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A resource-hungry or a long-running query is one of the main reasons for performance degradation of the target database server instance in a cluster. When such queries execute on the cluster server, they hog almost all the available resources or keep the resources locked for long time periods, thus leaving little to no resources for carrying out other critical database operations. This can significantly slowdown the database server and adversely impact user experience with the cluster server. To ensure peak performance of the target cluster at all times, such queries should be rapidly identified and quickly optimized to minimize resource usage. This is where the MySQLCluWrkLdTest test helps.

At configured intervals, this test reports the maximum number of internal on-disk temporary tables created by the server while executing statements. This test also reports how long did a query take for execution and how long did a query spend waiting for table locks. In addition, this test also throws light on the count of table scans that happened on the database server instance. Using the detailed diagnostics of this test, administrators can figure out inefficient queries and proceed to optimize them to enhance server performance.

Outputs of the test :One set of results for the target cluster being monitored.

Measurement	Description	Measurement Unit	Interpretation
Max_temptable_created	Indicates the maximum number of internal on-disk temporary tables created by the server while executing statements.	Number	In some cases, the server creates internal temporary tables while processing statements. Users have no direct control over when this occurs. If an internal temporary table is created as an in-memory table but becomes too large, MySQL automatically converts it to an on-disk table. The detailed diagnosis of this measure lists the Thread ID, Statement ID, Schema name, Query duration, Table lock wait time(Seconds), Temp disk tables created, Temp tables created, Rows sent, Rows examined, Select scan, Sort scan and SQL text.
MaxTableLckWaitTime	Indicates the maximum time spent by a query while waiting for a table lock.	MB	If the value of this measure is high, there may be an impact on the performance of the database server. To improve the performance, administrators need to optimize the queries, either split one / more tables or use replication. The detailed diagnosis of this measure lists the Thread ID, Statement ID, Schema name, Query duration, Table lock wait time(Seconds), Temp disk tables created, Temp tables created, Rows sent, Rows examined, Select scan, Sort scan and SQL text.
MaxQueryDuration	Indicates the maximum time duration taken by the top query for execution.		The detailed diagnosis of this measure lists the Thread ID, Statement ID, Schema name, Query duration, Table lock wait time(Seconds), Temp disk tables created, Temp tables created, Rows sent, Rows examined, Select scan, Sort scan and SQL text. Using the detailed diagnosis, administrators can determine the top 5 queries based on the execution time.
Table_scans	Indicates the total number of table scans that happened on the database instance in the cluster.	Number	The detailed diagnosis of this measure lists the Thread ID, Statement ID, Schema name, Query duration, Table lock wait time(Seconds), Temp disk tables created, Temp tables created, Rows sent, Rows examined, Select scan, Sort scan and SQL text.