MySQL Bugs: #98824: administrator command: Change user

Bug #98824	administrator command: Change user
Submitted:	4 Mar 2020 7:48	Modified:	5 Mar 2020 4:24
Reporter:	chuck perry	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	5.7.21-log	OS:	CentOS
Assigned to:		CPU Architecture:	Any
Tags:	administrator command, change user

Description:
there's some strange slow logs recorded these days, 

# Time: 2020-03-04T00:40:08.316438+08:00
# User@Host: aaaa[aaaa] @  [xx.xx.xx.xx]  Id: 1177705
# Query_time: 2.298619  Lock_time: 0.000000 Rows_sent: 0  Rows_examined: 0
use bbbbbbbb;
SET timestamp=1583253608;
# administrator command: Change user;
# Time: 2020-03-04T00:40:08.316449+08:00
# User@Host: aaaa[aaaa] @  [xx.xx.xx.xx]  Id: 1177708
# Query_time: 2.298324  Lock_time: 0.000000 Rows_sent: 0  Rows_examined: 0
SET timestamp=1583253608;
# administrator command: Change user;
# Time: 2020-03-04T00:40:08.316463+08:00
# User@Host: aaaa[aaaa] @  [xx.xx.xx.xx]  Id: 1177709
# Query_time: 2.298325  Lock_time: 0.000000 Rows_sent: 0  Rows_examined: 0
SET timestamp=1583253608;
# administrator command: Change user;

so I turn on general log,found these message below

2020-03-04T15:45:55.643100+08:00        1182693 Change user     aaaa@xx.xx.xx.xx on bbbbbbbb using TCP/IP
2020-03-04T15:45:55.644063+08:00        1182577 Change user     aaaa@xx.xx.xx.xx on bbbbbbbb using TCP/IP
2020-03-04T15:45:55.644074+08:00        1182719 Change user     aaaa@xx.xx.xx.xx on bbbbbbbb using TCP/IP
2020-03-04T15:45:55.644271+08:00        1182578 Change user     aaaa@xx.xx.xx.xx on bbbbbbbb using TCP/IP
2020-03-04T15:45:55.644281+08:00        1182579 Change user     aaaa@xx.xx.xx.xx on bbbbbbbb using TCP/IP
2020-03-04T15:45:55.644282+08:00        1182576 Change user     aaaa@xx.xx.xx.xx on bbbbbbbb using TCP/IP
2020-03-04T15:45:55.644282+08:00        1182575 Change user     aaaa@xx.xx.xx.xx on bbbbbbbb using TCP/IP

How to repeat:
I don't kown how it appear and how this happen,so I need your help,thx a lot.

Hi Mr. perry,

Thank you for your bug report.

However, this is not a bug.

Let me explain to you why. After connection, there is (internally on server) a temporary user. Then, user name and password arrive and you have CHANGE_USER command.

So, the slowness comes from typing a password or from slow network, slow hardware or high load.

Not a bug.

first,Thanks for your reply
I'll trace these case as what your suggest.
thanks again.

You are truly welcome !!!