Database connection problem SQL Error: 20, SQLState: 61000

Question

we are doing stress test on our new web site that uses vaadin framework and hibernate. Our application/web server is apache tomcat and maximum thread number is adjusted to 750.
we are using jmeter for stress test and when we send 500 user scenario (approximately 15 - 20 database connection per user) in 30 seconds
we are encountered the following error:
*14:43:10,502 WARN JDBCExceptionReporter:233 - SQL Error: 20, SQLState: 61000*
*14:43:10,503 ERROR JDBCExceptionReporter:234 - The Network Adapter could not establish the connection*
but if we send 500 user in 45 seconds there is no problem, jmeter test is completed with 100% success. even if we send 900 user in 120 or 180 second it is OK.
it seems that there is a DB related parameter that we could not handle properly or maybe operating system limitation (windows 2008 R2).
any help will be appreciated. thanks in advance.
gokhan
Edited by: gokhangulgezen on May 31, 2011 6:38 AM

Answer 1

It's the DBMS. Oracle particularly can react this way when there are too many connection requests
coming in, whether from multiple threads at once, or even from one thread in a tight loop. I do
not know if there's a way to moderate/adjust this. I typically recommend using connection-pooling,
and to do as much as possible to populate the pool before there is application load.
Joe