ctrie-java VS asami

Concurrent tries with non-blocking snapshots [0]

Say that you have a dataset that needs to be ordered, easily searchable, but is also updated quite frequently. Fast accesses are a pain if you decide to use traditional read-write locks.

Ctries are entirely lock-free, thus there is no waiting for your read operations when an update is happening, i.e. you run lookups on snapshots while updates happen.

They are also a lot of fun to implement, especially if you aren't familiar with lock-free algorithms! I did learn a lot doing it myself [1]

[0] http://aleksandar-prokopec.com/resources/docs/ctries-snapsho...

[1] https://github.com/mabeledo/ctrie-java

Unlike some other commenters, I agree that graph models are usually a better fit for most data than relational models. There's been some interesting work in recent years developing this idea: in the Clojure world there's Datomic, XTDB, and a host of competitors, all of which build on work from Semantic Web/SPARQL/triplestores and logic programming. Some are even intended to be used as primary datastores: they support some amount of schema and constraints, have well-defined consistency and ACID guarantees, etc. This makes them unlike graph databases like Neo4J and others, which fill an architectural role more like Elasticsearch as a read-optimization tool. Here's an interesting talk making a case for triple-based databases.

Despite the documentation that exists, I've heard many people who have been confused about how to query Datomic, Datascript, Asami, or other graph databases. So I've made an attempt at explaining it https://github.com/threatgrid/asami/wiki/Introduction

The first Graph implementation for Asami was a simple in-memory data structure, described in my ClojureD talk. The code for this appears in asami.index. This file started much smaller (as referenced above), but has since expanded with the needs extended functionality, such as transactions, and transitive closure operations.