Morph "NewEpoch" event handling was registered in a closure over
`addNewEpochNotificationHandler` func. That may lead to the data race:
if a shard was initialized before the event registration, everything works
as planned, but if registration was made earlier, it was not able to
include GC handlers since a shard has not called `eventChanInit` yet and,
therefore, it has not registered handler yet.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
There is a need to process expired `LOCK` objects similar to `TOMBSTONE`
ones: we collect them on `Shard`, notify all other shards about
expiration so they could unlock the objects, and only after that mark
lockers as garbage.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Provide shard mode information via `DumpInfo()`. Delete atomic field from
Shard structure since it duplicates new field.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Add new epoch event handler to GC that finds all expired tombstones and
marks them and underlying objects to be removed. Shard uses callbacks
provided by the storage engine to mark underlying objects.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Shard's GC component consists of:
* asynchronous remover that periodically wake up and removes all garbage
objects from the shard, and goes to sleep for particular time interval;
* external event listener that distributes jobs between workers;
* group of workers that can handle a single job related to particular
external event.
Remover and event listener represents go-routines which are started by
`init` method (calls from `Shard.Init`). In initial version all event
handlers are interrupted: this means that next event of the same type will
interrupt previous handling and start the new one.
GC is fully encapsulated in Shard. All GC configurations are reflected in
Shard's configuration.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In previous implementation each shard operation locked
RW shard mutex. With this approach RW operations were executed
one-by-one and blocked the execution of RO operations.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
