Re: One sequence or many sequences?

From: Serge Rielau <>
Date: Thu, 26 Jun 2008 10:53:43 -0400
Message-ID: <>

Mark D Powell wrote:
> The practice of using a separate sequence for every table is wasteful
> and unnecessary. It is must more efficient to share a single sequence
> among a collection of low insert rate tables. This practice will
> reduce the number of times Oracle has to flush a sequence from the
> sequence cash to make room for another sequence
Couple of thoughts on this:
* If I have 100 sequences with cache 20 I run out of cache every 20 NEXTVALs somewhere on average. If I have one sequence with cache 20 I run out of cache every 20 NEXTVALs just the same. The difference is in the memory requirement. And of course I can play with the CACHE size. * One sequence means bigger numbers. Bigger numbers mean more space (more digits).
Perhaps that is negligible for a wide row, perhaps not.

I think it boils down to mostly taste...


Serge Rielau
DB2 Solutions Development
IBM Toronto Lab
Received on Thu Jun 26 2008 - 09:53:43 CDT

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