This commit modifies the composition of the boltdb pointer within the
DB struct to use embedding.
The rationale for this change is that the daemon may soon store some
semi-transient items within the database which requires us to expose
the boltdb’s transaction API. The logic for serialization of this data
will likely lie outside of the channeldb package as the items that may
be stored in the future will be specific to the current sub-systems
within the daemon and not generic channel related data.
This commit introduces a new method to channeldb: ‘FetchAllChannels’.
This method can be used to obtain the state of all active (currently
open) channels within the database. This method can be used for compute
basic channel-based metrics or exposed as an RPC in order to allow
clients to display/query channel data.
This commit adds a new bucket to the database which is dedicated to
storing data pertaining to p2p related reachability for direct channel
counter parties. The data stored in this new bucket can be used within
heuristics when deciding to unilaterally close a channel due to
inactivity. Additionally, all known reachable IP addresses for a
particular LinkNode are to be stored and updated within the database in
order to facilitate the establishment of persistent connections to
direct channel counter parties.
The state of OpenChannel on disk has now been partitioned into several
buckets+keys within the db. At the top level, a set of prefixed keys
stored common data updated frequently (with every channel update).
These fields are stored at the top level in order to facilities prefix
scans, and to avoid read/write amplification due to
serialization/deserialization with each read/write.
Within the active channel bucket, a nested bucket keyed on the node’s
ID stores the remainder of the channel.
Additionally OpenChannel now uses elkrem rather than shachain, delivery
scripts instead of addresses, stores the total net fees, and splits the
csv delay into the remote vs local node’s.
Several TODO’s have been left lingering, to be visited in the near
future.
* Initial draft of brain dump of chandler. Nothing yet set in stone.
* Will most likely move the storage of all structs to a more “column”
oriented approach. Such that, small updates like incrementing the total
satoshi sent don’t result in the entire struct being serialized and
written.
* Some skeleton structs for other possible data we might want to store
are also included.
* Seem valuable to record as much data as possible for record keeping,
visualization, debugging, etc. Will need to set up a time+space+dirty
cache to ensure performance isn’t impacted too much.
