We're happy to announce the release of RelStorage 3.0, the relational storage engine for ZODB. Compared to RelStorage 2, highlights include a 30% reduction in memory usage, and up to 98% faster performance! (Ok, yes, that's from one specific benchmark and not everything is 98% faster, but improved performance was a major goal.) RelStorage 3.0 is a major release of RelStorage with a focus on performance and scalability. It's the result of a concentrated development effort spanning six months, with each pre-release being in production usage with large databases. Read on to find out what's new.

Previously we talked about gevent's hub and how greenlets switch in and out of it to implement IO. This time, let's talk about how we can use those same primitives, plus the properties that make greenlets greenlets, to implement locks. We'll start by walking through some basics about locks and move on to how locks are used in Python when working with threads. All of that will be background for finally covering how gevent implements greenlet-based locks.

The hub is an important part of gevent, but aside from a few sentences in the high-level description of the event loop, and the API documentation, not a lot has been written about the hub, its purpose, or how it does what it does. This post aims to change that and answer questions like: What is the hub? How does the hub run the event loop? How do greenlets do IO? That is, how do they let the event loop run, while letting other greenlets run, and then pick right back up where they blocked?

Like any good blog, this one includes a post about what technologies power it.