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

Vivek

You spend all days benchmarking...? :-)

I have seen your question regarding benchmarking in the last like 18 months :-P

--
LSC



On 9/24/07, VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com> wrote:


>

>  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 2

> nd 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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