Database Mirroring is Back in Azure SQL Database

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Database Mirroring is Back in Azure SQL Database

Steve Jones - SSC Editor

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March 30, 2024 at 12:00 am

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Comments posted to this topic are about the item Database Mirroring is Back in Azure SQL Database

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Jeff Moden SSC Guru Points: 1004378 More actions · Answer 1

Remember the company that we're talking about...

It's the company that couldn't see the benefit of a series generator for more than 15 years and, when they finally did release it, it's a fairly crippled version that also breaks minimal logging.

It's the company that initially released a text splitter that didn't return the ordinal position of the elements and had no way to guarantee the enumeration for such a thing. Then, it took them 6 years to release a fix for that.

It's the company that release a seriously crippled version of PIVOT... and still hasn't fixed that.

It's the company that released the FORMAT function... which is a good 17 times slower (and sometimes much worse) than even some complicated versions of using multiple CONVERTs.

It's the company that release SQL Server 2019 and 2022, which I've tested as being > 23% slower than SQL Server 2017 and that's just for code that only uses the CPU with no I/O.

And those are just a few of the things that have gone seriously "underpowered" or have actually caused damage.

And now they want to "bring back" mirroring? Why on Earth would anyone trust that they not simply going to take it away again in a couple years? Or, are they bringing it back because it will be profitable for them to do so on cloud hardware?

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

m60freeman SSC-Addicted Points: 445 More actions · Answer 2

Our issue with all the various ways to get changes from SQL Server into Synapse or Fabric is that deletes get ignored, so if someone (for example) adds a Project (which has lots of child tables linked by ProjectId), populates the tables, and then deletes that Project, we have to write our own process to get those rows out of the DW/DL which brings in all the overhead the new built-in tools avoid (periodically scanning the source tables).

Perry Whittle SSC Guru Points: 234013 More actions · Answer 3

It makes sense for azure sqldb, AGs are more targeted at groups of databases rather than single dbs, ok azure sqldb are pinned to a virtual instance for database connectivity but that’s really about it. You can’t context switch between azure sqldbs on the same instance.

Mirroring for single db likely has benefit of less required resource on the fabric.

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"Ya can't make an omelette without breaking just a few eggs" 😉

sqlrider SSC Enthusiast Points: 104 More actions · Answer 4

Jeff Moden wrote:

It's the company that release SQL Server 2019 and 2022, which I've tested as being > 23% slower than SQL Server 2017 and that's just for code that only uses the CPU with no I/O.

Hi Jeff, can you elaborate on that, or have you done a post/video on it?

https://sqlrider.net - My technical blog