# Handler\_read Increments with Covering Index?

**URL:** <https://forums.percona.com/t/handler-read-increments-with-covering-index/1222>\
**Category:** Other MySQL® Questions\
**Created:** [July 28, 2009, 9:08am UTC](https://forums.percona.com/t/handler-read-increments-with-covering-index/1222 "2009-07-28T09:08:40Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mysqlbot](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@mysqlbot](https://forums.percona.com/u/mysqlbot)\
**Post date:** [July 28, 2009, 9:08am UTC](https://forums.percona.com/t/handler-read-increments-with-covering-index/1222/1 "2009-07-28T09:08:40Z")

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Has anyone noticed that Handler\_read\_key and Handler\_read\_next will get incremented even on a query that never reads any rows (i.e. has a covering index)?

I’ve been trolling source and can’t quite find the method before ha\_myisam::index\_read() is called where a covering index check is performed to prevent row read.

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**Author:** ![xaprb](https://avatars.discourse-cdn.com/v4/letter/x/49beb7/32.png) [@xaprb](https://forums.percona.com/u/xaprb)\
**Post date:** [December 25, 2009, 7:09am UTC](https://forums.percona.com/t/handler-read-increments-with-covering-index/1222/2 "2009-12-25T07:09:21Z")

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How are you finding this? From SHOW STATUS? SHOW STATUS will itself create a temp table and insert into it, then read back from it.