Обсуждение: pqReadData() -- backend closed the channel unexpectedly.

I have a bit of an odd problem with an update statement. I have a table
logs2 at 35 columns wide and a miserly 193 rows. I also have a table
testtime at 4 columns wide and 2.2 million rows. When I run the following
sql I get a success on testtime and a failure of "pqReadData() -- backend
closed the channel unexpectedly on logs2".

update <either tablename> set time2 = to_timestamp(time, 'HH24:MI:SS');

This is quite confusing to me, I have a success on updating a 2.2 million
row table and a failure on a 193 row table (the smaller data set is a subset
of the 2.2 million row selection). Both tables are fresh, built with a
select into statement, a variety of other queries work fine with these
tables. The machine has a gig of ram and a 800mb shared buffer. The sort
buffer set to 16mb.

What is causing this problem? How can I figure this out?

I have some theories on what might be going wrong. The sort buffers are
probably too small (I am working on getting my hands on the root password so
I can play with this). There is some problem with version 7.0.3 that is
causing the back end to drop out, but I have seen no postings on that
possibility.

So any advice on how to trace this problem down would be great.

-Jeff Barrett

"Jeff Barrett" <jbarrett@familynetwork.com> writes:
> I get a success on testtime and a failure of "pqReadData() -- backend
> closed the channel unexpectedly on logs2".

> update <either tablename> set time2 = to_timestamp(time, 'HH24:MI:SS');

Any NULL values in the time column?  ISTR to_timestamp fails on NULLs in
pre-7.1 releases.  Try upgrading.

            regards, tom lane

Checked that out, every row has a value and the values are properly
formatted. Seems like this may be an issue of not enough ram in the server.
The only problem I have with that diagnosis is that I do not get an out of
memory error, I just loose the back end.

Thanks,

Jeff

"Tom Lane" <tgl@sss.pgh.pa.us> wrote in message
news:12678.991063302@sss.pgh.pa.us...
> "Jeff Barrett" <jbarrett@familynetwork.com> writes:
> > I get a success on testtime and a failure of "pqReadData() -- backend
> > closed the channel unexpectedly on logs2".
>
> > update <either tablename> set time2 = to_timestamp(time, 'HH24:MI:SS');
>
> Any NULL values in the time column?  ISTR to_timestamp fails on NULLs in
> pre-7.1 releases.  Try upgrading.
>
> regards, tom lane
>
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"Jeff Barrett" <jbarrett@familynetwork.com> writes:
> Checked that out, every row has a value and the values are properly
> formatted. Seems like this may be an issue of not enough ram in the server.

If it's a memory leak issue, my advice is still to upgrade to 7.1.

            regards, tom lane