem is that the errors are
> so darn nonrepeatable.  I wonder if there is a way to make them
> more reproducible?
>
>             


I don't know.


cheers


andrew


--
Andrew Dunstan
EDB: https://www.enterprisedb.com




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