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MySQL Replication Falling Behind (Lag, Delay) (Doc ID 2256128.1)

Last updated on JANUARY 19, 2022

Applies to:

MySQL Server - Version 5.6 and later
Information in this document applies to any platform.


Disclaimer: Starting from v8.0, some terms have been deprecated. Older releases will only use the deprecated terminology, and new releases will only use new terminology. Please see for a complete list of those changes, and in which minor versions it happened.

On a Replication scenario, the replica server is reported as being lagging or falling behind the source, being the usual symptom the existence of  "seconds_behind_source" different from zero when issuing the command:





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In this Document
 Understanding seconds_behind_source
 What is lagging ?
 All Replicas experiencing the issue
 I/O Thread lagging
 SQL Thread Lagging

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