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Local DB2 connections may hang on operating system semop() operations on RHEL (or CentOS) 6.6 Linux distrubutions

Troubleshooting


Problem

RHEL or CentOS 6.6 (first seen in kernel level 2.6.32-434.el6) contains a semaphore release defect which may cause DB2 connections to hang when the client and server reside on the same host. Remote connections (i.e. through TCPIP) are not susceptible.

Symptom

DB2 connections may hang. If a stack is generated from the application process using gstack, the the stack will show the semop() function at the top.

semop
sqloSSemP
sqlccipcrecv
sqlccrecv
sqljcReceive
sqljrReceive

Resolving The Problem

The semaphore release defect is addressed in RHEL bugzilla 1165277.

Please visit the following link for the Redhat publically available patch:

https://rhn.redhat.com/errata/RHSA-2015-1272.html

As a workaround, TCP/IP loopback can be used in order to connect to a local database instead of connecting over IPC using the local indirect alias. To create a loopback connection, see Configuring client-to-server connections using the command line processor and use the local hostname and port number when cataloging the TCP/IP node

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Document Information

Modified date:
16 June 2018

UID

swg21691823