XA making multiple connections with MQ manager

[ramit21]

We are using XA as a transaction manager in our spring boot application for all our IBM Websphere MQ based flows including DB operations. But our application is making multiple connections (1000+ each day) with the queue manager. This is despite the fact that we are using poolsize of 25 in PoolingConnectionFActory settings. Can someone please advise on the possible reasons?
Is it that connections are not getting closed properly, or is it the 2 phase commit protocol of XA creating multiple pings to connection?

[ramit21]

Can anyone please help above.

[fall14123]

@ramit21 which WMQ (or rebranded as IBM MQ...) version are you using on client and server side? We tried using [v9 client + v6 server] and saw multiple connection attempts within a single XAQueueConnectionFactory#createXAConnection().

IBM KC suggests using "migration mode" (ref. link), but doesn't seem help us out yet....

Also asked in https://stackoverflow.com/questions/52655619/wmq-connection-socket-constantly-closed-between-v9-client-and-v6-server?noredirect=1#comment92601694_52655619, in case it's helpful to someone.

[ramit21]

Hi @fall14123 , we are using version 8 of MQ. Tried playing around with providerVersion as suggested by you, but no luck. In fact giving provierVersion as 6 only made things worse and more connections leaked. One difference between your code (as on stackoverflow link) and ours is that we are using Bitronix PoolingConnectionFactory for JMS and PoolingDataSource for DB connections. Another observation is that connections leak when we either produce or consume messages concurrently (a burst of messages). For some reason, PoolingConnectionFactory is not honouring the poolsize that we have given as 20.

PoolingConnectionFactory connectionFactory = new PoolingConnectionFactory();
connectionFactory.setClassName("com.ibm.mq.jms.MQXAQueueConnectionFactory");
connectionFactory.setUniqueName(XA_FACTORY_NAME);
connectionFactory.setAllowLocalTransactions(false);
connectionFactory.setTestConnections(true);
connectionFactory.setUser(user);
connectionFactory.setPassword(password);
connectionFactory.setMaxPoolSize(20);
Properties driverProperties = connectionFactory.getDriverProperties();
driverProperties.setProperty("port", ...);
driverProperties.setProperty("transportType", ...);
driverProperties.setProperty("channel", ...);
driverProperties.setProperty("hostName", ...);
driverProperties.setProperty("queueManager", ...);

All at sea with this connection leak issue. Rasied it with more details on StackOverflow as well - https://stackoverflow.com/questions/53334069/bitronix-poolingconnectionfactory-making-multiple-connections-that-wont-close