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Enhanced AQL in ArangoDB 2.4: Boost Query Performance
While on a retreat in Belgium, we found some spare time to work on improvements for AQL. These will be shipped with ArangoDB version 2.4, and are already available in the devel version for testing from now on.
Here’s a short overview of the improvements:
Collect with count
A common use case in query languages is to count the number of documents returned by a query. The AQL solution for this has been to use the LENGTH function and a subquery:
RETURN LENGTH((
FOR doc IN collection
FILTER doc.someAttribute == someValue
RETURN doc
))
This is quite long and probably unintuitive for people which have used SQL for years.
We therefore now allow using the following alternative version:
Weekly Newsletter – December 11, 2014 | ArangoDB Updates
ArangoDB Release
We released ArangoDB 2.3.2 with some bug fixes. You can find a full list of changes in our change-log. Here is a short extract:
- added AQL optimizer rule for removing INTO from a COLLECT statement if not needed
- fixed missing makeDirectory when fetching a Foxx application from a zip file
- fixed issue #1173: AQL Editor “Save current query” resets user password
ArangoDB related (Drivers & more)
- ArangoPy 0.5.3 (Python): Sascha Häusler has updated the Python driver so it is compatible with 2.3
- ansible-arangodb 1.0.0: Patrick Huber made an install helper, in this case Ansible-Galaxy. Ansible is an IT automation tool. It can configure systems, deploy software, and orchestrate more advanced IT tasks such as continuous deployments or zero downtime rolling updates
Documentation and Cookbook
- Joins in AQL: How to join documents from several collections. Thanks to Frank Celler
ArangoDB 2.3.2 Release: Enhancements & Bug Fixes
This version is deprecated. Download the new version of ArangoDB
A maintenance release for ArangoDB 2.3 is available for download or via your favourite package manager.
v2.3.2 (2014-12-09)
-------------------
* fixed issue #1173: AQL Editor "Save current query" resets user password
* fixed missing makeDirectory when fetching a Foxx application from a zip file
* put in warning about default changed: fixed issue #1134: Change the default endpoint to localhost
* fixed issue #1163: invalid fullCount value returned from AQL
* fixed range operator precedence
* limit default maximum number of plans created by AQL optimizer to 256 (from 1024)
* make AQL optimizer not generate an extra plan if an index can be used, but modify
existing plans in place
* fixed AQL cursor ttl (time-to-live) issue
Any user-specified cursor ttl value was not honored since 2.3.0.
* fixed segfault in AQL query hash index setup with unknown shapes
* fixed memleaks
* added AQL optimizer rule for removing `INTO` from a `COLLECT` statement if not needed
* fixed issue #1131
This change provides the `KEEP` clause for `COLLECT ... INTO`. The `KEEP` clause
allows controlling which variables will be kept in the variable created by `INTO`.
* fixed issue #1147, must protect dispatcher ID for etcd
Building Hypermedia APIs with FoxxGenerator: ArangoDB Tutorial
This is the third and final part of Lucas blog series about building hypermedia APIs. In the previous part, we identified the needed transitions and collected some information about each of them. Begin with blog post one to get familiar with concepts on Hypermedia and JSON.
We can now describe the identified transitions using FoxxGenerator. To make the most common case simple, it defaults to the type follow. Therefore defining our four follow transitions is easy using FoxxGenerator:
generator.defineTransition('books');
generator.defineTransition('users');
generator.defineTransition('item');
generator.defineTransition('likes');
Note that at this point we are just defining the transitions, we are not adding them to the statemachine we are describing with the help of FoxxGenerator. In the case of creating a book, we need to add additional information. First of, it is a connect transition. Secondly we also need to define the parameters that this transition needs:
generator.defineTransition('createBook', {
type: 'connect',
parameters: {
title: Joi.string()
}
});
Building Hypermedia APIs: Design Principles & Best Practices
This is the second blog post on building hypermedia APIs with the focus on API design. In part 1 Lucas describes the concept of links in JSON.
Imagine we have an API where people can like books and other people can then see, who likes a certain book. We want this API to be highly connected: We don’t want to look up URLs in a documentation, we want to follow links as we know it from the world wide web. All we want to do as the author of the API is give our users a single URL from which they can then follow links to all other resources. This is similar to the way we would do this with a website. Leonard Richardson and Mike Amundsen refer to this as the billboard URL for this reason: If you put this URL on some billboard, people know everything to get started with your API. (more…)
November Recap: ArangoDB Updates & Highlights
November 2014 was a month where our staff (and the cute ArangoDB Foxx) collected lot’s of miles by visiting conferences, meetups and inspiring people in Europe, Africa, the US and Canada. If you missed a talk, there are plenty of slideshares / recordings available.
Release 2.3
Everyone who was not on a plane worked on ArangoDB 2.3 – our major release with a re-written query optimizer that optimizes execution plans, added/improved AQL functions and several performance improvements (@see Query Optimizer Tour by Jan). You can download ArangoDB 2.3.1 and start optimizing.
Frank added a docker file, so you might start shipping ArangoDB in a docker container as well. (more…)
ArangoDB 2.3.1 Release: Enhancements & Bug Fixes
This version is deprecated. Download the new version of ArangoDB
A maintenance release for ArangoDB 2.3 is available from our download page and through the package manager.
- recreate password if missing during upgrade
- fixed issue #1126
- fixed non-working subquery index optimizations
- do not restrict summary of Foxx applications to 60 characters
- fixed display of “required” path parameters in Foxx application documentation
- added more optimizations of constants values in AQL FILTER conditions
- fixed invalid or-to-in optimization for FILTERs containing comparisons with boolean values
- fixed replication of
_graphscollection - added AQL list functions
PUSH,POP,UNSHIFT,SHIFT,REMOVE_VALUES,REMOVE_VALUE,REMOVE_NTHandAPPEND - added AQL functions
CALLandAPPLYto dynamically call other functions - fixed AQL optimizer cost estimation for LIMIT node
- prevent Foxx queues from permanently writing to the journal even when server is idle
- fixed AQL COLLECT statement with INTO clause, which copied more variables than v2.2 and thus lead to too much memory consumption. This deals with #1107.
- fixed AQL COLLECT statement, this concerned every COLLECT statement, only the first group had access to the values of the variables before the COLLECT statement. This deals with #1127.
- fixed some AQL internals, where sometimes too many items were fetched from upstream in the presence of a LIMIT clause. This should generally improve performance.
Building a Hypermedia API with JSON: ArangoDB Tutorial
When we create websites we don’t just create single pages that have no connection to other Web pages. From the beginning, hyperlinks were part of the core concept of the World Wide Web and for that reason HTML. Links are so essential to the Web that they are even used to rank the popularity of the Web pages on search engines. And who hasn’t gone on a journey through Wikipedia clicking link after link? Even though we all know and appreciate the importance of links on Websites, we rarely use links in our Web APIs. (more…)
Running ArangoDB Made Simple: Step-by-Step Guide
docker run -p 8529:8529 arangodb/arangodb
I’ve created an automated build repository on docker, so that you can easily start a docker container with the latest stable release. If you miss anything in the container, please let me know. Thanks to frodenas, hipertracker, joaodubas, webwurst who also created dockerfiles.
ArangoDB
A distributed open-source database with a flexible data model for documents, graphs, and key-values. Build high performance applications using a convenient sql-like query language or JavaScript extensions.
Start a ArangoDB instance
In order to start an ArangoDB instance run
unix> docker run --name arangodb-instance -d arangodb/arangodb
By default ArangoDB listen on port 8529 for request and the image includes EXPOST 8529. If you link an application container, it is automatically available in the linked container. See the following examples. (more…)
ArangoDB 2.2.7 Release: Enhancements & Bug Fixes
This version is deprecated. Download the new version of ArangoDB
A maintenance release for ArangoDB 2.2 is available from the usual channels.
v2.2.7 (2014-11-19)
- fixed issue #1079: AQL editor: keyword WITH in UPDATE query is not highlighted
- fix memory leak in cluster nodes
- fixed registration of AQL user-defined functions in Web UI (JS shell)
- fixed error display in Web UI for certain errors (now error message is printed instead of ‘undefined’)
- fixed issue #1059: bug in js module console
- fixed issue #1056: “fs”: zip functions fail with passwords
- fixed issue #1063: Docs: measuring unit of –wal.logfile-size?
- fixed issue #1062: Docs: typo in 14.2 Example data
The 2.2.7 Documentation: Click here
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