Re: Maximum Hash Partitions 8i

I do not have experience with 500 Gb tables and I do not know if there is an upper limit to the number of partitions a table can be partitioned into. The maximum I used is a table partitioned in 12 partitions where each partition is subpartitioned into 64 subpartitions: this ends up into 12*64 = 768 partitions and the same number of segments.

Did you also partitioned your index? The manual says that BITMAP indexes can (only) be LOCAL partitioned. Never tried this.

"Rob Honeyman" <r.honeyman_at_inpharmatica.co.uk> wrote in message news:78eNa.699$95.239_at_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 Sat Jul 05 2003 - 05:28:47 CDT