Bug #88937 mysql client history file grows without bounds, slows down connecting to server
Submitted: 15 Dec 2017 11:27 Modified: 19 Dec 2017 11:47
Reporter: Riccardo Pizzi Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: Logging Severity:S3 (Non-critical)
Version:5.6.38, 5.7.20 OS:Any
Assigned to: CPU Architecture:Any

[15 Dec 2017 11:27] Riccardo Pizzi
Description:
The file .mysql_history created by the mysql client seems to grow without bounds. 
When its size becomes important (> 100MB), connecting to a server with the client becomes slow, and the slowness increases with history file size.

This also happens at logout time, when the client has to update the history - I would expect the client to only append to it and this should be fast, however it is re-reading the entire file for some reason, which seems sub-optimal.

How to repeat:
Create a huge .mysql_history file with the following script:

echo "select 1" > file.txt; for i in {1..24}; do cat file.txt file.txt > file2.txt && mv file2.txt file.txt; done; mv file.txt .mysql_history

Try to connect to localhost:

mysql -u user -p ....

Wait several seconds (depending on speed of your home directory's storage) before getting a prompt

Suggested fix:
Limit the history file to a rotation of, let's say, last 5000 statements or so (maybe make that number configurable)
[19 Dec 2017 11:47] Umesh Shastry
Hello Riccardo Pizzi,

Thank you for the report and feedback.
Observed the delay while connecting/disconnecting when .mysql_history file size was large(>100Mb delay is noticeable). 

Thanks,
Umesh