Azure SQL Root Blockers Test

One common problem encountered with databases is blocking. Suppose that process A is modifying data that process B wants to use. Process B will be blocked until process A has completed what it is doing. This is only one type of blocking situation; others exist and are common. What matters to a database administrator is identifying when blocking is a problem and how to deal with it effectively. When blocking is bad enough, users will notice slowdowns and complain about it. With a large number of users, it is common for tens or hundreds of processes to be blocked when slowdowns are noticed. Killing these processes may or may not solve the problem because 10 processes may be blocked by process B, while process B itself is blocked by process A. Issuing 10 kill statements for the processes blocked by B probably will not help, as new processes will simply become blocked by B. Killing process B may or may not help, because then the next process that was blocked by B, which is given execution time, may get blocked by process A and become the process that is blocking the other 9 remaining processes. When you have lots of blocking that is not resolving in a reasonable amount of time you need to identify the root blocker, or the process at the top of the tree of blocked processes. Imagine again that you have 10 processes blocked by process B, and process B is blocked by process A. If A is not blocked by anything, but is itself responsible for lots of blocking (B and the 10 processes waiting on B), then A would be the root blocker. (Think of it as a traffic jam.) Killing A (via kill) is likely to unblock B, and once B completes, the 10 processes waiting on B are also likely to complete successfully.

This test monitors the number of root blocker processes in the target Microsoft Azure SQL database. In addition, this test also helps administrators to the number of processes that are blocked by the root blockers and the maximum time for which the processes were blocked.

Target of the test : A Microsoft Azure SQL database

Agent deploying the test : A remote agent

Outputs of the test : One set of results for the Azure SQL database that is configured for monitoring

Configurable parameters for the test

Parameters	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 Name	Specify the name of the Azure SQL database that is to be monitored.
User Name and Password	Against the User Name and Password parameters, specify the credentials of the user who is vested with DBOWNER rights to the configured Database Name.
Confirm Password	Confirm the specified Password by retyping it here.
SSL	If the Azure SQL database service being monitored is SSL-enabled, then set the SSL flag to Yes. If not, then set the SSL flag to No.
Domain	By default, none is displayed in this text box. If the ‘SQL server and Windows’ authentication has been enabled for the Azure SQL database being monitored, then the Domain parameter 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 monitored database exists. Also, in such a case, the User Name and Password that you provide should be that of a 'domain user' with DBOWNER rights to the configured Database Name.
IS NTLMv2	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, this flag is set to No, indicating that NTLMv2 is not enabled by default for the target Microsoft Azure SQL database. Set this flag to Yes if NTLMv2 is enabled for the target database.
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
Root blockers	Indicates the number of root blocker processes.	Number	Usually, the number of root blocker processes should be low. If this value increases suddenly, this is a cause for concern. Likewise, if a root-blocker process has been blocking other processes for a long time, it is a reason for further investigation. The detailed diagnosis for this test, if enabled, provides details of the root blocker processes - their SPIDs, programs running these processes, and the queries being issued by these processes. It is usually the case that killing any root-blocker process that has been running for a long while will get the database running well again.
Blocked processes	Indicates the number of processes that are blocked by the root blockers.	Number	Use the detailed diagnosis of this measure to know which processes are blocked.
Maximum waiting time	Indicates the waiting time - i.e., blocked time - of that process(es) that was blocked for the maximum duration.	Secs	If the value of this measure matches or exceeds the MAX BLOCKING TIME configuration of this test, it indicates that one/more processes have been blocked for a very long time. You can then use the detailed diagnosis of this measure to identify these blocked processes and figure out who initiated such processes and their resource usage. Processes that are resource hogs can thus be identified.