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chr() function leads to OOM / killed connection with 8.1, 8.2

From: Wiktor Wodecki <wiktor(dot)wodecki(at)Net-m(dot)de>
To: pgsql-bugs(at)postgresql(dot)org
Subject: chr() function leads to OOM / killed connection with 8.1, 8.2
Date: 2007-07-19 16:16:25
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Lists: pgsql-bugs
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I found something that I believe to be a bug in postgresql handling of
the chr function. This function takes an ascii code and returns the
Now it seems that a value greater than 191 seems to cause trouble with a
backend instance of postgresql. I verified this on postgres 8.1.8, 8.1.9
and 8.2.4. I could not trigger the behaviour with 8.1.3 or 8.1.5. I did
not test other versions.

The effects are:

8.1.8 / 8.1.9:
transport=> select id,msisdn,replace(msisdn, chr(192), 'FF') from
msisdnmap limit 2;
ERROR:  out of memory
DETAIL:  Failed on request of size 17.

The backend process consumes a lot memory and uses up all available CPU
 cycles. The logfile gives OOM statistics. I can provide that if needed.

dwh=> select replace(customer_id, chr(192), 'FF') from sms_customer limit 1;
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.

the logfile says:

2007-07-19 18:07:49 CEST @[5385]LOG:  server process (PID 15351) was
terminated by signal 11
2007-07-19 18:07:49 CEST @[5385]LOG:  terminating any other active
server processes
2007-07-19 18:07:49 CEST dwh(at)dwh[15352]FATAL:  the database system is in
recovery mode
2007-07-19 18:07:49 CEST @[5385]LOG:  all server processes terminated;
2007-07-19 18:07:49 CEST @[15353]LOG:  database system was interrupted
at 2007-07-19 12:29:33 CEST
2007-07-19 18:07:49 CEST @[15353]LOG:  checkpoint record is at 9/6552A6C0
2007-07-19 18:07:49 CEST @[15353]LOG:  redo record is at 9/6552A6C0;
undo record is at 0/0; shutdown TRUE
2007-07-19 18:07:49 CEST @[15353]LOG:  next transaction ID: 0/2581; next
OID: 24576
2007-07-19 18:07:49 CEST @[15353]LOG:  next MultiXactId: 1; next
MultiXactOffset: 0
2007-07-19 18:07:49 CEST @[15353]LOG:  database system was not properly
shut down; automatic recovery in progress
2007-07-19 18:07:50 CEST @[15353]LOG:  record with zero length at 9/6552A708
2007-07-19 18:07:50 CEST @[15353]LOG:  redo is not required
2007-07-19 18:07:50 CEST @[15353]LOG:  database system is ready

This behavior is independent of column type, so it should be easy to

Please verify that this is indeed a bug and not a mistake on our side.
Thank you.

- --

 Wiktor Wodecki

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Subject: Re: chr() function leads to OOM / killed connection with 8.1, 8.2
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