MySQL Bugs: #76605: slow query with grant all on *.* to xxx

Bug #76605	slow query with grant all on . to xxx
Submitted:	7 Apr 2015 4:32	Modified:	8 Jun 2018 8:16
Reporter:	liu ping	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	MySQL Server: DML	Severity:	S2 (Serious)
Version:	5.6.23 & 5.6.24	OS:	Linux (Linux iZ28ihpu0pyZ 3.10.0-123.9.3.el7.x86_64 #1 SMP Thu Nov 6 15:06:03 UTC 2014 x86_64 x86_64 x86_64)
Assigned to:		CPU Architecture:	Any

Description:
if use grant all on *.*  in MySQL 5.6.23 and MySQL 5.6.24 has very slow query, but use grant all on database.* is fast.

How to repeat:
And we do the following test:
1: delete user test grant in mysql by : delete from user where user='test'
2: use grant all on database1.* to 'test'@'ip_address' IDENTIFIED BY 'test';
3: restart mysql
4: execute the long query 5 times.
in this case , we found the first time is slow, take about 13 second. it's ok, but the second and next times ,the query is very fast, less than 1 second (we use query case).

the other test case:
1: delete user test grant in mysql by : delete from user where user='test'
2: use grant all on *.* to 'test'@'ip_address' IDENTIFIED BY 'test';
3: restart mysql
4: execute the long query 5 times.
and now, the first time also take about 13 second, but the second and next times ,the query also very slow , it's take about 9 second.

why?

in those case, we use the same machine ,same my.cnf file, same MySQL Server instance, same database

Sorry to be late, please try 5.6.40. Thanks.

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".