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.