Hosting Operations

Show Active MySQL Sessions

MySQL is slow or rejecting clients and you need a quick view of active sessions.

Command

mysql -e "show full processlist;"

What changed

Nothing changes. MySQL prints current sessions and queries.

Danger

safe

When to use it

Use when MySQL feels saturated, slow, or overloaded.

When not to use it

Do not use this as the kill step; inspect carefully before terminating sessions.

Undo or recovery

No undo needed because this command is read-only.

Expected output

Rows showing connection ID, user, host, database, command, time, state, and query text.

demo script

Disposable terminal steps

mysqladmin status
mysql -e "show processlist;"
mysql -e "show full processlist;"

Terminal transcript Demo JSON

simulated output

What it looks like

disposable vessel

::fixture-ready::
$ mysqladmin status
Uptime: 86400  Threads: 7  Questions: 23890  Slow queries: 3  Opens: 112  Open tables: 64  Queries per second avg: 0.276
::exit-code::0
$ mysql -e "show processlist;"
Id	User	Host	db	Command	Time	State	Info
17	app	10.0.0.12	shop	Query	91	Sending data	select * from orders
18	app	10.0.0.13	shop	Sleep	20		NULL
22	report	10.0.0.30	analytics	Query	680	Copying to tmp table	select customer_id
::exit-code::0
$ mysql -e "show full processlist;"
Id	User	Host	db	Command	Time	State	Info
17	app	10.0.0.12	shop	Query	91	Sending data	select * from orders join order_items
18	app	10.0.0.13	shop	Sleep	20		NULL
22	report	10.0.0.30	analytics	Query	680	Copying to tmp table	select customer_id, sum(total) from orders group by customer_id
::exit-code::0

YouTube Short

List MySQL sessions.

Before restarting MySQL, inspect the process list and see who is connected and what they are doing.

experiments

A/B tests to run

Metric: linkedin_save_rate

A: The app was waiting behind busy sessions.

B: Check MySQL processlist before restart.