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MariaDB: Find Users logged into MariaDB

Question:Is there a query to run that will return all Users that are currently logged into MariaDB?

Answer: In MariaDB, there is a system table called information_schema.processlist which shows the threads that are currently running. You can run a query against this system table that returns all of the Users that are currently have a connection running in the MariaDB database.

To retrieve all Users logged into MariaDB, you can execute the following SQL statement:

SELECT SUBSTRING_INDEX(host, ':', 1) AS host_short,
       GROUP_CONCAT(DISTINCT user) AS users,
       COUNT(*) AS threads
FROM information_schema.processlist
GROUP BY host_short
ORDER BY COUNT(*), host_short;

This SELECT statement will return the host, the user, and the number of threads for that host/user combination.

TIP: You must have PROCESS privileges to see threads owned by other users. Otherwise, you will only see your own threads.

The information_schema.processlist table contains the following columns:

Column Explanation
ID Unique identifier
USER User name (ie: root, techonthenet, etc)
HOST Host for the user
DB Database that thread is running in
COMMAND Command that is being run (ie: Query, Sleep, etc).
TIME Number of seconds that thread has been running (ie: 301, 325)
STATE State of thread (ie: executing)
INFO Displays information about the thread. (ie: if COMMAND='Query' and STATE='executing', the SQL that the user is running will be displayed)
TIME_MS Number of milliseconds that thread has been running (ie: 301471.887, 325595.370)
STAGE Stage that the thread is currently in
MAX_STAGE Maximum number of stages
PROGRESS Progress of the current stage (ie: 10%, 95%, etc.)
MEMORY_USED Amount of memory used by the thread (ie: 50200, 82920, etc.)
EXAMINED_ROWS The number of rows examined by the thread
QUERY_ID ID of the query