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Author: Kevin Feasel

Generating Scripts from SSMS

Published 2019-06-03 by Kevin Feasel

Jeff Mlakar shows how you can use Management Studio to generate scripts for database objects:

Sales.SalesOrderDetail looks like a good choice. Let’s generate a script for that table, all associated objects, and its data.

The safest way to create structure including all indexes, keys, defaults, constraints, dependencies, triggers, etc. is to use SSMS Generate Scripts.

I would also recommend becoming familiar with the Powershell command to generate scripts and what dbatools has on store.

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Stats IO Oddities

Published 2019-06-03 by Kevin Feasel

Josh Darnell collects a few cases where SET STATISTICS IO ON doesn’t behave quite as you might expect:

The first one comes from a post on Database Administrators Stack Exchange: STATISTICS IO for parallel index scan

To summarize the situation, the OP had a query that was scanning a clustered index. They were seeing significantly higher numbers reported in the logical reads portion of the STATISTICS IO output when the query ran in parallel vs. serially (with a MAXDOP 1 query hint). There is a demo of this behavior in the post, so I won’t reproduce it here.

There are several interesting cases in here, so check them out.

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Testing dbcreator Privileges

Published 2019-06-03 by Kevin Feasel

Shane O’Neill wants to know whether the dbcreator built-in role has the ability to back up the databases it creates:

I knew from reading the documentation that dbcreator grants permissions to create, alter, drop, and restore databases. My question was does it give permission to backup databases?

It seems to give everything else so is backup databases just missing there? Or is it intentionally left out?

To find out whether it does, click on through.

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Query Store Changes in CTP 3.0

Published 2019-06-03 by Kevin Feasel

Milos Radivojevic notes some changes in Query Store with SQL Server 2019 CTP 3.0:

In addition to default value, the minimum number of query executions in the AUTOquery_capture_mode for storing the query, its plan(s) and runtime statistics in SQL Server 2019 has been increased from 3 to 30. That means, Query Store does not store anything for first 29 query executions. It reserves query_ids, but it starts storing execution plan and runtime stats from 30thexecution in a single day.

These look like reasonable changes to me.

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Unique Key Constraints in Cosmos DB

Published 2019-05-31 by Kevin Feasel

Hasan Savran shows how you can set unique key constraints on Cosmos DB containers:

Unique key names are case-sensitive, I have good experience on this. If your unique key is in lowercase letters but your data has field with uppercase, CosmosDB will insert null value into unique key first time, you will get an error second time when it tries to insert null again. CosmosDB does not support sparse unique keys. If your unique key is /SSN, you can have only one null value in this field.

    If you like to use unique keys in Azure CosmosDB, you have to them when you create your containers. You cannot add a unique key to an existing container. Only way to add a unique key to an existing container is, to create a new container and move your data from older container to the new one. Also, you cannot update unique keys just like partition keys. Picking a wrong unique key can be an expensive error.

Looks like you’ll need to have a bit of foresight when choosing keys (or choosing not to use keys).

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Comparing Sparklines

Published 2019-05-31 by Kevin Feasel

Lisa Charlotte Rost takes us through sparklines:

Sparklines are curious things. They’re supposed to show a trend, and a trend only. They’re supposed to show when something (like stocks) increase and decrease, where the peaks and the valleys are. But sparklines are not supposed to be comparable with each other.

So when you’re seeing two sparklines with the same height, the ebbs and flows of the first one could play out between 0 and 10 (e.g. US-Dollar), while the other sparkline’s peak is at 10,000.

But that’s odd, no? Doesn’t that invite people to make totally false assumptions?

I like sparklines a lot, but I’m apt to violate this particular rule and make them cross-comparable unless I know people will never care about comparisons between elements. One way to get around the “what if the range is big?” problem is to plot sparkline heights as logs so that 1000 is a bit bigger than 100, which is a bit bigger than 10. The argument I make for doing that is you still see size differences and sparkline comparisons are imprecise to begin with, so magnitudes are more important than exact values.

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Defining and Setting Deadlock Priority

Published 2019-05-31 by Kevin Feasel

Dave Bland explains how you can use DEADLOCK_PRIORITY to control which process gets rolled back:

Before getting into how to set the DEADLOCK_PRIORITY, let’s quickly go over what the options are.  There are two ways to set the priority of a process. The first option is to use one of the keywords, LOW, NORMAL or HIGH. The second approach is to use a numeric value between -10 and 10.  The lowest value will be chosen as the victim.  For example, LOW will be the victim of the other process is HIGH and -1 will be the victim if the other process is greater than -1.

As I recall, index operations (like rebuilds) are automatically set to a low priority.

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Getting Version Info From dbatools

Published 2019-05-31 by Kevin Feasel

Jess Pomfret shows how you can get your operating system and SQL Server versions from the dbatools Powershell module:

With these dates on the horizon it’s a good time to look at our estate and make sure we have a good understanding of the versions we currently support. I’m going to show you how to do that easily with a couple of dbatools functions. Then, bonus content, I’ll show you how to present it for your managers with one of my other favourite PowerShell modules ImportExcel.

Jess gets bonus points for avoiding the dreaded pie chart at the end.

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Data Classifications on Azure SQL DW

Published 2019-05-31 by Kevin Feasel

Meagan Longoria takes us through data classifications on Azure SQL Data Warehouse:

Data classifications in Azure SQL DW entered public preview in March 2019. They allow you to label columns in your data warehouse with their information type and sensitivity level. There are built-in classifications, but you can also add custom classifications. This could be an important feature for auditing your storage and use of sensitive data as well as compliance with data regulations such as GDPR. You can export a report of all labeled columns, and you can see who is querying sensitive columns in your audit logs. The Azure Portal will even recommend classifications based upon your column names and data types. You can add the recommended classifications with a simple click of a button.

But read the whole thing, as Meagan sees a problem with it when you use a popular loading technique.

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BimlExpress 2019

Published 2019-05-31 by Kevin Feasel

Cathrine Wilhelmsen digs into BimlExpress 2019:

This is the first major BimlExpress release this year, called the R1 release. There are no new features in this release, but BimlExpress now supports both Visual Studio 2019 and SSIS 2019!

While there are no new features in this release of BimlExpress, there are two changes to Visual Studio that you should be aware of as a Biml developer.

Read on to see what those two changes are.

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