Re: Performace Degrade after upgrading to 8.1.7.4

hardikarm_at_yahoo.com (Mahesh Hardikar) wrote in message news:<4a1c57c2.0306122011.334eb391_at_posting.google.com>...
> Hello ,
>
> Thanks for clarification.
> We have db_file_multiblock_read_count = 8
> db_block_buffer_cache is already at a high value of 1.2 GB (4k Block
> size) making total SGA to 1.7 GB (Shared Pool 300 MB). So I don't
> think it will be worth to increase it futher.
> I always see higher Consistent Reads & effectively lower cache hit
> ratio of 45-50 but uers are not complaining abt read performance.
> Should I try lowering db_block_buffers ?

I would suggest changing the block size to atleast 8K but that would mean recreating instance (exp/imp) with new block size.

> I will try setting db_file_multiblock_read_count to a higher value.
>
> Should I change PCTUSED on the fly ? Reimport will not be feasible
> since it takes almost 3-4 hours of downtime .

You can change PCTFREE and PCTUSED dynamically. SQL> alter table foo PCTFREE 10 PCTUSED 40;

Regards
/Rauf Sarwar Received on Sat Jun 14 2003 - 09:21:32 CEST