KB-1206 "Communications link failure during rollback(). Transaction resolution unknown" error thrown in application server log

Symptoms

The following error is displayed in application server log:

INFO  [stdout] (ajp-/0.0.0.0:8009-14) 2016-07-06 13:16:52,016 [ajp-/0.0.0.0:8009-14] ERROR org.hibernate.util.JDBCExceptionReporter - Statement cancelled due to timeout or client request
WARN  [com.arjuna.ats.jta] (ajp-/0.0.0.0:8009-14) ARJUNA016045: attempted rollback of < formatId=131077, gtrid_length=29, bqual_length=36, tx_uid=0:ffffac176096:b16e:5776f2fb:4971, node_name=1, branch_uid=0:ffffac176096:b16e:5776f2fb:4975, subordinatenodename=null, eis_name=0 > (org.apache.commons.dbcp2.managed.LocalXAConnectionFactory$LocalXAResource@420114fe) failed with exception code ARJUNA016099: Unknown error code:0: javax.transaction.xa.XAException
...
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Communications link failure during rollback(). Transaction resolution unknown.

Cause

One of the possible causes is the mismatch of the maximum transmission unit (MTU) between the client and server.

Action

To determine the MTU value, run the following command:

ifconfig

This will display the eth0 configurations, along with the MTU value.

To set a new value for the MTU:

ifconfig eth0:0 <IP ADDRESS> netmask 255.255.255.255 mtu <NEW MTU VALUE>

Affected Versions

This article applies to all versions of Appian.