Query Data Store–SQL Server 2016

SQL Server’s new Query Data Store is a brilliant option for databases if you are a DBA or have to do performance tuning on T-SQL queries. This new feature of SQL Server 2016 is contained within a database with configuration options for storage of history and query plans. The option has many benefits you can take advantage of today, but also this is an option for future upgrades to new SQL Server versions because of the history contained in the database rather than the instance.

 

To enable the Query Data Store, you have to be db_owner of the database or SysAdmin to the instance. Once you right-click the database in SQL Server Management Studio (SSMS), go to the Query Store menu choice on the left and change Operation Mode (Requested) to Read Write. There are other options to handle the time retention of data as well as how often it is collected.

 

This will enable the database to start storing query execution plans as well as statistics like IO, Read/Write and execution times in the database itself. There are new Data Management Objects (DMVs/DMFs) to use to manual retrieve this data.

 

There are also reports available at the database level in SSMS to view information about query statistics. If you drill into the database in SSMS, you will see an option for Query Store.

 

Here, you will see the four default reports that come with this Option.

1. Regressed Queries – shows query history and changes in statistics
2. Overall Resource Consumption – history of resources used in the database
3. Top resource Consuming Queries – Top x of queries using the most resources
4. Tracked Queries – enables you to see multiple query plans for a T-SQL statement and compare the plans or force a plan

The above is just a summary of what you are able to do, but just start using this feature and you will be amazed at what it enables DBAs and others to drill into. This drilling is just the history of queries on one database rather than you having to sort through all plans for an instance.

SQL Server 2016–Live Query Statistics

WOW!!! The next great update to Execution Plans is a way to watch the processing of rows through iterators while the query runs. Never saw that coming. And even a bonus, you can use SQL Server 2016 Management Studio (SSMS) to watch queries run on versions 2014, 2012 and 2008 R2.

SSMS 2016 can be installed by itself without the server installation. Go here for the installation. Once you install SSMS, you can start to view this addition in SSMS.like Figure 1.

 

Figure 1 – Live Query Statistics

After opening a New Query, go to the Query menu choice and select “Include Live Query Statistics.” You will need a long running query in order to see the processing happening at a slow pace.

Figure 2 – Include Live Query Statistics

Once you start a query, a new tab will show the Live Query Statistics like Figure 3. The dotted lne means the iterator has not finished or has not started.

 

Figure 3 – New Tab

The labeling of the iterators have the usually properties as an Execution Plan plus a running time clock of seconds that this iterator is using. In addition, you can see the “Actual Number of Row” of “Esitmated number of Rows” with a calculated Percent Done (Actual/Estimated). Figure 4 shows 144% for some iterators that have not even finished yet.

 

Figure 4 – Percent Greater Than 100

This is useful to see if estimate number of rows is the same or close to actual number of rows. The percentage will rise above 100 if there are more actual than estimated rows. The query in this case probably could use some performance tuning to get the estimate closer to the actual.

WOW!!!