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Thread: backend closed the channel unexpectedly

backend closed the channel unexpectedly

From
David Wetzel
Date:
Hi,

I have found a bug that is very easy to reprouduce here:

The table is created with this code:

create table DIAGNOSE (ART varchar(1) NOT NULL, AUFENTHALTNR int NOT NULL,
CREATION_DATE datetime, CREATION_USER varchar(30), DAUERDIAGNOSENR int NOT
NULL, MODIFICATION_DATE datetime, MODIFICATION_USER varchar(30), NR int NOT
NULL, OPNR int, TEXT varchar(250) NOT NULL, VERWEILDAUER int, ZEIT datetime);

CREATE UNIQUE INDEX DIAGNOSE_NR ON DIAGNOSE (NR);

Then create a file that contains 100 000 times this line and save it as
/tmp/DBTEST.sql:

INSERT INTO  DIAGNOSE (CREATION_DATE, CREATION_USER, VERWEILDAUER, ART,
TEXT, AUFENTHALTNR, NR, OPNR, DAUERDIAGNOSENR, MODIFICATION_USER,
MODIFICATION_DATE, ZEIT)  VALUES  ('Fri May 07 21:10:52 1999 CEST', 'USER',
NULL, 'X', 'Noch nicht eingegeben', 71108, 316707, NULL, 0, 'USER', 'Fri May
07 21:10:52 1999 CEST', 'Fri May 07 21:10:52 1999 CEST');


Then do

psql -q -f /tmp/DBTEST.sql mydb

Wait.

The error messages are ok. But not the closing of the backend!

Is this bug known? Are there any patches out? I use postgresql-6.4.2 on NetBSD.

NOTE: I have only subscribed pgsql-ports@postgreSQL.org

---
   _  _
 _(_)(_)_  David Wetzel, Turbocat's Development,
(_) __ (_) Buchhorster Strasse, D-16567 Muehlenbeck/Berlin, FRG,
  _/  \_   Fax +49 33056 82835 NeXTmail dave@turbocat.de
 (______)  http://www.turbocat.de/
           DEVELOPMENT * CONSULTING * ADMINISTRATION

Re: [HACKERS] backend closed the channel unexpectedly

From
Tom Lane
Date:
David Wetzel <dave@turbocat.de> writes:
> I have found a bug that is very easy to reprouduce here:

> [ backend crash after many attempts to insert same data into a
> uniquely-indexed table ]

This may be the same bug that was discussed earlier today on the hackers
list: the backend fails to release temporary memory after an error, so
if you make it generate enough error messages during one session you can
eventually run out of memory.  Watch the process with 'top' or some such
to see if it gets up to your system's limit on process size just before
failing.

I'm hoping to look into the cause of the memory leak shortly, but
no guarantees about how soon it might be fixed ;-).

            regards, tom lane

Re: [PORTS] Re: [HACKERS] backend closed the channel unexpectedly

From
David Wetzel
Date:
> From: Tom Lane <tgl@sss.pgh.pa.us>
> Sender: owner-pgsql-ports@postgreSQL.org
>
> David Wetzel <dave@turbocat.de> writes:
> > I have found a bug that is very easy to reprouduce here:
>
> > [ backend crash after many attempts to insert same data into a
> > uniquely-indexed table ]
>
> This may be the same bug that was discussed earlier today on the hackers

I cc'ed the mail to pgsql-hackers@postgreSQL.org, pgsql-ports@postgreSQL.org
But I only subscribe to pgsql-ports@postgreSQL.org.

(...)
> I'm hoping to look into the cause of the memory leak shortly, but
> no guarantees about how soon it might be fixed ;-).
>
>             regards, tom lane

Great. What we did as bugfix in our importer program is to close and reopen
the connection to the backend each 1000 rows. This is very ugly but seems to
work until someone with the backend-knowlege has fixed the bug.

First we thought that we made a mistake in our EOAdaptor*) for PSQL and
debugged that beast for many hours...

Dave

*) For EOF and WebObjects from Apple/NeXT see www.turbocat.de
   _  _
 _(_)(_)_  David Wetzel, Turbocat's Development,
(_) __ (_) Buchhorster Strasse, D-16567 Muehlenbeck/Berlin, FRG,
  _/  \_   Fax +49 33056 82835 NeXTmail dave@turbocat.de
 (______)  http://www.turbocat.de/
           DEVELOPMENT * CONSULTING * ADMINISTRATION