MySQL Table Scans Test

Full table scans on a database instance can degrade the performance of the database. This test monitors the extent of full table scans happening on the database.

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 target MySQL database server being monitored

 

Configurable parameters for the test
Parameter Description

Test period

This indicates how often should the test be executed.

Host

Specify the HOST for which this test is to be configured.

Port

Specify the port at which the target host is listening.

Database

Specify the name of a database on the target MySQL 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 server. To know how to create such a user, refer to Pre-requisites for Monitoring the MySQL Server topic.

Confirm Password

Confirm the password by retyping it here.

DD Row Count

By default, the detailed diagnosis of this test, if enabled, will report only the top-10 tables. This is why, the DD Row Count parameter is set to 10 by default. If you want to include more or less tables in detailed diagnosis, then change the value of this parameter accordingly.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Full table scans

Indicates the number of full table scans that happened on the database during the last measurement period.

Number

This type of scan reads all rows from a table and filters out those that do not meet the selection criteria. Full table scans may happen due to several reasons. For instance, the indexes of a table may not be used properly in queries. By tuning the queries, the full table scans can be reduced and the database performance significantly improved.

Maximum rows examined

Indicates the maximum number of rows examined during the last measurement period.

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.