Session Allocation latch contention - limiting concurrent SQL

  • From: scott.hutchinson@xxxxxxxxxxxxxxxxxxxxx
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Thu, 10 Feb 2005 10:14:33 +0000

I have a problem where I can not increase the number of concurrent SQL 
statements running through our system. I believe this is caused by contention 
on the SESSION ALLOCATION latch while internal stats are being updated. 

The highest number of SQL statements I can run is 30,000 per second. I am 
running SAP code to migration many millions of customers into SAP, so we are 
limited with the number of code changes we can make. I've set timed_statistics 
to false and statistics_level to basic. I see very high values in 
V$LATCH.WAIT_TIME for this latch(**per second**:60000 Gets, 22000 Misses, 17000 
Spin gets, 5000 sleeps, 12 secs Wait time).  

Does anyone have suggestions (other than RAC) for ways to overcome this? The DB 
server has 32 CPUs, and we have 9 application severs running the code (with a 
total of 96 CPUs). 

Scott Hutchinson
Interact Analysis Ltd

::This message sent using the free Web Mail service from

Other related posts: