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    Primo MT EU02 RCA November 16, 2015

    Confidential Information, Disclaimer and Trade Marks


    This document serves as a Root Cause Analysis for the Primo service interruption experienced by Ex Libris customers on November 16, 2015.


    The goal of this document is to share our findings regarding the event, specify the root cause analysis, outline actions to be taken to solve the downtime event, as well as preventive measures Ex Libris is taking to avoid similar cases in future.

    Event Timeline

    Service interruption was experienced by Ex Libris customers served by the Primo Multitenant EU02 instance at the Europe Data Center during the following hours: 

    November 16, 2015 from 3:13 PM until 4:22 PM Central Europe time zone (CET).


    During this interruption, Primo was extremely slow and became not available for
    customers on the European multitenant EU02 environment.

    Root Cause Analysis

    Ex Libris Engineers investigated this event to determine the root cause analysis with the following results:

    The cause for this event was a known software defect in which search scope filtering method
    consume a great amount of CPU and impact the capability of the search engine to handle large
    number of queries.

    Technical Action Items and Preventive Measures

    Ex Libris has taken the following action and preventive measures to avoid such an occurrence in future:

    • During the time the application was unavailable, Ex Libris had added into the environment an emergency code correction that had been in testing for a while – following of the identification of the code defect (about a month ago). Once implemented the emergency code correction had shown an immediate impact on the performance and stability of the environment.
    • The specific emergency code correction is being closely monitored to verify it is handling the identified situations correctly.
    • Ex Libris is working on a significant change to the application safety and blocking mechanism which will allow the application to block abnormal searches from the same session. This change will be implemented on the February release.

    Customer Communication

    ExLibris is committed to providing customers with prompt and ongoing updates during Cloud events. Ongoing and prompt updates on service interruptions appear in the system status portal at this address: