Maximum Hash Partitions 8i

From: Rob Honeyman <r.honeyman_at_inpharmatica.co.uk>
Date: Fri, 4 Jul 2003 13:09:39 +0100
Message-ID: <78eNa.699$95.239@newsr2.u-net.net>

Hi,

I was wondering if anyone has used a very large number of hash partitions on an Oracle 8i database, i.e. 256 or 512 to cope with an extremely large table. The table in question is around 0.5TB with a single bitmap index. Our research shows that we are obtaining partition elimination on the table for all queries, but I am concerned that the overhead caused by the hash calculation may adversely affect performance. At the moment I am using 64 partitions, and the main problem appears to be I/O. I do not have enough memory to cache the whole bitmap index as things stand.

Any information/suggestions greatly appreciated.

Robert Honeyman
Senior Database Administrator
Inpharmatica Ltd.
60 Charlotte St.
London W1T 2NU Received on Fri Jul 04 2003 - 07:09:39 CDT