BitMap Index, OLTP, Oracle expert

[pma...@mitsa.ch]

Hello

I always thought that bitmap indexes in an OLTP environment was not
a good idea (time taken to update the indexes etc..).

(I was even 'taught' this during an Oracle optimisation course)

However having ran Oracle Expert on our database it suggests
creating bitmap indexes on certain tables/columns.

What is your opinion on using BitMap indexes in an OLTP environment ?

Many thanks

Paul

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Before you buy.

[deco...@worldnet.att.net]

If multiple users are performing inserts, updates, and deletes, then
avoid at all costs. If the table is read only, or very infrequently
inserted/updated/deleted then you can use.

The reason is ORACLE cannot take a "bit" lock when updating the index.
Instead, it has to lock the entire block (i.e. thousands of rows).
This will kill your concurrency on write operations.l

ORACLE Expert probably just saw columns frequently used in where
clauses with a low cardinality and recommended bitmap indexes.;

thanks,

dave

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