Primo MT APAC01 - RCA - July 18, 19, 2018
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 July 18 and 19, 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:
July 18th, 2018 from 7:06 AM until 8:54 AM Singapore time
July 19th, 2018 from 10:04 AM until 10:20 AM Singapore time
During the event, the service was unavailable for the environment.
Root Cause Analysis
Ex Libris Engineers investigated this event to determine the root cause analysis with the following results:
In the event of July 18th the reactive database rules initiated a new execution plan to use a full table scan which affected the search functionality in a way that made the system unavailable.
To solve this the DB was restarted to restore the previous plan and extra monitoring for this specific scenario was added.
In the event of July 19th the extra monitoring revealed a possible optimization that can be applied to the application code
Technical Action Items and Preventive Measures
Ex Libris has taken the following action and preventive measures to avoid such an occurrence in future:
- Restart DB and application to have the system back to full functionality
- Extra monitoring on that specific scenario was added and revealed an application flow that should be optimized.
- A fix for this optimization will be injected in the coming week.
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: http://status.exlibrisgroup.com/