Random thoughts on concurrency, databases and distributed systems

Andrei Pechkurov

Andrei Pechkurov

296 followers

Core database engineer at QuestDB. Distributed systems gazer. Node.js contributor. Occasional tech blogger and speaker.

Multithreaded Execution Model for Queries With ORDER BY and LIMIT Clauses

Jun 9, 2024

This small post continues the previous post dedicated to multithreaded query execution in databases with column-oriented storage format. This time...

Multithreaded Execution Model for Queries With ORDER BY and LIMIT Clauses

An mmap-based hash table optimization

Jun 1, 2024

mmap is a controversial topic among the database community. The common belief is that it's no good for a database, but in my experience, it does a...

An mmap-based hash table optimization

Seqlock-Based Atomic Memory Snapshots

Aug 6, 2023

Last time we discussed k-word CAS algorithm and came to the conclusion that seqlock-based atomic snapshots may be used as an alternative in situations...

Seqlock-Based Atomic Memory Snapshots

A Few Thoughts on K-Word CAS

Jul 6, 2023

A few months ago I went through Efficient Multi-word Compare and Swap paper, so here are a few thoughts on the algorithm. Long story short, I have...

A Few Thoughts on K-Word CAS

The Secret Life of fsync

Mar 31, 2023

Several times I've heard opinions that many mass-market SSDs and HDDs don't provide sufficient durability guarantees and Linux can do nothing with...

The Secret Life of fsync

Multithreaded Scatter-Gather Execution Model for Analytical Queries

Jan 14, 2023

Today we'll discuss an approach used in some analytical databases to speed up the execution of queries at the cost of additional HW resources, namely...

Multithreaded Scatter-Gather Execution Model for Analytical Queries