This commit extends compatibility with the bbolt kvdb implementation,
which returns ErrIncompatibleValue in case of a bucket/value key
collision. Furthermore the commit also adds an extra precondition to the
transaction when a key doesn't exist. This is needed as we fix reads to
a snapshot revision and other writers may commit the key otherwise.
This commit removes the lock set which was used to only add bucket keys
to the tx predicate while also bumping their mod version.
This was useful to reduce the size of the compare set but wasn't useful
to reduce contention as top level buckets were always in the lock set.
This commit extends the etcd.BackendConfig to also provide an abort
context and integrates it with the STM retry loop in order to be able
stop LND when conflicting transactions keep the loop running.
This commit removes the retry goroutine from the STM as the retry loop
is only running when the STM transaction is encapsulated in Update/View
whereas for self-standing transactions we use a different approach.
By removing the goroutine we won't catch panics thrown that are supposed
to be catched outside of the STM.
This commit separates all etcd related sources (sans a few stubs and
config) from the rest of the source tree and makes compilation conditional
depending on whether the kvdb_etcd build tag is specified.
This commit reduces the compare set size the STM will submit in
transactions by adding only the bucket keys along the bucket path to a
specific lock set. This lock set then used to filter the read set,
effectively removing all read only keys from the transaction predicate
that are not bucket keys.
By tracking if a read-write tx actually changes something, we can also
"bump" the mod revision of the bucket keys.
With this trick we essentially implement a read-write lock for our
bucket structure greatly reducing transaction processing time.
This commit adds an extended STM, similar to what available in etcd's
clientv3 module. This incarnation of said STM supports additional
features, like positioning in key intervals while taking into account
deletes and writes as well. This is a preliminary work to support all
features of the kvdb interface.
