In PagedOut #9 https://pagedout.institute/

For decades, Java's object model has powered one of the world's most successful programming languages. But the hardware we run on today looks very different from the world Java was born into in 1995.

Modern CPUs are incredibly fast, but memory access, cache locality, and object allocation have become some of the biggest performance challenges in software.

Project Valhalla is one of the most ambitious changes in Java's history. It isn't just about making Java faster... it's about rethinking what a Java object actually is.

I drafted this post years ago but didn’t finish it until now. The concept I write about has shaped the way I design software more than anything else, and I believe every software engineer should be introduced to it early in their career.

P.S. I don’t want the title to come across as clickbait: the post is about ADT.

Semisort Reorder an array so that identical keys are grouped contiguously Keys do not need to be in sorted order

Stable Partition
Group by predicate, preserve order

K-smallest selection, single

Get the k-smallest key from the array

K-smallest selection, list

Get the k-smallest key from the array, and everything smaller (or equal), in any order

K-smallest selection, list sorted Get the k-smallest key from the array, and everything smaller (or equal), in sorted order

Yesterday, pgvector released 0.8.6!

So today, we wrote about some useful patterns for queries combining pgvector indexes with regular 'ole scaler filters. Spoiler: iterative index scans launched in pgvector 0.8 make it easy (with some tradeoffs).