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Message Posted: Mon, 10 Mar 2003 @ 11:43:15 GMT


     
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Subj:   Re: Deadlock
 
From:   Mirjam Berger

Julie,

We experienced the same problem about two years ago when we were working in an environment with "rapid datamarting". We basically had several sessions at the same time that were all creating small datamarts (and their tables) that would only be needed for a brief period. The problem started showing with only very few sessions, and it got even more prominent after we started creating views as well.

The best explanation we could come up with - but it has not been verified by someone at NCR - is that some parts in Teradata can not be made parallel. Every table needs to obtain a system-wide unique ID. This part can only happen sequentielly. And it seems like other objects also needed for the create table might not be locked in the same order. So if you try to create several tables or views at the same time (probably spread over multiple session) you end up with those dead-looks.

We did not find a true fix for this, only a workaround. If a create table statement failed because of deadlock we just re-tried it. This worked well for us, and from your output I take it you already do the same :)

Thanks!

Mirjam



     
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