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    June 2015 leap second may effect Oracle servers

                          Oracle Database Tips by Donald BurlesonMay 14, 2015

Question:  How does the May 31st leap second effect Oracle database servers? Will the leap second effect production databases?.


Answer:  this year the last minute of June 30th will be one second longer and "June 30, 2015 23:59:60 will be a valid and correct time, because of the added second. .Oracle has published a note on potential leap second issues and how the upcomping June 2015 leap second may effect Oracle servers. Oracle notes that on Linux servers, a leap second "hang" may occur, causing 100% CPU utilization. Oracle points to serveral MOSC notes on the subject:

"Linux distributions which may be affected include Oracle Enterprise Linux, Red Hat Enterprise Linux, Oracle VM and Oracle Unbreakable Enterprise Kernel. Asianux 2 and 3, based on RHEL 4 and 5, may also be affected. One report of correction to high agent CPU using Note 1472421.1 on SLES11 has also been reported.

Not all customers will be affected, but those, who are affected, may observe higher than normal CPU consumption on their Linux environments where JVM's are utilized.  In Oracle Enterprise Manager ( EM ) , this problem can manifest itself as high CPU consumption with the EM Agent process (which runs on a JVM in EM 12c, for instance).  It is possible that the OMS is also affected.

We would advise customers to review the description of this problem in MOS Note 1472651.1 and take action if they observe that their environment is affected."


  • How Leap Second Affects The OS Clock on Linux and Oracle VM (Doc ID 1453523.1)
  • Leap Second Hang - CPU Can Be Seen at 100% (Doc ID 1472421.1)
  • What Impact Will the Upcoming Leap Second Have on Java (Doc ID 1987418.1)
  • Insert leap seconds into a timestamp column fails with ORA-01852 (Doc ID 1553906.1)
  • Leap seconds (extra second in a year) and impact on the Oracle database. (Doc ID 730795.1)


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