Manual:$wgMainStash

Cache: $wgMainStash
Replicated object cache setting
Introduced in version:	1.26.0 (Gerrit change 207718; git #793d0140)
Removed in version:	Still in use
Allowed values:	One of the CACHE constants (see $wgMainCacheType )
Default value:	CACHE_DB (1.42+) 'db-replicated' (1.26-1.41)
Other settings: Alphabetical | By function

Details

This setting controls the cache used by methods that store temporary values that need to be seen in all datacenters. This is not true of $wgMainCacheType , which should be a fast and local-only cache. Ideally, a better effort should be made to reduce evictions are data loss during power outages that main cache stores (e.g. redis with disk-persistence enabled and allkeys-lru). Nevertheless, the store does not need to be a robust ACID compliant database, it should merely be a fast, memory-based, store that replicates data to all sites. A modest amount of eviction or lost data (such as on fail-over) can be tolerated.