Public bug reported:
I have been using MySQL 5.7.23 in Ubuntu 18.04 installed from offical
repo. It is working fine fine until we tried to take a dump of the
databases. The mysql server contains around 500 small databases which I
used to take individual DB dumps using for loop and mysqldump command in
bash script. The script works fine with MySQL 5.7 installed in Ubuntu
14.04. However, when we start the dump in Ubuntu 18.04, it starts
swapping aggressively and does not release the memory even after
individual database dump is completed. After sometime, memory and swap
becomes almost full, then also CPU starts increasing due to too much
swapping. This caused the server to freeze due to high cpu or mysql
server to crash due to OOM.
Note: I will keep adding more info as I get it.
How to repeat:
Setup MySQL 5.7 in Ubuntu 18.04 on AWS T2.Small.
Create about 400-500 small databases
Try to take backup of all databases using mysqldump command
** Affects: mysql-5.7 (Ubuntu)
Importance: Undecided
Status: New
** Description changed:
I have been using MySQL 5.7.23 in Ubuntu 18.04 installed from offical
repo. It is working fine fine until we tried to take a dump of the
databases. The mysql server contains around 500 small databases which I
- used to take backup using for loop and mysqldump in bash script. The
- script works fine with MySQL 5.7 installed in Ubuntu 14.04. However,
- when we start the dump in Ubuntu 18.04, it starts swapping aggressively
- and does not release the memory even after individual database dump is
- completely. After sometime, memory and swap becomes almost full, then
- also CPU starts increasing due to too much swapping. This caused the
- server to freeze due to high cpu or mysql server to crash due to OOM.
+ used to take individual DB dumps using for loop and mysqldump command in
+ bash script. The script works fine with MySQL 5.7 installed in Ubuntu
+ 14.04. However, when we start the dump in Ubuntu 18.04, it starts
+ swapping aggressively and does not release the memory even after
+ individual database dump is completed. After sometime, memory and swap
+ becomes almost full, then also CPU starts increasing due to too much
+ swapping. This caused the server to freeze due to high cpu or mysql
+ server to crash due to OOM.
Note: I will keep adding more info as I get it.
How to repeat:
- Setup MySQL 5.7 in Ubuntu 18.04 on AWS T2.Small.
+ Setup MySQL 5.7 in Ubuntu 18.04 on AWS T2.Small.
Create about 400-500 small databases
Try to take backup of all databases using mysqldump command
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https://bugs.launchpad.net/bugs/1789343
Title:
mysqldump in MySQL 5.7 running on Ubuntu 18.04 does not release memory
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