nimbus-eth1/nimbus/db/aristo/aristo_layers.nim
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

267 lines
9.2 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/[enumerate, sequtils, sets, tables],
eth/common,
results,
./aristo_desc
# ------------------------------------------------------------------------------
# Private functions
# ------------------------------------------------------------------------------
func dup(sTab: Table[RootedVertexID,VertexRef]): Table[RootedVertexID,VertexRef] =
## Explicit dup for `VertexRef` values
for (k,v) in sTab.pairs:
result[k] = v.dup
# ------------------------------------------------------------------------------
# Public getters: lazy value lookup for read only versions
# ------------------------------------------------------------------------------
func vTop*(db: AristoDbRef): VertexID =
db.top.delta.vTop
# ------------------------------------------------------------------------------
# Public getters/helpers
# ------------------------------------------------------------------------------
func nLayersVtx*(db: AristoDbRef): int =
## Number of vertex ID/vertex entries on the cache layers. This is an upper
## bound for the number of effective vertex ID mappings held on the cache
## layers as there might be duplicate entries for the same vertex ID on
## different layers.
##
db.stack.mapIt(it.delta.sTab.len).foldl(a + b, db.top.delta.sTab.len)
func nLayersKey*(db: AristoDbRef): int =
## Number of vertex ID/key entries on the cache layers. This is an upper
## bound for the number of effective vertex ID mappingss held on the cache
## layers as there might be duplicate entries for the same vertex ID on
## different layers.
##
db.stack.mapIt(it.delta.kMap.len).foldl(a + b, db.top.delta.kMap.len)
# ------------------------------------------------------------------------------
# Public functions: getter variants
# ------------------------------------------------------------------------------
func layersGetVtx*(db: AristoDbRef; rvid: RootedVertexID): Opt[(VertexRef, int)] =
## Find a vertex on the cache layers. An `ok()` result might contain a
## `nil` vertex if it is stored on the cache that way.
##
db.top.delta.sTab.withValue(rvid, item):
return Opt.some((item[], 0))
for i, w in enumerate(db.rstack):
w.delta.sTab.withValue(rvid, item):
return Opt.some((item[], i + 1))
Opt.none((VertexRef, int))
func layersGetVtxOrVoid*(db: AristoDbRef; rvid: RootedVertexID): VertexRef =
## Simplified version of `layersGetVtx()`
db.layersGetVtx(rvid).valueOr((VertexRef(nil), 0))[0]
func layersGetKey*(db: AristoDbRef; rvid: RootedVertexID): Opt[(HashKey, int)] =
## Find a hash key on the cache layers. An `ok()` result might contain a void
## hash key if it is stored on the cache that way.
##
db.top.delta.kMap.withValue(rvid, item):
return Opt.some((item[], 0))
for i, w in enumerate(db.rstack):
w.delta.kMap.withValue(rvid, item):
return ok((item[], i + 1))
Opt.none((HashKey, int))
func layersGetKeyOrVoid*(db: AristoDbRef; rvid: RootedVertexID): HashKey =
## Simplified version of `layersGetKey()`
(db.layersGetKey(rvid).valueOr (VOID_HASH_KEY, 0))[0]
func layersGetAccLeaf*(db: AristoDbRef; accPath: Hash256): Opt[VertexRef] =
db.top.delta.accLeaves.withValue(accPath, item):
return Opt.some(item[])
for w in db.rstack:
w.delta.accLeaves.withValue(accPath, item):
return Opt.some(item[])
Opt.none(VertexRef)
func layersGetStoLeaf*(db: AristoDbRef; mixPath: Hash256): Opt[VertexRef] =
db.top.delta.stoLeaves.withValue(mixPath, item):
return Opt.some(item[])
for w in db.rstack:
w.delta.stoLeaves.withValue(mixPath, item):
return Opt.some(item[])
Opt.none(VertexRef)
# ------------------------------------------------------------------------------
# Public functions: setter variants
# ------------------------------------------------------------------------------
func layersPutVtx*(
db: AristoDbRef;
rvid: RootedVertexID;
vtx: VertexRef;
) =
## Store a (potentally empty) vertex on the top layer
db.top.delta.sTab[rvid] = vtx
func layersResVtx*(
db: AristoDbRef;
rvid: RootedVertexID;
) =
## Shortcut for `db.layersPutVtx(vid, VertexRef(nil))`. It is sort of the
## equivalent of a delete function.
db.layersPutVtx(rvid, VertexRef(nil))
func layersPutKey*(
db: AristoDbRef;
rvid: RootedVertexID;
key: HashKey;
) =
## Store a (potentally void) hash key on the top layer
db.top.delta.kMap[rvid] = key
func layersResKey*(db: AristoDbRef; rvid: RootedVertexID) =
## Shortcut for `db.layersPutKey(vid, VOID_HASH_KEY)`. It is sort of the
## equivalent of a delete function.
db.layersPutKey(rvid, VOID_HASH_KEY)
proc layersUpdateVtx*(
db: AristoDbRef; # Database, top layer
rvid: RootedVertexID;
vtx: VertexRef; # Vertex to add
) =
## Update a vertex at `rvid` and reset its associated key entry
db.layersPutVtx(rvid, vtx)
db.layersResKey(rvid)
func layersPutAccLeaf*(db: AristoDbRef; accPath: Hash256; leafVtx: VertexRef) =
db.top.delta.accLeaves[accPath] = leafVtx
func layersPutStoLeaf*(db: AristoDbRef; mixPath: Hash256; leafVtx: VertexRef) =
db.top.delta.stoLeaves[mixPath] = leafVtx
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
func layersMergeOnto*(src: LayerRef; trg: var LayerObj) =
## Merges the argument `src` into the argument `trg` and returns `trg`. For
## the result layer, the `txUid` value set to `0`.
##
trg.txUid = 0
for (vid,vtx) in src.delta.sTab.pairs:
trg.delta.sTab[vid] = vtx
for (vid,key) in src.delta.kMap.pairs:
trg.delta.kMap[vid] = key
trg.delta.vTop = src.delta.vTop
for (accPath,leafVtx) in src.delta.accLeaves.pairs:
trg.delta.accLeaves[accPath] = leafVtx
for (mixPath,leafVtx) in src.delta.stoLeaves.pairs:
trg.delta.stoLeaves[mixPath] = leafVtx
func layersCc*(db: AristoDbRef; level = high(int)): LayerRef =
## Provide a collapsed copy of layers up to a particular transaction level.
## If the `level` argument is too large, the maximum transaction level is
## returned. For the result layer, the `txUid` value set to `0`.
##
let layers = if db.stack.len <= level: db.stack & @[db.top]
else: db.stack[0 .. level]
# Set up initial layer (bottom layer)
result = LayerRef(
delta: LayerDeltaRef(
sTab: layers[0].delta.sTab.dup, # explicit dup for ref values
kMap: layers[0].delta.kMap,
vTop: layers[^1].delta.vTop,
accLeaves: layers[0].delta.accLeaves,
stoLeaves: layers[0].delta.stoLeaves,
))
# Consecutively merge other layers on top
for n in 1 ..< layers.len:
for (vid,vtx) in layers[n].delta.sTab.pairs:
result.delta.sTab[vid] = vtx
for (vid,key) in layers[n].delta.kMap.pairs:
result.delta.kMap[vid] = key
for (accPath,vtx) in layers[n].delta.accLeaves.pairs:
result.delta.accLeaves[accPath] = vtx
for (mixPath,vtx) in layers[n].delta.stoLeaves.pairs:
result.delta.stoLeaves[mixPath] = vtx
# ------------------------------------------------------------------------------
# Public iterators
# ------------------------------------------------------------------------------
iterator layersWalkVtx*(
db: AristoDbRef;
seen: var HashSet[VertexID];
): tuple[rvid: RootedVertexID, vtx: VertexRef] =
## Walk over all `(VertexID,VertexRef)` pairs on the cache layers. Note that
## entries are unsorted.
##
## The argument `seen` collects a set of all visited vertex IDs including
## the one with a zero vertex which are othewise skipped by the iterator.
## The `seen` argument must not be modified while the iterator is active.
##
for (rvid,vtx) in db.top.delta.sTab.pairs:
yield (rvid,vtx)
seen.incl rvid.vid
for w in db.rstack:
for (rvid,vtx) in w.delta.sTab.pairs:
if rvid.vid notin seen:
yield (rvid,vtx)
seen.incl rvid.vid
iterator layersWalkVtx*(
db: AristoDbRef;
): tuple[rvid: RootedVertexID, vtx: VertexRef] =
## Variant of `layersWalkVtx()`.
var seen: HashSet[VertexID]
for (rvid,vtx) in db.layersWalkVtx seen:
yield (rvid,vtx)
iterator layersWalkKey*(
db: AristoDbRef;
): tuple[rvid: RootedVertexID, key: HashKey] =
## Walk over all `(VertexID,HashKey)` pairs on the cache layers. Note that
## entries are unsorted.
var seen: HashSet[VertexID]
for (rvid,key) in db.top.delta.kMap.pairs:
yield (rvid,key)
seen.incl rvid.vid
for w in db.rstack:
for (rvid,key) in w.delta.kMap.pairs:
if rvid.vid notin seen:
yield (rvid,key)
seen.incl rvid.vid
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------