Re: Tx lock problem with bitmap index

"Niall Litchfield" <niall.litchfield_at_dial.pipex.com> wrote in message news:3e02388d$0$230$cc9e4d1f_at_news.dial.pipex.com...
> "Paul Brewer" <paul_at_paul.brewers.org.uk> wrote in message
> news:3e00ec97_1_at_mk-nntp-1.news.uk.worldonline.com...
> > In other words, don't use them unless this is a DW being rebuilt
> overnight?
>
> I very nearly posted a similar reply to Jonathans (though probably
> inaccurate) with the comment "bitmap indices are really a datawarehouse
> construct, but can also be useful for static tables of relatively low
> cardinality", but the Outlook express crashed when adding a signature a
too
> common occurrence. My point bitmap indices can be use ful in OLTP
> environments the requirement is a (relatively) static table not one with
> zero DML.
>

I'd go a bit further and say that a table can be thrashed to death, provided the key columns on which the bitmap indices are built are static.

But that's a hard one to abide by... quite often, even when you think you've updated only a non-key column, an app. will actually perform the transaction by updating every damn column of the table (Oracle Forms does this a lot, for example).

So, probably in practice, yup: static *tables*.

Regards
HJR
>
> --
> Niall Litchfield
> Oracle DBA
> Audit Commission UK
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Received on Thu Dec 19 2002 - 15:26:41 CST