For Devtest version 9.2, for SQL Database Connect I was using keep open connection in the VSM and did not face any connection issues, But when migrated to 10.3 the Model was throwing an error and then going offline until I enabled the "Use connection pool" feature. but again server is not responding even the transaction count is not increasing.
VSE logs shows :
"INFO com.itko.lisa.stats.MetricControllerImpl - Error retrieving metric java.lang.IllegalStateException: Could not put anything new on the event queue"
When using connection pooling for load tests (multi-VUs), you may need to configure the lisa.jdbc.pool.maxPoolSize property not to run out of connections (starvation),
added lisa.jdbc.pool.maxPoolSize=25 ( default is 10) in the local.properties file of the VSM server.