Why are Watchdog Warnings Observed in the NDB Cluster Logs and What to Do? (Doc ID 1642483.1)

Last updated on JULY 21, 2017

Applies to:

MySQL Cluster - Version 7.1 and later
Information in this document applies to any platform.

Goal

When looking into the logs, you may see warnings like:

2014-05-07 13:48:48 [ndbd] INFO     -- Watchdog: User time: 9  System time: 90
2014-05-07 13:48:48 [ndbd] WARNING  -- Watchdog: Warning overslept 224 ms, expected 100 ms.

or

2014-05-09 10:00:03 [ndbd] WARNING  -- Ndb kernel thread 0 is stuck in: Job Handling elapsed=100
2014-05-09 10:00:03 [ndbd] INFO     -- Watchdog: User time: 1243  System time: 24704 

or similar.

The following discusses why warnings occur and what to do about them.

There are other types of watchdog warnings and errors such as for global checkpoints (GCP) and local checkpoints (LCP). These are not discussed here.

Solution

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