Class: JobQueueFederated  - X-Ref

Class to handle enqueueing and running of background jobs for federated queues

This class allows for queues to be partitioned into smaller queues.
A partition is defined by the configuration for a JobQueue instance.
For example, one can set $wgJobTypeConf['refreshLinks'] to point to a
JobQueueFederated instance, which itself would consist of three JobQueueRedis
instances, each using their own redis server. This would allow for the jobs
to be split (evenly or based on weights) accross multiple servers if a single
server becomes impractical or expensive. Different JobQueue classes can be mixed.

The basic queue configuration (e.g. "order", "claimTTL") of a federated queue
is inherited by the partition queues. Additional configuration defines what
section each wiki is in, what partition queues each section uses (and their weight),
and the JobQueue configuration for each partition. Some sections might only need a
single queue partition, like the sections for groups of small wikis.

If used for performance, then $wgMainCacheType should be set to memcached/redis.
Note that "fifo" cannot be used for the ordering, since the data is distributed.
One can still use "timestamp" instead, as in "roughly timestamp ordered". Also,
queue classes used by this should ignore down servers (with TTL) to avoid slowness.