Jacek Sieka df4a21c910
Store cached hash at the layer corresponding to the source data (#2492)
When lazily verifying state roots, we may end up with an entire state
without roots that gets computed for the whole database - in the current
design, that would result in hashes for the entire trie being held in
memory.

Since the hash depends only on the data in the vertex, we can store it
directly at the top-most level derived from the verticies it depends on
- be that memory or database - this makes the memory usage broadly
linear with respect to the already-existing in-memory change set stored
in the layers.

It also ensures that if we have multiple forks in memory, hashes get
cached in the correct layer maximising reuse between forks.

The same layer numbering scheme as elsewhere is reused, where -2 is the
backend, -1 is the balancer, then 0+ is the top of the stack and stack.

A downside of this approach is that we create many small batches - a
future improvement could be to collect all such writes in a single
batch, though the memory profile of this approach should be examined
first (where is the batch kept, exactly?).
2024-07-18 09:13:56 +02:00

114 lines
3.8 KiB
Nim

# nimbus-eth1
# Copyright (c) 2023-2024 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.
{.push raises: [].}
import
std/[sets, tables],
eth/common,
results,
stew/interval_set,
../../aristo,
../aristo_walk/persistent,
".."/[aristo_desc, aristo_get, aristo_layers]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc checkBE*[T: RdbBackendRef|MemBackendRef|VoidBackendRef](
_: type T;
db: AristoDbRef; # Database, top layer
): Result[void,(VertexID,AristoError)] =
## Make sure that each vertex has a Merkle hash and vice versa. Also check
## the vertex ID generator state.
var topVidBe: RootedVertexID = (VertexID(0), VertexID(0))
for (rvid,vtx) in T.walkVtxBe db:
if topVidBe.vid < rvid.vid:
topVidBe = rvid
if not vtx.isValid:
return err((rvid.vid,CheckBeVtxInvalid))
case vtx.vType:
of Leaf:
discard
of Branch:
block check42Links:
var seen = false
for n in 0 .. 15:
if vtx.bVid[n].isValid:
if seen:
break check42Links
seen = true
return err((rvid.vid,CheckBeVtxBranchLinksMissing))
for (rvid,key) in T.walkKeyBe db:
if topVidBe.vid < rvid.vid:
topVidBe = rvid
let vtx = db.getVtxBE(rvid).valueOr:
return err((rvid.vid,CheckBeVtxMissing))
# Compare calculated `vTop` against database state
# TODO
# if topVidBe.isValid:
# let vidTuvBe = block:
# let rc = db.getTuvBE()
# if rc.isOk:
# rc.value
# elif rc.error == GetTuvNotFound:
# VertexID(0)
# else:
# return err((VertexID(0),rc.error))
# if vidTuvBe != topVidBe:
# # All vertices and keys between `topVidBe` and `vidTuvBe` must have
# # been deleted.
# for vid in max(topVidBe + 1, VertexID(LEAST_FREE_VID)) .. vidTuvBe:
# if db.getVtxBE(vid).isOk or db.getKeyBE(vid).isOk:
# return err((vid,CheckBeGarbledVTop))
# Check layer cache against backend
block:
var topVidCache: RootedVertexID = (VertexID(0), VertexID(0))
# Check structural table
for (rvid,vtx) in db.layersWalkVtx:
if vtx.isValid and topVidCache.vid < rvid.vid:
topVidCache = rvid
let (key, _) = db.layersGetKey(rvid).valueOr: (VOID_HASH_KEY, 0)
if not vtx.isValid:
# Some vertex is to be deleted, the key must be empty
if key.isValid:
return err((rvid.vid,CheckBeCacheKeyNonEmpty))
# Check key table
var list: seq[RootedVertexID]
for (rvid,key) in db.layersWalkKey:
if key.isValid and topVidCache.vid < rvid.vid:
topVidCache = rvid
list.add rvid
let vtx = db.getVtx rvid
if db.layersGetVtx(rvid).isErr and not vtx.isValid:
return err((rvid.vid,CheckBeCacheKeyDangling))
# Check vTop
# TODO
# if topVidCache.isValid and topVidCache != db.vTop:
# # All vertices and keys between `topVidCache` and `db.vTop` must have
# # been deleted.
# for vid in max(db.vTop + 1, VertexID(LEAST_FREE_VID)) .. topVidCache:
# if db.layersGetVtxOrVoid(vid).isValid or
# db.layersGetKeyOrVoid(vid).isValid:
# return err((db.vTop,CheckBeCacheGarbledVTop))
ok()
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------