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Day: August 22, 2024

Data Integrity and the LIKE Operator

Joe Celko provides some context:

The LIKE operator has been in SQL since the very beginning. It’s a very weak form of pattern matching, that has only two simple wildcards. The wildcards are ‘_‘ (underscore) and ‘%‘ (percent). They respectively stand for any single character and for zero or more characters in a substring. The syntax is pretty straightforward:

Read on for examples of LIKE in action, including in check constraints.

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Cost Threshold for Parallelism and Missing Indexes

Jared Westover explains a phenomenon:

Did you know that the Cost Threshold for Parallelism (CTFP) affects SQL Server’s choice of a trivial execution plan? One area that can suffer from this setting is the optimizer’s ability to suggest index recommendations. When SQL Server picks a trivial plan, it skips suggesting any missing indexes. So, if you’ve set a high CTFP and run simple queries, you might never get those handy index recommendations.

Click through to learn more.

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Rating a Dashboard

Martin Schoombee explains the challenge of dashboard review:

A little while ago I was asked to rate a Power BI dashboard. The person who asked, participated in a Power BI challenge (I’ll call it that because that’s the way they are being marketed) and wanted some feedback on the submission. I agreed on the condition that the feedback would be public and in the form of a blog post.

Martin has a thoughtful explanation of the difficulty of providing a review (especially without important context around what the end users intend to do) but then does yeoman’s work talking about the visuals.

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Always Encrypted and Key Vault

Rod Edwards starts a series on Always Encrypted:

For the purposes of this post, i’m going to show how to set up Always Encrypted for column data held in an OnPrem SQL Server (which could be MI, or Azure SQL DB ) using keys stored in Azure Key Vault. And showing you some of the many potential issues that you need to be aware of along the way.

I’m not going to talk about the Secure Enclaves flavour here, just the ‘common or garden’ Always Encrypted.

Read on to learn more.

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Authentication Monitoring in Postgres

Rafia Sabih announces a new extension:

How about a situation when you want to log all the login attempts made to your PostgreSQL server. Yes, one way would be to read your log files and find out all the information related to login attempts and then transfer to them some other file, etc. to further use this information. Now, this is one way of doing it but it might pose some challenges like time and memory consumption in reading from those long files, additionally this is going to incur a lot of I/O which might be a serious issue when you are on cloud. During my time working for Zalando, we came across this problem and decided to write a Postgres extension to handle this efficiently.

Click through to learn more about the pg_auth_mon extension and how it works, including a link to the GitHub repository.

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