Database Software

Hello All,

I have a question about Oracle RAC and how it balance loading.
What I know about Oracle RAC that it balancing load between its node, so if a new session is connected to the Database it will execute on the node which have less load.
If I am having an application that connects to the database with few number of sessions and some sessions have huge (huge load) processes to execute while the other sessions are executing small process (in terms of load).

So below is an example scenario that i am asking for an answer of it:
if am having a two node RAC database.

My application that is connected to this RAC database wants to execute three processes P1, P2 and P3 each will have a session correspondingly S1, S2 and S3
Let is say that P1 will take 20% of the database resources (memory ....) and P2 will take 1% and P3 1%.
So my question is it a sessions load balancing or Processes load balancing ? So in case and randomly (Managed by ORACLE RAC) S1 is connected to node 1 and it is using node 1 resources so the load on node 1 will be 20%, so when S2 and S3 needs to connect it will go to node 2 since node 1 is loaded. in that case i will have Node 1 using 20% of it is resources (becuase of S1 that is executing P1) while node 2 only uses 2 % (because of S2 and S3 that is executing P2 and P3).
Is that how Oracle RAC works ? or it balance the load of S1 (20%) between node 1 and node 2 ?

I am asking this question since my application is not users application, so it will connect to the database with few number of sessions, and 1 session of them may execute a huge process while the other are executing small processes.
So in that case, how RAC is doing the balance loading?

Iam using SCAN configuration in 11gR2 on AIX machine(2 node cluster), having only one application, and we are using JDBC thin client, We have only the way of load balancing is server side load balancing with SCAN, It is automatic load balancer.

I want the way in which the application has to work with the database should be balancing across the two nodes, not the session balance as mentioned above.

We have 18 tables, If 450 users connected to the database , their entries will update in all the 18 tables, means 450*18 almost 8000 TPS, We are not using SSD , as it is very cost factor, here we are using ASM with 3.5TB, 35 disks each one is 100G,

Now iam reaching 160 users i.e 160 TPS and 160*18 i.e 2880 TPS,

Kindly suggest me , How to reach the 8000 TPS.

Note: Inserts followed by commits, means frequency of commits are very high, During our test period we received the following wait events "log file sync" and "log file parallel write"

How to fix the " virtual circuit waits" netwok evnt , It is consuming 35% of DB Time.

Regards,

Edited by: 911854 on Feb 2, 2012 5:45 AM