Re: Bug #929: Client connection to postgresql hangs indefi

Started by Claudio Natoliabout 23 years ago3 messagesbugs
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#1Claudio Natoli
claudio.natoli@memetrics.com

where test.sql is a file composed of many, many thousands

of the following pair of statements:

create table dud_table (f integer);
drop table dud_table;
Invariably, after some period of time, the second

connection (B) will

hang.

It would help if you would quantify how many create/drop
pairs it takes.

[Lots. Ok, I know that doesn't help. =]

The thing is, it happens occasionally. The more statements you throw at it,
the more likely it is to hang before completing the file...

As an attempt at quantification, I'll say this. We are currently using a
test file with about 5000 pairs of create/drop. It (almost?) never makes it
through a pass of this file. Your mileage may vary.

Note: Problem may be limited to Windows installation (cygipc?); have
reproduced on "virgin" Win2K; have not been able to reproduce under
Linux

If you've tried and failed to reproduce on Linux then the most likely
bet is that it's a Cygwin bug. But it would be good to try on some
other Unixoid platforms before pointing a finger in that direction.

Absolutely. Certainly possible to imagine some form of race condition in
cygipc being responsible, but I'm only guessing from the symptoms (not from
any knowledge of the implementation of either postgres or cygwin/ipc).

Cheers,
Claudio

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#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Claudio Natoli (#1)
Re: Bug #929: Client connection to postgresql hangs indefi nitely (under possibly pathological scenarios)

Claudio Natoli <claudio.natoli@memetrics.com> writes:

As an attempt at quantification, I'll say this. We are currently using a
test file with about 5000 pairs of create/drop. It (almost?) never makes it
through a pass of this file. Your mileage may vary.

FWIW, I ran 10000 create/drop pairs through 7.3.2 (well, actually REL7_3
branch tip, but I'll be *real* surprised if it differs on this point)
on HPUX 10.20. No sign of a problem.

You did say you tried already on Linux, right? Which version exactly?

Can someone try the experiment on some *BSD platform? Three data points
would make me reasonably comfortable that it doesn't fail on Unixen, and
then I'll say Cygwin gets the blame...

regards, tom lane

#3Claudio Natoli
claudio.natoli@memetrics.com
In reply to: Claudio Natoli (#1)

You did say you tried already on Linux, right? Which version exactly?

Red Hat Linux release 7.2 (Enigma)
Kernel 2.4.7-10

Can someone try the experiment on some *BSD platform? Three
data points would make me reasonably comfortable that it doesn't fail on
Unixen, and then I'll say Cygwin gets the blame...

Sounds reasonable. I'd also like to get confirmation from another cygwin
user too... any takers?

Cheers,
Claudio

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