Re: Sequence Duplicate values ??

From: Jason Judge <jason.judge_at_virgin.net>
Date: Thu, 21 Oct 1999 23:37:54 +0100
Message-ID: <7uo3vo$mkn$1@nclient15-gui.server.virgin.net>

It IS possible to get duplicates in some very nasty circumstances. It happened to us a few weeks ago when all our sequences in an application shot backwards to their previous day's values.

It seems a rogue Oracle process was still running after a database was shut down for maintenance (we worked this much out from the log files later) and it was not noticed when the database was restarted. It somehow kept a memory of the sequences and dumped them into the application about six hours later. This caused much havoc as you would expect, a restore from tape and a large number of disgruntled users to re-enter their data for the morning. Some red faces too.

But this is the first and ONLY time I have EVER seen this happen - so don't take it as the obvious solution to your question! For those interested we were using 7.3.4 on HP-UX.

Regards,

Jason Judge
jason.judge_at_iee.org.uk

P.S. Oracle still have no idea of what mechanism allowed this to happen. The database was working fine for a while, then all of a sudden all our sequences jumped back (some by several thousand counts) and threw up errors all over the shop. Received on Thu Oct 21 1999 - 17:37:54 CDT