# Replication show unexpected seconds\_behind\_master

**URL:** <https://forums.percona.com/t/replication-show-unexpected-seconds-behind-master/4477>\
**Category:** Other MySQL® Questions\
**Created:** [October 25, 2015, 1:11pm UTC](https://forums.percona.com/t/replication-show-unexpected-seconds-behind-master/4477 "2015-10-25T13:11:34Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![susantomahato88](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/susantomahato88/32/1050_2.png) [@susantomahato88](https://forums.percona.com/u/susantomahato88)\
**Post date:** [October 25, 2015, 1:11pm UTC](https://forums.percona.com/t/replication-show-unexpected-seconds-behind-master/4477/1 "2015-10-25T13:11:34Z")

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On slave status some time it shows seconds\_behind\_master 0 and suddenly 16555 and again 0 ,is it any type of bug or what can any one please elaborate why it happen i am using percona server 5.6.

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**Author:** ![scott.nemes](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/scott.nemes/32/5_2.png) [@scott.nemes](https://forums.percona.com/u/scott.nemes)\
**Post date:** [October 25, 2015, 5:04pm UTC](https://forums.percona.com/t/replication-show-unexpected-seconds-behind-master/4477/2 "2015-10-25T17:04:51Z")

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Hi susantomahato88;

The seconds\_behind\_master status variable is just an estimate. You likely have DML (i.e. ALTER TABLE) or a large bulk INSERT/UPDATE/DELETE that just finished running. MySQL will see that, and guess that it will take a certain period of time (16555 seconds in your case), but it ends up going much quicker in a lot of cases.

-Scott