nimbus-eth1/nimbus/db/kvt/kvt_init/persistent.nim
Jordan Hrycaj cd1d370543
Aristo db api extensions for use as core db backend (#1754)
* Update docu

* Update Aristo/Kvt constructor prototype

why:
  Previous version used an `enum` value to indicate what backend is to
  be used. This was replaced by using the backend object type.

* Rewrite `hikeUp()` return code into `Result[Hike,(Hike,AristoError)]`

why:
  Better code maintenance. Previously, the `Hike` object was returned. It
  had an internal error field so partial success was also available on
  a failure. This error field has been removed.

* Use `openArray[byte]` rather than `Blob` in functions prototypes

* Provide synchronised multi instance transactions

why:
  The `CoreDB` object was geared towards the legacy DB which used a single
  transaction for the key-value backend DB. Different state roots are
  provided by the backend database, so all instances work directly on the
  same backend.

  Aristo db instances have different in-memory mappings (aka different
  state roots) and the transactions are on top of there mappings. So each
  instance might run different transactions.

  Multi instance transactions are a compromise to converge towards the
  legacy behaviour. The synchronised transactions span over all instances
  available at the time when base transaction was opened. Instances
  created later are unaffected.

* Provide key-value pair database iterator

why:
  Needed in `CoreDB` for `replicate()` emulation

also:
  Some update of internal code

* Extend API (i.e. prototype variants)

why:
  Needed for `CoreDB` geared towards the legacy backend which has a more
  basic API than Aristo.
2023-09-15 16:23:53 +01:00

51 lines
1.7 KiB
Nim

# nimbus-eth1
# Copyright (c) 2021 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
# http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
# http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed
# except according to those terms.
## Persistent constructor for Kvt DB
## ====================================
##
## This module automatically pulls in the persistent backend library at the
## linking stage (e.g. `rocksdb`) which can be avoided for pure memory DB
## applications by importing `./kvt_init/memory_only` (rather than
## `./kvt_init/persistent`.)
##
{.push raises: [].}
import
results,
../kvt_desc,
"."/[rocks_db, memory_only]
export
RdbBackendRef,
memory_only
# ------------------------------------------------------------------------------
# Public database constuctors, destructor
# ------------------------------------------------------------------------------
proc init*[W: MemOnlyBackend|RdbBackendRef](
T: type KvtDbRef;
B: type W;
basePath: string;
): Result[KvtDbRef,KvtError] =
## Generic constructor, `basePath` argument is ignored for `BackendNone` and
## `BackendMemory` type backend database. Also, both of these backends
## aways succeed initialising.
##
when B is RdbBackendRef:
ok KvtDbRef(top: LayerRef(vGen: vGen), backend: ? rocksDbBackend basePath)
else:
ok KvtDbRef.init B
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------