09-06-2016 05:37 AM
For comparision, can you post what it took on other releases that you may have tried? Also, would you be able to post the full query, if its ok to publish it to a public forum.
09-10-2016 03:38 AM
Does the query have JOIN operator over partitioned data? If yes, I suggest you run EXPLAIN EXTENDED on the query to check if you can see the query will scan more than intended partitions.
There is a known issue in 5.7.x that partition pruning is not working correctly under certain JOIN conditions.