Re: Performace Degrade after upgrading to 8.1.7.4

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 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 .

Thanks & Regards,
Mahesh Hardikar

> There is no contention for "segment header" so you don't need to add
> any freelists. Since there is contention for "data block", you should
> start by changing PCTFREE and PCTUSED settings. Probably to default
> values of PCTFREE 10 and PCTUSED 40 as mentioned in other post.
>
> Waits for "db file scattered read" and "db file sequential read"
> typically happen during I/O reads. You may want to increase the values
> of db_file_multiblock_read_count and db_block_buffers then check the
> waits on both events.
>
> Regards
> /Rauf Sarwar
Received on Fri Jun 13 2003 - 06:11:47 CEST