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    Primo MT APAC01 - RCA - April 9, 16, 2018

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    Confidential Information, Disclaimer and Trade Marks

    Introduction

    This document serves as a Root Cause Analysis for the Primo service interruption experienced by Ex Libris customers on April 9th and April 16th, 2018.

     

    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 MT APAC01 instance at the APAC Data Center during the following hours: 

    April 9th, 2018 from 12:00 PM until 13:00 PM Singapore time

    April 16th, 2018 from 13:06 PM until 14:02 PM Singapore time.

    During the event, the service was available but slow for the environment

    Root Cause Analysis

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

    A high load on the oracle data base lead to a sever service interruption.

    The root cause to the high load on the oracle was a results of a frequent and un-optimized application SQL query and the increased size of the oracle table that lead to a change in the query execution plan.

    After the first event we enabled advanced Oracle monitoring which highlight the problematic query.

    Ex Libris DBA add index to the table that prevent full table scan and reduce the load on the oracle.
      

    Technical Action Items and Preventive Measures

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

    • Perform audit to the oracle databases in order to make sure they are optimized and indexed.

    • The relevant index was added as part of the out of the box primo configuration 

    • Improve the cleaning process mechanism of the relevant Oracle tables

    Customer Communication

    April 25th session

    May 7th session

    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: http://status.exlibrisgroup.com/