Re: executeQuery and busy waiting

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От Dave Cramer
Тема Re: executeQuery and busy waiting
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Msg-id 1056810176.3271.3.camel@localhost.localdomain
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Ответ на Re: executeQuery and busy waiting  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-jdbc
tom,

I don't think this is the case here, he is doing a select from his own
user defined function, the funciont is emitting the notices, jdbc would
be spinning on reading the notices.

Dave
On Sat, 2003-06-28 at 01:46, Tom Lane wrote:
> Garrick Dasbach <Garrick@musicrebellion.com> writes:
> > Well, we found the problem.  Using a Packet Sniffer we found that
> > Postgres was sending Thousands of 8K messages back to our JDBC test
> > Program.  Inside these packets were the text from the 'NOTICE' commands
> > we were using to debug our function.  We didn't realize that Postgres
> > sent these messages back.
>
> Someone reported a comparable problem recently in libpq: they had an ON
> INSERT trigger that emitted tons of NOTICEs, and they found that a COPY
> into that table would hang up, because libpq's routines to process COPY
> IN data transmission don't bother to look to see if there's any return
> data they ought to read.  Sooner or later the return path fills up and
> the kernel blocks the sender (ie, the backend).  This is on my to-fix
> list, but I've not gotten to it yet.  It sounds like JDBC has a similar
> issue someplace.
>
>             regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
>       joining column's datatypes do not match
>
--
Dave Cramer <Dave@micro-automation.net>


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