Re: BUG #10141: Server fails to send query result.

There is more details:

Even when it works it sends D more than once usually

=46rom backend> D
=46rom backend (#4)> 33170
=46rom backend> D
=46rom backend (#4)> 33170
=46rom backend> D
=46rom backend (#4)> 33170
=46rom backend> D
=46rom backend (#4)> 33170
=46rom backend> D
=46rom backend (#4)> 33170
=46rom backend (#2)> 2
=46rom backend (#4)> 33132
=46rom backend (33132)> =
\x01060000006c0000000103000000010000000a00000080ce26eb13eaa640003fad186435=
9840800c2b00bdeea6400055d
=46rom backend (#4)> 24
=46rom backend (24)> "landuse"=3D>"residential"

My query looks like
select * from poly9(3130860.6785608195, 7592337.1455099881, =
3209132.1955248402, 7670608.6624740083);

while poly9 is function generated by app before data processing starts. =
And basically it looks like:

CREATE FUNCTION "public"."poly9"(IN minx numeric, IN miny numeric, IN =
maxx numeric, IN maxy numeric)=20
returns table (geom_out bytea, tags_out public.hstore)=20
    AS $BODY$
declare
bbox =3D st_makebox2d(st_makepoint(minx, miny), st_makepoint(maxx, =
maxy));
begin
-- simplified version
return query
SELECT way, tags FROM planet_polygon WHERE way && bbox;=20
end;
$BODY$
    LANGUAGE plpgsql
    COST 100
    ROWS 1000
    CALLED ON NULL INPUT
    SECURITY INVOKER
    VOLATILE;

Hope it helps. This solution worked fine 2 months ago. Is there a small =
chance that something broken inside 9.3.4?

Best Regards,
Evgen Bodunov.

On Apr 25, 2014, at 10:20 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Stephen Frost <sfrost@snowman.net> writes:
>> * molind@gmail.com (molind@gmail.com) wrote:
>>> I added PQtrace for each thread and wait for stuck thread. There is =
trace:
>=20
>>> =46rom backend> D
>>> =46rom backend (#4)> 139891
>>> =46rom backend> D
>>> =46rom backend (#4)> 139891
>>> =46rom backend> D
>>> =46rom backend (#4)> 139891
>>> =46rom backend> D
>>> =46rom backend (#4)> 139891
>>> =46rom backend> D
>>> =46rom backend (#4)> 139891
>>> =46rom backend> D
>>> =46rom backend (#4)> 139891
>=20
> FWIW, this looks suspiciously like libpq is unable to consume data =
from
> its input buffer (and keeps retrying to process the same data).  Are =
you
> using PQsetnonblocking by any chance?  If so, this probably indicates
> failure to follow the required call sequencing to process data.
>=20
> Another likely theory, given that you mentioned multiple client =
threads,
> is that the threads are stomping on each others' toes somehow.  libpq
> does not defend itself against that: it's up to you to be sure that
> only one thread is touching each PGconn object.
>=20
>>> Seems problem somewhere inside PostgreSQL. It tries to send result =
but
>>> fails.
>=20
>> I don't see anything here which shows that to be the case.
>=20
> Indeed.  I'd bet considerable money that this is a client-side issue.
> It's possible that it's a libpq bug, but what seems more likely is
> that you're using libpq improperly.
>=20
>             regards, tom lane