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Day: October 21, 2026

Entry Points and Graph Neighborhoods with DiskANN

Published 2026-10-21 by Kevin Feasel

Mala Mahadevan tries something out:

I was experimenting with vector search in SQL Server 2025 using approximately 3.8 million Hacker News articles that that I used for my talk on SQL Server-based vector search feature at EightKB. I generated two sets of embeddings from the same articles: one stored as FP32 (32-bit floating point) and the other as FP16 (16-bit floating point). Both sets contained the same articles and used DiskANN vector indexes.I used a query as below to find articles similar to a selected example.

What Mala found was that FP16 queries could sometimes take longer and require more reads than FP32 queries, which doesn’t make sense on its face. Click through to see two experiments she devised to come up with the answer.

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Clock Changes and SQL Server

Published 2026-10-21 by Kevin Feasel

Dualcore DBA turns back time:

In this post we’ll look at the behaviour of a SQL Server application that needs to deal with events that are logged over the period of a UK clock change where the clocks change from GMT (Greenwich Mean Time) to BST (British Summer Time).

The data itself is in UTC (which is good), but getting from UTC to the user’s local time can be a major challenge, especially in T-SQL. There are application libraries that make this a lot easier, which is why I recommend bouncing this up to the application layer whenever possible.

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Lessons Learned from Troubleshooting with LLMs

Published 2026-10-21 by Kevin Feasel

Grant Fritchey spends a weekend:

Grant Fritchey walks through a real troubleshooting saga – using Wine, a shim DLL, a misconfigured registry entry, and a lot of trial and error – to get a BridgeCom Maverick radio’s Windows CPS running on Linux Mint.

Along the way, repeated dead ends revealed a pattern: AI tools stay locked onto whatever direction you last pointed them, and it’s up to you to redirect, request alternatives, and demand measurement over guesswork.

In this article, Grant shares everything he learned from the experience, including 8 key takeaways to help you avoid similar trouble when using AI in the future.

Grant takes us through the story and shares eight tips for better troubleshooting along the way. Oh, and Wine is notoriously finicky, so I can totally get why it’d take a while to sort out the issues Grant had.

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Auto-Indexing in SQL Server

Published 2026-10-21 by Kevin Feasel

Brent Ozar unveils a secret:

It’s super simple: the installation file, AutoIndex.sql, creates an Agent job and a series of stored procedures including auto_create_index and auto_drop_index. They watch the index usage and missing index DMVs, log their findings to tables, and trend the data over time in order to figure out which indexes to create, and which ones to prune back because they’re only slowing you down.

And it’s even free!

I enjoy these posts, where Brent goes back to ideas people had 20+ years ago. It really shows how creative the SQL Server development team was back in the day.

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XACT_ABORT vs TRY_CATCH

Published 2026-10-21 by Kevin Feasel

Jared Westover explains the difference:

After creating a SQL script and a pull request, a savvy developer left a comment on the PR because they were confused about why I was using both XACT_ABORT and TRY…CATCH. They thought that including both in one script was redundant. That got me thinking: is it true that setting XACT_ABORT ON makes TRY…CATCH redundant?

The most interesting part of this post is the cases in which you would use both in the same script.

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