Home » RDBMS Server » Performance Tuning » Bitmap indexes "drop/create" or "disable/rebuild"
Bitmap indexes "drop/create" or "disable/rebuild" [message #377499] Tue, 23 December 2008 04:52 Go to next message
Ferrarist
Messages: 29
Registered: March 2006
Location: Netherlands - Den Haag
Junior Member
Hello,

I was wondering if there's any difference in performance in handling a bitmap index in the next 2 cases:

1. Drop the bitmap index, exchange empty partition with partition that includes a lot of extra rows, (re)create the bitmap index (parallel nologging).

2. Disable the bitmap index, exchange empty partition with partition that includes a lot of extra rows, enable the bitmap index and rebuild (parallel nologging).

Which one of the 2 would be faster or isn't there any difference? Why (not)?

Regards,
Rob
Re: Bitmap indexes "drop/create" or "disable/rebuild" [message #377525 is a reply to message #377499] Tue, 23 December 2008 05:44 Go to previous messageGo to next message
rleishman
Messages: 3724
Registered: October 2005
Location: Melbourne, Australia
Senior Member
I might be missing something here, but in each case aren't you rebuilding the ENTIRE index just for the benefit of ONE partition?

If so, there would be no difference.

However it would be MUCH, MUCH, MUCH, MUCH faster to build the bitmap index on the table BEFORE you do the partition exchange. That way the only rows affected are those in the affected partition.

Ross Leishman
Re: Bitmap indexes "drop/create" or "disable/rebuild" [message #377685 is a reply to message #377525] Wed, 24 December 2008 04:38 Go to previous message
Ferrarist
Messages: 29
Registered: March 2006
Location: Netherlands - Den Haag
Junior Member
Thanks!

That's exactly the hint I'm looking for.
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