Re: PostgreSQL Server Crash using plPHP or PL/Perl

Thanks for the tips.  I will try to use the strict pragma as you suggested
and see if it helps.

The code runs fine most of the time.  The issue is as time elapses, the
server ends up crashing.  Generally, it will crash within a day of use
(with only 3 clients hitting it).  The reason we believe it is the triggers
is that once we remove the triggers, the server works fine for weeks and
months with no problems.  Once we re-enable the triggers, the server
crashes within 1 day.

Yes, we have seen quickly the code is very costly to execute, especially on
queries that update many rows.  We have this home-grown solution because we
need the ability to have two sites have their own copy of the data to
improve performance.  We tried to access data over T1 lines, but it was too
slow, and we would prefer not to be out of service if the T1 is down.

Thanks for your quick response and assistance.


Thank you,
Carl M. Nasal II
BMA Enterprises, Inc.


Agent M wrote:
> Are you certain that it is the trigger that is crashing the process? If
> that is true, then there may be a bug in plperl.
>
> To debug, you could use gdb, but try this first:
> Use the strict pragma. To do this in plperl (instead of plperlu), use:
>     BEGIN { strict->import(); }
>     or set strict mode to on in postgresql.conf [I don't understand why
> this isn't the default.]
>     You will need to declare all your variables using my $var. [You are
> already half-way there because you declare a lot of empty strings.]
>
> You already pepper your code with elog(NOTICE,"") so you can tell us how
> far the code gets right? You can use more elogs to hone in on the line
> that crashes.
>
> Are you aware that your code will be very costly to execute?
>
> On Jul 11, 2006, at 5:43 PM, Carl M. Nasal II wrote:
>
>> We are writing a multi-master replication process for our Electronic
>> Medical Records product.  We have written triggers in plPHP and then
>> in PL/Perl to keep an audit trail of the changes as well as flags so
>> the data can be replicated.  We started with plPHP, but then server
>> started crashing, which reset all connections to the database
>> (requiring our application to be restarted).  We then tried to rewrite
>> the code using PL/Perl, but the same problem has occurred.  The code
>> for the triggers are available at:
>>
>> http://medical.bmaenterprises.com/audit.plphp
>> http://medical.bmaenterprises.com/audit.plperl
>>
>> We create the triggers by running the follow SQL statement for each
>> table:
>>
>> CREATE TRIGGER config_audit AFTER INSERT OR UPDATE OR DELETE ON config
>> FOR EACH ROW EXECUTE PROCEDURE audit();
>>
>> Any ideas of what is causing the server to crash will be helpful.
>>
>> Below are the lines from the PostgreSQL serverlog file when the crash
>> occurs:
>> ----------------------------------------------------------------------------
>>
>> LOG:  server process (PID 29153) exited with exit code 255
>> LOG:  terminating any other active server processes
>> WARNING:  terminating connection because of crash of another server
>> process
>> DETAIL:  The postmaster has commanded this server process to roll back
>> the current transaction and exit, because another server process exited
>> HINT:  In a moment you should be able to reconnect to the database and
>> repeat your command.
>> LOG:  all server processes terminated; reinitializing
>> LOG:  database system was interrupted at 2006-07-11 16:01:32 EDT
>> LOG:  checkpoint record is at 1/F413F26C
>> LOG:  redo record is at 1/F413F26C; undo record is at 0/0; shutdown FALSE
>> LOG:  next transaction ID: 7628670; next OID: 693120
>> LOG:  next MultiXactId: 1; next MultiXactOffset: 0
>> LOG:  database system was not properly shut down; automatic recovery
>> in progress
>> LOG:  redo starts at 1/F413F2B0
>> LOG:  record with zero length at 1/F4186D3C
>> LOG:  redo done at 1/F4186D14
>> LOG:  database system is ready
>> LOG:  transaction ID wrap limit is 2147484146, limited by database
>> "postgres"
>>
>>
>> Thank you,
>> Carl M. Nasal II
>> BMA Enterprises, Inc.
>>
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