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

Technote (troubleshooting)


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.


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.


Resolving the problem

The semaphore release defect is addressed in RHEL bugzilla 1165277.

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

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

Related information

Configuring client-to-server connections

Document information

More support for: DB2 for Linux, UNIX and Windows
Operating System / Hardware - Other OS/Hardware

Software version: 9.5, 9.7, 10.1, 10.5

Operating system(s): Linux

Reference #: 1691823

Modified date: 24 December 2015

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