RE: "latch: cache buffers chains" wait in NON-RAC Benchmark Runs

Thanks Chris, folks

In the Benchmark Run for Batch processes, Setting "_write_clones" to "0" in 
init.ora severely affected the performance Adversely & was removed thereafter.

Cause of the "latch: cache buffers chains" is believed to be "INSERT into IDT 
Table" as this SQL appears on TOP in the section of the "ordered by gets" of 
the Statspack Report.

The IDT Table has 64 HASH partitions partitioned on field Account(A/c) Number.
This is a Bank Accounts Interest processing Program & 1 Record gets inserted 
per Account into IDT Table per Run. Since Account Number is unique per account, 
could the INSERTs with different A/c Numbers still be accessing the SAME Block?

Any Other ideas? ... Will share the Statspack Report, if needed.

Cheers

Vivek
________________________________________
From: Christian Antognini [Christian.Antognini@xxxxxxxxxxxx]
Sent: Friday, February 15, 2008 1:42 PM

Vivek

> How is the "latch: cache buffers chains" wait to be addressed?

Has for any problem, you should start by understanding what is causing
it.

First of all you should find out which statements are experiencing it.
Then, you have to determine if the contention is due to inefficient
execution plans or simply because they are accessing the very same set
of blocks (there might be other causes... but this two are the most
frequent).

Since it is a benchmark, I would not exclude that the benchmark itself
is flawed. E.g. executing the very same SQL statement over and over
again...

> Should "_write_clones" be set to "0"

Why do you think so?

HTH
Chris

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