Optimizer : wrong index choice, leading to strong performances issues

Description

Hi,

I'm recreating in JIRA a Launchpad bug opened 2 years ago (https://bugs.launchpad.net/maria/+bug/639949), which is itself a follow up of a really annoying MySQL optimiser bug opened 4 years ago (http://bugs.mysql.com/bug.php?id=36817)

To summarize, there are several simple cases where MySQL optimiser doesn't select the right index. This entails strong performance issues (especially when filesorting is involved), and force the developers to hack their applications, using USE INDEX (when it's possible...).

Hoping someone finally takes a look at this serious issue...
Actually it could also help some of my customers to switch to mariadb, because they are also a little bit tired to put USE INDEX everywhere in there code

Thanks and regards,
Jocelyn Fournier

Environment

None

Assignee

Sergei Petrunia

Reporter

jocelyn fournier

Time tracking

0m

Fix versions

Affects versions

Priority

Minor
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