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For example we have upgraded our MySQL 5.5 to 5.7 and we were hit by a performance issue in few GROUP BY queries. Then we decided to use 5.6 instead of 5.7. I t

For example we have upgraded our MySQL 5.5 to 5.7 and we were hit by a performance issue in few GROUP BY queries. Then we decided to use 5.6 instead of 5.7. I think the Oracle corporation doesn't care much about MySQL. Edit: In MySQL 5.5 and 5.6 it takes around 1 second but in 5.7 it takes around 70 seconds.

morgo 10y ago
From MySQL 5.6 to MySQL 5.7, the cost model changes significantly. So while most queries will improve - there are edge cases where regressions occur. In anticipation of this occurring (even if you are better 99% of the time; there will be cases where two wrongs made a right), MySQL 5.7 also added new query hints. I work on the MySQL team; we are 2x the size under Oracle, and have made many improvements. Please check out my list here: http://www.thecompletelistoffeatures.com/ http://www.thecompletelistoffeatures.com/