Re: plperlu stored procedure seems to freeze for a minute

On 2015-12-01 13:13:27 -0500, Tom Lane wrote:
> "Peter J. Holzer" <hjp-pgsql@hjp.at> writes:
> > Postgres worker processes are single-threaded, are they? Is there
> > something else which could interact badly with a moderately complex
> > multithreaded I/O library used from a stored procedure?
>
> Yes, lots.  If you cause additional threads to appear inside a backend
> process, things could break arbitrarily badly.  It's up to you to ensure
> that none of those extra threads ever escape to execute any non-Perl
> code.

Actually, non-�MQ code. Perl doesn't like to be unexpectedly
multithreaded either. Yes, those threads should only ever execute code
from the �MQ library. In fact they are automatically created and
destroyed by the library and there is no way to control them from Perl
code (there may be a way to do that from the C API, but I don't remember
seeing that in the manual).

> I suspect this could easily explain the problems you're seeing.

Quite.

    hp

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