relstorage.cache.mvcc – MVCC tracking for cache objects#

MVCC tracking for cache objects.

class MVCCDatabaseCoordinator(options=None)[source]#

Bases: DetachableMVCCDatabaseCoordinator

Keeps track of the most recent polling data so that instances don’t make unnecessary polls.

Shared between all instances of a StorageCache in a tree, from the master down.


The maximum amount of time, in seconds, we will spend polling the database for OIDS when restoring the cache. If this time is exceeded, we will only partially use the cache. This is not set by default because doing so introduces a slight speed penalty to the polling process.