Martin Smith <mfmsith_at_erols.com> wrote:
>We're using bitmaps extensively in a warehouse environment, on HPUX
>10.10. What are the bugs? ...
<snip>
I have found at least 2 bugs/problems with bitmap indexes, though I've
been able to workaround for the most part.
- BITMAP indexes will go into a 'DIRECT LOAD' state if you
disable the primary key. I was rebuilding indexes and had
already completed the bitmaps. Then when the script hit the
primary key, all the bitmaps went south. All those had to be
rebuilt AGAIN.
- Some BITMAP indexes will cause HUGE amounts of redo entries
(and therefore archive-logs). We went from 300 Megabytes per
hour in archive-logs to about 1.3 Gigabytes per hour when I
changed 4 normal indexes to bitmaps. They seemed to be good
candidates for bitmaps since they had less than 16,000
distinct keys and the table had more than 21,000,000 rows.
But alas, I had to change them back to normal ones or go
insane trying to backup archive-logs.
The platform that I'm running on is Digital Unix 3.2d and
the database is 7.3.2.3. Any others find the same problems?
- Doug Anderson
Oracle Database Administrator
DAtheDBA_at_mindspring.com
Received on Thu Apr 17 1997 - 00:00:00 CDT