Application starts to report intermittently communication error during the execution of SQL statement. Problem is specific to connections to the z/OS server.
After client upgrade to v10.5fp2 or above an application intermittently reports the communication error.
We changed the default setting for INTERRUPT (CLI /ODBC configuration keyword) and InterruptProcessingMode (IBM data server driver configuration keyword) from 1 to 2 for connections to DB2 for z/OS servers.
With default value of 2: Interrupt drops the connection regardless of server's interrupt capabilities (the SQLCancel function call drops the connection) and this results in error SQL30081n with reason code EINTR (10004 - on Windows; 4 - other operating systems)
Client v10.5fp2 or above <-----> Db2 for z/OS servers
Diagnosing The Problem
Analyze CLI trace and if the error reported after execution of the query was interrupted by SQLCancel() request and the IBM Data Server Client level is v10.5fp2 or above please apply the workaround mentioned below.
Resolving The Problem
Set INTERRUPT (db2cli.ini file) / InterruptProcessingMode (db2dsdriver.cfg file) to 1 - to the default value prior to v10.5fp2.
16 June 2018