MySQL Queue Cache Test

This test monitors the health of the query cache in the MySQL server.

Target of the test : A MySQL server

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the database being monitored

Configurable parameters for the test
  1. TEST PERIOD – How often should the test be executed
  2. Host – The IP address of the MySQL server
  3. Port – The port on which the server is listening
  4. db – the name of a database on the server
  5. Usernameand password - The eG agent has to be configured with the credentials of a user who has server-wide process and select privileges on the monitored MySQL server. To know how to create such a user, refer to Pre-requisites for Monitoring the MySQL Server topic.
  6. Confirm password – Confirm the password by retyping it here.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Queries registered in cache:

Indicates the number of queries that are registered with the cache.

Number

 

Queries added to cache:

Indicates the number of queries added to the cache during the last measurement period.

Number

 

Cache hits:

Indicates the number of times the cache was accessed during the last measurement period.

Number

 

Queries deleted from cache:

Indicates the number of queries that were deleted from the cache during the last measurement period.

Number

A high value could indicate low memory allocation for the query cache. Since reading from the cache is less expensive than reading directly from the database, a higher memory allocation to the cache is advisable.

Non-cached queries:

Indicates the number of queries that were not cached (not cacheable due to their QUERY_CACHE_TYPE) during the last measurement period.

Number

 

Free memory in cache:

Indicates the amount of free memory in the query cache.

MB

A low value of this measure could cause subsequent queries to be rejected by the cache, owing to low memory availability. It would be good practice to tune the cache memory to handle more load. 

Free blocks in cache:

Indicates the number of free memory blocks in the query cache currently.

Number

 

Blocks in cache:

Indicates the total number of blocks in the query cache currently.

Number

 

Queries in cache:

This is the sum of cache inserts, cache hits, and non-cached queries during the last measurement period.

Number