Category: Deployment

Ed Elliott has a great post deconstructing the SQL Server Data Tools deployment process:

The first thing to note is the garbage collection, there are like 8 changes to the line so 8 sets of garbage collection that happen which is expensive for a .net app. We get much more processor usage for a more prolonged time and we really start to see some disk activity, write activity just has one peak while the files are written but reading stays quite high throughout the whole process. It could be that it is sql reading from disk (my demo was from a single ssd with a local sql instance) but we can see after the sql cpu settles down the green disk read line stays high so it is unlikely to be pure sqlserver.exe.

What does this tell us?

Well if you have large objects, multi-thousand line stored procs then you better get yourself some serious ssd’s to deploy from. If you have smaller objects then you’ll need CPU and memory – don’t scrimp here!

Check it out.

Richie Lee discusses an alternative to pre-model scripts:

According to the blurb, deployment contributors can perform custom actions when deploying a SQL script. And one such use of deployment contributors would be to alter index builds to be an online operation. Microsoft also have a Github DACExtensions repo, and this is very useful because, and in the interests of full disclosure, I have never written a deployment contributor myself. This is partly because the repo has some very good examples, including the online index issue (this post nicely covers how to make use of deployment contributors.) I know those that have and have explained how they work very well. But I think there are a few challenges w/r/t deployment contributors:

• No one has ever heard of them

• You have to use C#

• They’re not entirely straightforward.

This is a good discussion of deployment contributors, including why we don’t see them more frequently.

Ed Elliott discusses database deployments in uncontrolled environments:

There have been a few discussions on stack overflow recently about how to manage deployments in uncontrolled environments, specifically data migrations. The questions were from an SSDT perspective, I don’t think that SSDT is a great choice for these uncontrolled environments and there are some additional requirements for these uncontrolled environments that need some additional thought and care when creating release scripts (whether manually or using a tool).

Ed has some interesting thoughts here, and I agree with the idea that SQL Server Data Tools deployment scripts are not the best choice when you have people changing schema all around you in unexpected ways.

Richie Lee has concerns with database deployments:

At any rate, the script is generated and maybe reviewed….. so then what? In SSDT there is no way to create and deploy script in one step; they are two distinct steps. And even if they were one step, this would still not resolve the issue that troubles me. So what is this issue?

The issue is that by creating a script, and then running the deploy, you cannot be sure that the database is in the exact same state that it was when the initial script was generated. If you don’t already know, SSDT runs a deploy entirely in memory, so as mentioned there is no script created. You have to explicitly create the script as part of the process. Or, if you have already created one, you have to re-create the script.

I’m on the fence here.  In simpler environments, I think Richie has a good point.  But in a complex environment, I wouldn’t even use auto-generated deployment scripts; when you’re changing hundreds of database objects (including adding and modifying columns, backfilling data, modifying indexes, etc.), that automated deployment script is almost guaranteed to fail.  And if it does fail, it could leave you in a state of irreparable harm.