Monthly Archives: December 2015

AlwaysOn Availability Groups – Query to Find Latency Part 3

Posted by on December 30, 2015 Comments Off on AlwaysOn Availability Groups – Query to Find Latency Part 3

Like Part 1 and Part 2, I use a similar query to find latency in AlwaysOn Availability Groups. The queries will return one line for each DB in the group. Part 1 , we looked at a simple query to grab the current status of the replica. Part 2, we looked at populating a Global Temp table every minute to gain a historical perspective of our AG latency. This query will look into creating an email notification when certain criteria is met. It will send the current status to a specific set of email recipients.

The example will be around specific criteria set as a step used in a SQL Agent job. If you use something like this, you need to tweak it to you organization’s needs. I do suggest that you set the job to a frequency that will not overflow your inbox with notices.

Send an email from server when latency for a specfic database datbase is over x number of minutes.

  •  Alter If statement > value for specific needs. This example fires of fthe email when latency is over 60 minutes.
  •  Alter “database_id = DB_ID(‘MyAGDatabase’)” to specify datbase to monitor
  • Alter “@recipients=N’[email protected];” to specify recipients. I suggest using a email distribution list over listing spefic emails.

The example is pretty simple and intended for demonstration purposes.

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AlwaysOn Availability Groups – Query to Find Latency Part 2

Posted by on December 30, 2015 Comments Off on AlwaysOn Availability Groups – Query to Find Latency Part 2

Sometimes there is a need to maintain some historical content on how current your Availability Group is performing. The following script builds off the original script in Part 1. It populates a global temp table with information every minute. I really got the idea from Brent Ozar’s sp_SQL Blitz. I took the road of least intrusive by creating the ##LatencyCheck_tbl global temp table. Sergey Gigoyan has a good post on global temp tables and good links at the end of the post, too.

The ##LatencyCheck_tbl temp table is populated after 1 minute and every minute until cancelled. Need to make sue the table gets dropped after you have done you analysis. It is a good idea to keep an eye on the size of the table, too (execute sp_spaceused ‘##LatencyCheck_tbl’). Like any temp table, service restart will drop the table the process cancelled. If this is something you would like always run. you can look into creating a SQL Agent job or even a procedure that auto starts. I don’t suggest doing that. If you do choose to do so, you should make sure you monitor of have a process in place to reduce the size of the temp table. Also, look into grabbing Perfmon counters and Extended Events. Everything has overhead and we do not want to succumb to the “Watcher Effect”..DAH! DAH! [Organ music].

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AlwaysOn Availability Groups – Query to Find Latency Part 1

Posted by on December 29, 2015 Comments Off on AlwaysOn Availability Groups – Query to Find Latency Part 1

AlwaysOn Availability Groups latency can be a real concern. Microsoft provides a AlwaysON Dashboard to monitor and some administration of Availability Groups in SQL Server Management Studio(SSMS). Ben Snaidero as an excellent posting about the dashboard and T-SQL monitoring of AG.

The query below uses sys.dm_hadr_database_replica_states to query the current state. It can be run on the primary or secondary server. We use a readable secondary and it is nice to see how close to real-time updates. As a roll-your-own solution, you could create a SQL Agent job to monitor and send an email when certain criteria is met.

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Script to Get SQL Agent Job History

Posted by on December 27, 2015 Comments Off on Script to Get SQL Agent Job History

Wanted to share this script. I pieced it together some time ago from various scripts. I think this might be the source for at least some of the query.

Removing the step_ID from the where clause will show run times by step_id and Total RunTime (step_id 0).
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Simple Index Usage Query

Posted by on December 27, 2015 Comments Off on Simple Index Usage Query

Yes, another index usage query. I adapted this a tiny bit to add a time element to it. DMVs will flush out any information when the services are restarted. I omitted system usage information to gear it more toward user created objects. Also, added the users statistics together to get a better Idea of total usage. It gives the user a good starting point to see utilization of current indexing. Conversely, Microsoft provides a “Missing indexes” DMV named sys.dm_db_missing_index_details. Don’t have blind faith in the suggestions. They are based on specific activity since last restart.
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Query to View Active Sessions

Posted by on December 27, 2015 Comments Off on Query to View Active Sessions

I want to start out by saying I am not sure about the origin of this query. I use it frequently to find activity on my servers. I left some of the code commented to show a few example items you can add and additional search criteria. I really encourage anyone to grab a query and alter it to show information useful to them.

It uses sys.dm_exec_query_plan() (via inline select forgive me) to grab the query plan when possible. Additional information to grab performance information and SQL code executing uses these DMVs sys.dm_exec_requests, sys.sysprocesses and CROSS APPLY sys.dm_exec_sql_text(). Use the links to see the information being returned.

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T-SQL: Cursor Example

Posted by on December 27, 2015 Comments Off on T-SQL: Cursor Example

ARTICLE FROM ORIGINAL SITE – Young and Dumb!

Database Cursors have long been a favorite of mine. It allows you to take a subset of data and output the information in various ways. I use them for such things as building the body of an automated email with a cursor set within a stored proceedure. You can return output to build a cleaner report output, etc.Example

Select 'Case Created: '+convert(Varchar(20), @DATE ) + ' Case Number: '+ convert(varchar(10), @CaseNum)

We will start with the basic frame work and build from that:

We will use a two tables named SomeTable and Other Table
(The tables are actually from MySQL – I was lazy.)
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T-SQL: Select Case Example

Posted by on December 27, 2015 Comments Off on T-SQL: Select Case Example

ARTICLE FROM ORIGINAL SITE – Young and Dumb!

Select Case allows you to present data in various way. You can take numbers and return text values and express
certian conditions based on the value of a certain column.

Another example would be that you have a table Naughty_Nice in the Santa Database a data column Nice (INT Datatype) .
There are two distinct values in the column. The Value of 0 equals ‘No’ and the value 1 equals yes. You wanted to speed
stuff up and use less space by selecting a number and not use text Naughty/Nice.

Santa needs a list and he complains that 1 and 0 will not make sense to him at 30,000 feet. It’s so hard to
communicate to a guy that still thinks wooden toys are a big hit. He’s a bit too hands-on, and lacks the technical
skills to really understand that we want to optimize the database.
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