There have been incidents where customers experience latency, and it has been identified that there are many requests taking a long time to process that are specific to queries to the Live Feed table (live_message table).

Steps to Reproduce

  1. Customer or alert identifies instance performance degradation or inaccessibility.
  2. Support identifies that the instance is very slow for users because the semaphores are all used up by requests to xmlhttp.do.
  3. The xmlhttp.do is causing requests to back up because they are running hundreds of queries, such as the following:

SELECT live_message0.`sys_id` FROM live_message live_message0 WHERE ((live_message0.`reply_to` IS NULL AND live_message0.`group` = '7cf072f40fb721009799e64be1050ef2') OR live_message0.`sys_id` IN (SELECT live_message0.`reply_to` FROM live_message live_message0 WHERE live_message0.`group` = '7cf072f40fb721009799e64be1050ef2')) AND live_message0.`last_activity` > '2014-10-21 09:22:36' limit 0,1

These queries take several seconds to finish and have no supporting indexes. Adding indexes on live_message (sys_created_on) and on live_message (last_activity) resolves the issue.


To resolve the issue, add indexes on live_message (sys_created_on) and on live_message (last_activity).

Related Problem: PRB610812

Seen In

Berlin Patch 8
Dublin Patch 1
Eureka Patch 1 Hot Fix 2
Eureka Patch 11 Hot Fix 1
Eureka Patch 11 Hot Fix 2
Eureka Patch 13 Hot Fix 2
Eureka Patch 2
Eureka Patch 4

Fixed In


Associated Community Threads

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Article Information

Last Updated:2016-09-08 10:20:45