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Archives of the TeradataForum
Message Posted: Mon, 25 Apr 2011 @ 11:04:50 GMT
Subj: | | Re: Drop ji and then recreate it to avoid overhead? |
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From: | | Barrineau, Claybourne |
As the other user mentioned, stats appear to be missing in the piece of the explain you posted. Stats are always a good start to addressing
performance issues.
As a rule, we will not support any production processes that alter table header definitions (which you are doing when you drop and recreate
JIs) unless we are 100% certain that nothing can access the respective tables while the alteration is running. Failure to guarantee this can
result in user or batch jobs abending due to a 'Table has been restructured error' or (in some quirky cases) I've seen dead-locking issues that
the database doesn't recognize as a dead-lock.
Granted, if you can guarantee no one will access the respective tables...great, ignore the above. If not, I think you are better off changing
the respective load job to something that supports JIs. If you haven't played around with the 'Fastload to a staging / ANSI merge into a Target'
approach in 12.0, give it a try. In our experience, the performance in most cases (depending on volume) is better than the traditional load
utilities.
Hope this helps,
Clay
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