# Performance difference between 5.6 and 5.7

**URL:** <https://forums.percona.com/t/performance-difference-between-5-6-and-5-7/6840>\
**Category:** Other MySQL® Questions\
**Created:** [February 5, 2019, 3:00pm UTC](https://forums.percona.com/t/performance-difference-between-5-6-and-5-7/6840 "2019-02-05T15:00:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![chiku](https://avatars.discourse-cdn.com/v4/letter/c/3ab097/32.png) [@chiku](https://forums.percona.com/u/chiku)\
**Post date:** [February 5, 2019, 3:00pm UTC](https://forums.percona.com/t/performance-difference-between-5-6-and-5-7/6840/1 "2019-02-05T15:00:18Z")

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Hello everyone,

I have a performance issue about a query.  
I created 2 serveurs (mysql 5.6 and mysql 5.7), then I restored a big database.  
When I do the query, it seems both server are not using same optimizer chain.  
On percona server 5.7 and pxc 5.7, I got same problem than mysql 5.7.  
How can you explain that? And how can I get same optimizer chain like on 5.6 for same performance?  
I join attachements about explain format=json for more details.

Thank you.

[mysql\_explain\_56.json.txt](https://forums.percona.com/uploads/short-url/tm06bYyfWaGLFwzYXsHzd3Ew3Q7.txt) (2.97 KB)

[mysql\_explain\_57.json.txt](https://forums.percona.com/uploads/short-url/y68sCFjQwBTuph7R5FXyrEwHMoJ.txt) (3.12 KB)

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<div class="post-metadata">

**Author:** ![chiku](https://avatars.discourse-cdn.com/v4/letter/c/3ab097/32.png) [@chiku](https://forums.percona.com/u/chiku)\
**Post date:** [February 6, 2019, 6:02pm UTC](https://forums.percona.com/t/performance-difference-between-5-6-and-5-7/6840/2 "2019-02-06T18:02:05Z")

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Problem solved.

There is new option with 5.7 with optimizer\_switch devired\_merge=on.  
With derived\_merge=off, performance is back.