SQL Unused Indexes Test

One of the balancing acts of SQL Server is the use of indexes.  Too few indexes can cause scans to occur which hurts performance and too many indexes causes overhead for index maintenance during data updates and also a bloated database. Administrators hence need to continuously track which indexes are used and how they are used. Unused indexes in particular can have a negative impact on performance. This is because when the underlying table data is modified, the index may need to be updated also. This takes additional time and can even increase the probability of blocking. To avoid this, administrators need to rapidly isolate the unused indexes and drop them. The Unused Indexes test facilitates this. Using this test, administrators can quickly determine the number of unused indexes in each database, and also understand how badly that index impacts database performance.

This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick Microsoft SQL as the Component type, Performance as the Test type, choose this test from the disabled tests list, and click on the << button to move the test to the ENABLED TESTS list. Finally, click the Update button.

Target of the test : A Microsoft SQL server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every database on the monitored Microsoft SQL server

  1. TEST PERIOD - How often should the test be executed
  2. Host – The host for which the test is to be configured
  3. Port - The port on which the server is listening
  4. ssl – If the Microsoft SQL server being monitored is an SSL-enabled server, then set the ssl flag to Yes. If not, then set the ssl flag to No.
  5. USER – If a Microsoft SQL Server 7.0/2000 is monitored, then provide the name of a SQL user with the Sysadmin role in this text box. While monitoring a Microsoft SQL Server 2005 or above, provide the name of a SQL user with all of the privileges outlined in User Privileges Required for Monitoring Microsoft SQL server.

  6. password - The password of the specified user.
  7. confirm password - Confirm the password by retyping it.
  8. instance – The name of a specific Microsoft SQL instance to be monitored. The default value of this parameter is “default”. To monitor an Microsoft SQL instance named “CFS”, enter this as the value of the “instance” parameter.
  9. domain - By default, none is displayed in the DOMAIN text box. If the ‘SQL server and Windows’ authentication has been enabled for the server being monitored, then the DOMAIN can continue to be none. On the other hand, if ‘Windows only’ authentication has been enabled, then, in the DOMAIN text box, specify the Windows domain in which the managed Microsoft SQL server exists. Also, in such a case, the USER name and PASSWORD that you provide should be that of a user authorized to access the monitored SQL server.
  10. isntlmv2 - In some Windows networks, NTLM (NT LAN Manager) may be enabled. NTLM is a suite of Microsoft security protocols that provides authentication, integrity, and confidentiality to users. NTLM version 2 (“NTLMv2”) was concocted to address the security issues present in NTLM. By default, the isntlmv2 flag is set to No, indicating that NTLMv2 is not enabled by default on the target Microsoft SQL host. Set this flag to Yes if NTLMv2 is enabled on the target host.
  11. ISPASSIVE – If the value chosen is YES, then the Oracle server under consideration is a passive server in an Oracle cluster. No alerts will be generated if the server is not running. Measures will be reported as "Not applicable" by the agent if the server is not up. 
  12. DETAILED DIAGNOSIS - To make diagnosis more efficient and accurate, the eG Enterprise suite 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 enabled/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

Number of Unused Indexes:

Indicates the total number of unused indexes currently found in this database

Number

Use the detailed diagnosis of this measure to know which indexes in a database are unused. The detailed diagnosis also reveals how often each such index has been updated, so that you can assess the unnecessary overheads that the database may have incurred in the process.