MySQL Cluster Query Test

This test reports the performance statistics pertaining to the queries executed on each node in the target MySQL Cluster database server.

Target of the test : A MySQL Cluster

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each node in the target MySQL Cluster database server being monitored

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The host for which the test is to be configured.

Port

The port at which the specified host listens.

Database

Specify the name of a database on the target MySQL Cluster database server being monitored

Username and 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 Cluster database server. To know how to create such a user, refer to Pre-requisites for Monitoring the MySQL Cluster Database Server topic.

Confirm Password

Confirm the password by retyping it here.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Query rate

Indicates the rate at which queries are sent to this node.

Queries/Sec

This is an indicator of the workload on each node.

Slow queries

Indicates the number of queries that have taken more than the ‘long_query_time’ for execution on this node, during the last measurement period.

Number

This value should ideally be 0. If it remains consistently high, the administrator should look to identify and optimize the slow queries.

Compare the value of this measure across nodes to determine the node where too many queries are slow.

Handler read first

Indicates the number of times the first entry was read from an index on this node during the last measurement period.

Number

If the value of this measure is high, it suggests that the server is doing a lot of full index scans.

Handler read key

Indicates the number of requests that were received in the last measurement period, to read a row based on a key.

Number

If the value of this measure is high, it indicates that your queries and tables are properly indexed.

Handler read next

Indicates the number of requests received in the last measurement period, to read the next row in the key order.

Number

This will be incremented if you are querying an index column with a range constraint. This will also be incremented if you are doing an index scan.

Handler read prev

Indicates the number of requests received in the last measurement period, to read the previous row in the key order.

Number

This is mainly used to optimize ORDER BY... DESC.

Handler read rnd next

Indicates the number of requests received in the last measurement period, to read a row based on a fixed position.

Number

This will be high if you are executing a lot of queries that require sorting of the result. If the value of this measure is high, then you probably have a lot of queries that require MySQL to scan whole tables or you have joins that do not use keys properly.

Handler read rnd

Indicates the number of requests received in the last measurement period, to read the next row in the datafile.

Number

This will be high if you are performing a lot of table scans. Generally, this suggests that your tables are not properly indexed or that your queries are not written to use the indexes properly.