Connections
This page is part of MariaDB's Documentation.
The parent of this page is: Status Variables for MariaDB Enterprise Server
Topics on this page:
Overview
Shows the number of connection attempts, both successful and unsuccessful.
DETAILS
The Connections
status variable shows the number of connection attempts, both successful and unsuccessful.
Compute Thread Cache Miss Rate
The thread cache miss rate can be computed using the Threads_created
and Connections
status variables:
The
Threads_created
status variable shows how many threads have been created since the server was brought onlineThe
Connections
status variable shows how many new connection attempts have been made since the server was brought online
If you divide Threads_created
by Connections
, that shows the thread cache miss rate:
SELECT threads_created, connections,
(threads_created / connections) AS thread_cache_miss_rate
FROM
(SELECT gs1.VARIABLE_VALUE AS threads_created
FROM information_schema.GLOBAL_STATUS gs1
WHERE gs1.VARIABLE_NAME LIKE 'Threads_created') tc
JOIN
(SELECT gs2.VARIABLE_VALUE AS connections
FROM information_schema.GLOBAL_STATUS gs2
WHERE gs2.VARIABLE_NAME LIKE 'Connections') c;
If the above query is executed at different times, the results can be interpreted in the following way:
If
thread_cache_miss_rate
stays constant or grows and approaches1
, the current thread cache size is not large enough to keep up with new connection requests.If
thread_cache_miss_rate
shrinks and approaches0
, the current thread cache size is either equal to or larger than needed to keep up with new connection requests. To determine whether it is larger than needed, theThreads_cached
status variable can also be monitored to determine whether the thread cache consistently contains too many cached threads.
For information about how to configure the thread cache, see "thread_
EXAMPLES
Show Value with SHOW STATUS
SHOW GLOBAL STATUS
statement can show the global value:
SHOW GLOBAL STATUS
LIKE 'Connections';
Since this status variable is only global scope, SHOW STATUS
and SHOW SESSION STATUS
also show the global value.
Information Schema
The information_schema.GLOBAL_STATUS
table can be queried to obtain the global value:
SELECT *
FROM information_schema.GLOBAL_STATUS
WHERE VARIABLE_NAME LIKE 'Connections';
This status variable is only global scope, so the information_schema.SESSION_STATUS
table can also be queried to obtain the global value:
SELECT *
FROM information_schema.SESSION_STATUS
WHERE VARIABLE_NAME LIKE 'Connections';