Extension:Cassandra

MediaWiki extensions manual - list

Cassandra Release status: experimental
Implementation	Database
Description	Allows to store revision text in Apache Cassandra NoSQL database
Author(s)	Max Semenik (MaxSemtalk)
MediaWiki	1.16+, may work on earlier version though not tested
PHP	5.2+
License	WTFPL 2.0
Download	Subversion [Help] Browse source code
Check usage and version matrix

What can this extension do?

This extension allows to offload revision text to Apache Cassandra, reducing the load on main database.

Download instructions

Download the extension from SVN and place it under $IP/extensions/Cassandra/. Note: $IP stands for the root directory of your MediaWiki installation, the same directory that holds LocalSettings.php.

Installation

1. Download and install Thrift and Cassandra using these instructions.
2. Build the Thrift to Cassandra bindings as explained in instructions above. If you're on Windows and can't build them, you can use files bundled with Cassandra in <cassandra path>/lib/. Copy them to <thrift root>/lib/php/src/packages/cassandra/.
3. Download this extension and put it to <MediaWiki root>/extensions/Cassandra/.
4. Add the following to LocalSettings.php:

require_once( "$IP/extensions/Cassandra/Cassandra.php" );
$wgThriftRoot = 'whatever directory your Thrift for PHP is installed';
# Configure external storage engines
$wgDefaultExternalStore = array( 'cassandra://<host>/<keyspace>' );

Where <host> is cluster name or host name of your Cassandra server (see $wgCassandraClusters below), and <keyspace> is keyspace (roughly, analog of "database" in traditional RDBMS terminology) to be used. See here for details on how $wgExternalStores works.

Configuration parameters

Name	Default value	Meaning
$wgThriftRoot	'/usr/share/php/Thrift'	Directory where Thrift bindings for PHP reside
$wgCassandraPort	9160	Port used for communicating with Cassandra. Must match <ThriftPort> in Cassandra's storage-conf.xml
$wgCassandraKeyPrefix	$wgDBname	String prepended to saved key names, can be used to distinct between different wikis, etc. Does not affect the already saved revisions.
$wgCassandraColumnFamily	'Standard1'	Column family to be used for storing data
$wgCassandraReadConsistency	1	Read consistency, see http://wiki.apache.org/cassandra/API#ConsistencyLevel
$wgCassandraWriteConsistency	1	Write consistency, see http://wiki.apache.org/cassandra/API#ConsistencyLevel
$wgCassandraClusters	array()	List of clusters and hosts belonging to them, for example: $wgCassandraClusters = array( 'foo' => array( '192.168.1.1', '192.168.1.2', ), 'bar' => array( 'somehostname' ), );