MySQL - Graphs
SHOW STATUS LIKE 'Connections'

Threads_connected: The number of clients currently connected to the server. If its value is often close to the value of max_connections, it might be good to increase the value of max_connections to allow more connections. If clients that should be able to connect frequently cannot, that too is an indication that max_connections is too small. Each active connection handler / thread requires some memory, so you don't necessarily want to set max_connections to the number of threads allowed by the operating system.

Questions / Uptime: how many queries per second the server has processed.

Slow_queries: indicates the number of queries that take a long time to process. Ideally, its value should increase slowly or not at all. If it increase quickly, you may have problem with certain queries.

Threads_created (status variable): The number of threads created to handle connections. If Threads_created is big, you may want to increase the thread_cache_size value. The cache miss rate can be calculated as Threads_created/Connections.

To determine whether the table cache is large enough, check the Open_tables and Opened_tables status variables over time. Open_tables indicates how many tables currently are open, and Opened_tables indicates how many table-opening operations the server has performed since it started. If Open_tables is usually at or near the value of table_cache, and the value of Opened_tables increase steadily, it indicates that the table cache is being used to its capacity and the the server often has to close tables in the cache so that it can open other tables. This is a sign that the table cache is too small and that you should increase the value of table_cache

The back_log system variable

The MyISAM Key Cache

The InnoDB Buffer Pool and Log Buffers (page 557)

Connections (status variable): The number of connection attempts (successful or not) to the MySQL server.

Connections: total number of connection attempts (both successful, and unsuccessful)

Aborted_connects: The number of unsuccessful connection attempts

Connections - Aborted_connects: The number of successful connection attempts.

Aborted_clients: The number of successful connections that terminate abnormally (if the client die, or network went down)

Connections - Aborted_connects - Aborted_clients: The number of successful connections that terminate normally.

The Com variables give us a break down of the number of statements that the server has executed by statement type. You can see all these variables:

Com_delete

Com_update

Com_select does not include the number of queries that are processed by the query cache.

Questions: The number of queries the server has processed.

Uptime: The number of seconds the server has been running

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