CPU Usage % on 2-Node RAC Run versus Single Node RAC Run .... Benchmarking

Folks

Comparative Benchmark is being done for the following 2 Cases:-

CASE 1 - When Executing a FULL Set of Transactions on Node 1, with the 2nd Node's RAC instance in SHUTDOWN Condition CPU Usage of Node 1 = 20 %

CASE 2 - When Executing approx Half the above Number of Transactions on Node 1, & the Other Half on Node 2 (by setting LOAD_BALANCE = yes in tnsnames.ora) CPU Usage of Node 1 = 18 %
CPU Usage of Node 2 = 19 %

OBSERVATION - Though the SAME SQLs (SELECT Queries) are appearing as the TOP CPU Consuming in BOTH Cases, these SQLs seem to be consuming MORE CPU in the 2-Node RAC Run (Case2) versus the Single Node Run (Case 1). Qs 2 - Any Advice Why?
Qs 3 - Can the LOAD_BALANCE = yes setting be the possible Cause for the Almost Double CPU Usage of 2-Node RAC 37 % (18+19) versus Single Node RAC Run (20%).

NOTE - Database Connections are PRE-Spawned before Start of Benchmark Run.

Qs 3 - Will Data Partitioning (Business Transactions occurring on Different Table/Index Blocks in the 2 RAC instances) help reduce CPU Usage in the following Statspack scenario? Since the Values for "gc cr block busy", "gc cr block 2-way" events below are relatively SMALL, will Data partitioning have any significant impact on the CPU Usage of the 2 RAC Nodes?

Will provide FULL Statspack Report to any, as needed.

Cheers & Thanks

Statspack From Node 1 during 2-Node RAC Run

Top 5 Timed Events                                                    Avg %Total
~~~~~~~~~~~~~~~~~~                                                   wait   Call
Event                                            Waits    Time (s)   (ms)   Time


----------------------------------------- ------------ ----------- ------ ------

CPU time                                                       138          47.2
log file sync                                   11,188          42      4   14.4
log file parallel write                         12,463          35      3   12.0
gc cr block busy                                 2,420          16      6    5.4
gcs log flush sync                               6,063           9      2    3.2

          -------------------------------------------------------------

Configuration
Oracle 10gR2 - 2-Node RAC-ASM Setup
Solaris 10
Application = Banking Product
Transactions are OLTP in nature.

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http://www.freelists.org/webpage/oracle-l Received on Mon Sep 24 2007 - 10:36:59 CDT