The query optimizer in ArangoDB 2.8 has been improved in terms of how it can make use of indexes. In previous versions of ArangoDB, the query optimizer could use only one index per collection used in an AQL query. When using a logical OR in a FILTER condition, the optimizer did not use any index for the collection in order to ensure the result is still correct.

This is much better in 2.8. Now the query optimizer can use multiple indexes on the same collection for FILTER conditions that are combined with a logical OR.

For all following queries, I have set up a collection named test, which has..

The upcoming 2.8 version of ArangoDB will provide several improvements in the area of index usage and query optimization.

First of all, hash and skiplist indexes can now index individual array values. A dedicated post on this will follow shortly. Second, the query optimizer can make use multiple indexes per collection for queries with OR-combined filter conditions. This again is a subject for another post. Third, there have been some speed improvements due to changes in the general index handling code. This is what this post is about.

In order to assess the speedups in 2.8, I have run some..

The upcoming ArangoDB version 2.8 (currently in devel) will provide a much better deadlock detection mechanism than its predecessors.

The new deadlock detection mechanism will kick in automatically when it detects operations that are mutually waiting for each other. In case it finds such deadlock, it will abort one of the operations so that the others can continue and overall progress can be made.

In previous versions of ArangoDB, deadlocks could make operations wait forever, requiring the server to be stopped and restarted.

How deadlocks can occur

Here’s a simple example for getting into a..

The AQL editor in the web interface is useful for running ad hoc AQL queries and trying things out. It provides a feature to explain the query and inspect its execution plan. This can be used to check if the query uses indexes, and which.

So far the AQL editor only supported using query string literals, but it lacked support for bind parameters. Queries issued by application code however often will use bind parameters for security reasons. Often enough this prevented copying & pasting queries from the application code into the AQL editor and vice versa without making manual adjustments.

While preparing the release of ArangoDB 2.7, some improvements were made for the PHP driver for ArangoDB.

The 2.7 version of the PHP driver now supports the AQL query results cache. The cache can be turned on or off globally, or be set to demand mode. The demand mode will allow controlling caching on a per-AQL-query basis.

I recently wrote two recipes about generating AQL query strings. They are contained in the ArangoDB cookbook by now:

• Avoiding parameter injection in AQL
• Writing multi-line AQL queries

After that, Github user tracker1 suggested in Github issue 1457 to take the ES6 template string variant even further, using a generator function for string building, and also using promises and ES7 async/await.

We can’t use ES7 async/await in ArangoDB at the moment due to lacking support in V8, but the suggested template string generator function seemed to be an obvious improvement that deserved inclusion in..

We’ve recently been working on improving ArangoDB’s throughput, especially when using the ArangoDB’s interface.

In this post, I will show some of the improvements already achieved, though the work is not yet finished. Therefore, the results shown here are still somewhat preliminary.

We wanted to measure improvements for ArangoDB’s HTTP interface, and so we used wrk as an external HTTP load generator.

During the tests, wrk called some specific URLs on a local ArangoDB instance on an otherwise idle machine. The test was run with ArangoDB 2.6 and devel. The ArangoDB instances were started with..

ArangoDB allows running user-defined JavaScript code in the database. This can be used for more complex, stored procedures-like database operations. Additionally, ArangoDB’s Foxx framework can be used to make any database functionality available via an HTTP REST API. It’s easy to build data-centric microservices with it, using the scripting functionality for tasks like access control, data validation, sanitation etc.

We often get asked how the scripting functionality is implemented under the hood. Additionally, several people have asked how ArangoDB’s JavaScript functionality relates to..

ArangoDB’s devel branch recently saw a change that makes writing some AQL queries a bit simpler.

The change introduces an optional shorthand notation for object attributes in the style of ES6’s enhanced object literal notation.

Last week saw the addition of the RETURN DISTINCT for AQL queries. This is a new shortcut syntax for making result sets unique.

For this purpose it can be used as an easier-to-memorize alternative for the already existing COLLECT statement. COLLECT is very flexible and can be used for multiple purposes, but it is syntactic overkill for making a result-set unique.