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Day: March 8, 2022

Trivial Plans and Stats Updates

Published 2022-03-08 by Kevin Feasel

Lonny Niederstadt lays out the harshness of reality:

OK.  SQL Server trivial plans for rowstore table INSERT. And related optimizer stats interaction.
TL;DR cached trivial plans for INSERT can be surprisingly stubborn. If a query matches to one, it won’t perform or queue a stats update even if the stats are stale.  If the stats have been updated and would otherwise warrant a per-index plan – but there is a matching cached trivial plan for a per-row plan… outta luck. Might hafta DBCC FREEPROCCACHE or add OPTION(RECOMPILE) hint to make sure a cached trivial plan doesn’t prevent a per-index update for an INSERT when you really want one.

Read on for a dive into the topic.

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The Power of PIVOT and GROUPING SETS

Published 2022-03-08 by Kevin Feasel

Aaron Bertrand builds a report:

Without comprehensive reporting tools (or Excel), it can be cumbersome and frustrating to produce perfect report output from SQL Server SELECT statement or stored procedures. In modern versions, we have access to T-SQL functionality that far exceeds old-school ROLLUP and CUBE, like PIVOT, UNPIVOT, and GROUPING SETS. Let’s look at how to produce output we can easily plug into a simple front end and produce great-looking reports.

GROUPING SETS is one of my favorite under-utilized operators.

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From Access to SQL Server

Published 2022-03-08 by Kevin Feasel

Tom Collins has some tips to make an Access to SQL Server migration more successful:

-Access has a size limit of 2 GB

-Access has a concurrent users limit of 255 users

-Require increased capacity 

The SQL Server Migration Assistant for Access (SSMA) is a very useful tool  offered by Microsoft . 

The main objective of these notes is to supplement the Microsoft documentation and to assist in Access to SQL Server journey.      

Read on for those notes.

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Stringing Azure Data Factory between VNets

Published 2022-03-08 by Kevin Feasel

Ahmed Mahmoud performs networking wizardry:

Customer wants to connect Azure Data Factory on one subscription to an Azure SQL Server on Virtual Machine (SQL VM) on another subscription. check out the architecture diagram below for more clarification.

Click through for that diagram as well as the process. And between VNet peering and Private Link, I believe (but could be wrong in saying) the traffic would never leave Azure-hosted machines even when it transits between subscriptions.

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Query Plans in Azure Data Studio

Published 2022-03-08 by Kevin Feasel

Grant Fritchey is excited:

I have long been a fan of Azure Data Studio, but one shortcoming has kept me from truly adopting it: Query Plans in Azure Data Studio. Sure, there was a plug-in you could install. Also, you could use a somewhat truncated version of Plan Explorer, but all I wanted was for SQL Server Management Studio plans to be query plans in Azure Data Studio.

Go and get version 1.35 of the tool. Right now.

I think there’s still a fair amount of work to do on those plans but it’s a far cry from where they were prior to this.

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Database Offline Works but Online Permissions Failure

Published 2022-03-08 by Kevin Feasel

David Alcock unravels a mystery:

I was browsing the SQL Server subreddit earlier where someone had posted a problem where they’d been able to take a database offline but couldn’t bring the database back online via a script or the UI in SSMS (full thread here).

There’s a bit of a back story; all the DBA’s have left the business (facepalm) so a non-DBA has been left with the admin type tasks. Secondly the reason the database was being taken offline was to take physical backups of the databases mdf and ldf files (double facepalm).

That is its own issue but read on for the problem at hand.

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