It allows storing information about object in both ways at the same time:
1. Metabase should know if an object is covered by a tombstone (that is
not expired yet);
2. It should be possible to physically delete objects covered by a
tombstone immediately (mark with GC) but keep tombstone knowledge.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
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>
`Degraded` mode is set automatically after error counter is over the
threshold. `ReadOnly` mode can still be set by an administrator.
Signed-off-by: Evgenii Stratonikov <evgeniy@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>
Use `sync.Once` to prevent locks of stopping GC. It will also allow to
safely call `Shard.Close` multiple times.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Some of the pools are initialized during config initialization,
so it isn't possible currently to release them in one place.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Change Shard's garbage remover to interrupt iterating over the metabase
graveyard when the buffer is full to the max size (`WithRemoverBatchSize`
Shard's option).
Signed-off-by: Leonard Lyubich <leonard@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>
Add new epoch event handler to GC that finds all expired non-tombstone
objects and marks them to be removed.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Group handlers of the particular event to a WaitGroup and wait for it before
the next event handling. This will ensure that all handlers complete and
prevent potential conflicts between past and present jobs.
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>
