Re: [HACKERS] two records with same oid, freak accident?

From: Massimo Dal Zotto <dz(at)cs(dot)unitn(dot)it>
To: hackers(at)postgreSQL(dot)org (PostgreSQL Hackers)
Subject: Re: [HACKERS] two records with same oid, freak accident?
Date: 1998-07-18 15:32:32
Message-ID: 199807181532.RAA07614@pennac.cs.unitn.it
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>
>
> in some sort of freak accident, we've ended up with a duplicated
> record. all info, including the oid was duplicated.
>
> it was during an update, two people ran a command at the same time.
>
> user 1: BEGIN
> user 1: NOTIFY
> user 1: UPDATE
> user 2: BEGIN
> user 2: NOTIFY
> user 1: END
> user 2: UPDATE
> user 2: END
>
> same command, so the queries are the same. the record duplicated was
> the one being updated. i'll try to reproduce it.
>
> also, I had a unique index on the table, but that didn't seem to make
> any difference.
>
> any ideas on how to delete one without deleting both?
>

I have the same problem with pg_listeners. Sometimes I find duplicate records
with same oid in the table inserted by concurrent transactions. I suspect
that the problem is caused by the notify but I'm not sure. Could you post
some test commnds to reproduce the problem ?

--
Massimo Dal Zotto

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