nimbus-eth1/nimbus/db/aristo/aristo_delete.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

338 lines
10 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.
## Aristo DB -- Patricia Trie delete funcionality
## ==============================================
##
## Delete by `Hike` type chain of vertices.
{.push raises: [].}
import
std/typetraits,
eth/common,
results,
"."/[aristo_desc, aristo_fetch, aristo_get, aristo_hike, aristo_layers,
aristo_utils, aristo_vid]
# ------------------------------------------------------------------------------
# Private heplers
# ------------------------------------------------------------------------------
proc branchStillNeeded(vtx: VertexRef): Result[int,void] =
## Returns the nibble if there is only one reference left.
var nibble = -1
for n in 0 .. 15:
if vtx.bVid[n].isValid:
if 0 <= nibble:
return ok(-1)
nibble = n
if 0 <= nibble:
return ok(nibble)
# Oops, degenerated branch node
err()
# -----------
proc disposeOfVtx(
db: AristoDbRef; # Database, top layer
rvid: RootedVertexID; # Vertex ID to clear
) =
# Remove entry
db.layersResVtx(rvid)
db.layersResKey(rvid)
db.vidDispose rvid.vid # Recycle ID
# ------------------------------------------------------------------------------
# Private functions
# ------------------------------------------------------------------------------
proc delSubTreeImpl(
db: AristoDbRef; # Database, top layer
root: VertexID; # Root vertex
): Result[void,AristoError] =
## Implementation of *delete* sub-trie.
var
dispose = @[root]
(rootVtx, _) = db.getVtxRc((root, root)).valueOr:
if error == GetVtxNotFound:
return ok()
return err(error)
follow = @[rootVtx]
# Collect list of nodes to delete
while 0 < follow.len:
var redo: seq[VertexRef]
for vtx in follow:
for vid in vtx.subVids:
# Exiting here leaves the tree as-is
let vtx = (? db.getVtxRc((root, vid)))[0]
redo.add vtx
dispose.add vid
redo.swap follow
# Mark collected vertices to be deleted
for vid in dispose:
db.disposeOfVtx((root, vid))
ok()
proc delStoTreeImpl(
db: AristoDbRef; # Database, top layer
rvid: RootedVertexID; # Root vertex
accPath: Hash256;
stoPath: NibblesBuf;
): Result[void,AristoError] =
## Implementation of *delete* sub-trie.
let (vtx, _) = db.getVtxRc(rvid).valueOr:
if error == GetVtxNotFound:
return ok()
return err(error)
case vtx.vType
of Branch:
for i in 0..15:
if vtx.bVid[i].isValid:
? db.delStoTreeImpl(
(rvid.root, vtx.bVid[i]), accPath,
stoPath & vtx.ePfx & NibblesBuf.nibble(byte i))
of Leaf:
let stoPath = Hash256(data: (stoPath & vtx.lPfx).getBytes())
db.layersPutStoLeaf(AccountKey.mixUp(accPath, stoPath), nil)
db.disposeOfVtx(rvid)
ok()
proc deleteImpl(
db: AristoDbRef; # Database, top layer
hike: Hike; # Fully expanded path
): Result[void,AristoError] =
## Implementation of *delete* functionality.
# Remove leaf entry
let lf = hike.legs[^1].wp
if lf.vtx.vType != Leaf:
return err(DelLeafExpexted)
db.disposeOfVtx((hike.root, lf.vid))
if 1 < hike.legs.len:
# Get current `Branch` vertex `br`
let br = block:
var wp = hike.legs[^2].wp
wp.vtx = wp.vtx.dup # make sure that layers are not impliciteley modified
wp
if br.vtx.vType != Branch:
return err(DelBranchExpexted)
# Unlink child vertex from structural table
br.vtx.bVid[hike.legs[^2].nibble] = VertexID(0)
db.layersPutVtx((hike.root, br.vid), br.vtx)
# Clear all Merkle hash keys up to the root key
for n in 0 .. hike.legs.len - 2:
let vid = hike.legs[n].wp.vid
db.layersResKey((hike.root, vid))
let nbl = block:
let rc = br.vtx.branchStillNeeded()
if rc.isErr:
return err(DelBranchWithoutRefs)
rc.value
if 0 <= nbl:
# Branch has only one entry - convert it to a leaf or join with parent
# Get child vertex (there must be one after a `Branch` node)
let
vid = br.vtx.bVid[nbl]
nxt = db.getVtx (hike.root, vid)
if not nxt.isValid:
return err(DelVidStaleVtx)
db.disposeOfVtx((hike.root, vid))
let vtx =
case nxt.vType
of Leaf:
VertexRef(
vType: Leaf,
lPfx: br.vtx.ePfx & NibblesBuf.nibble(nbl.byte) & nxt.lPfx,
lData: nxt.lData)
of Branch:
VertexRef(
vType: Branch,
ePfx: br.vtx.ePfx & NibblesBuf.nibble(nbl.byte) & nxt.ePfx,
bVid: nxt.bVid)
# Put the new vertex at the id of the obsolete branch
db.layersPutVtx((hike.root, br.vid), vtx)
ok()
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc deleteAccountRecord*(
db: AristoDbRef;
accPath: Hash256;
): Result[void,AristoError] =
## Delete the account leaf entry addressed by the argument `path`. If this
## leaf entry referres to a storage tree, this one will be deleted as well.
##
let
hike = accPath.hikeUp(VertexID(1), db).valueOr:
if error[1] in HikeAcceptableStopsNotFound:
return err(DelPathNotFound)
return err(error[1])
stoID = hike.legs[^1].wp.vtx.lData.stoID
# Delete storage tree if present
if stoID.isValid:
? db.delStoTreeImpl((stoID, stoID), accPath, NibblesBuf())
?db.deleteImpl(hike)
db.layersPutAccLeaf(accPath, nil)
ok()
proc deleteGenericData*(
db: AristoDbRef;
root: VertexID;
path: openArray[byte];
): Result[bool,AristoError] =
## Delete the leaf data entry addressed by the argument `path`. The MPT
## sub-tree the leaf data entry is subsumed under is passed as argument
## `root` which must be greater than `VertexID(1)` and smaller than
## `LEAST_FREE_VID`.
##
## The return value is `true` if the argument `path` deleted was the last
## one and the tree does not exist anymore.
##
# Verify that `root` is neither an accounts tree nor a strorage tree.
if not root.isValid:
return err(DelRootVidMissing)
elif root == VertexID(1):
return err(DelAccRootNotAccepted)
elif LEAST_FREE_VID <= root.distinctBase:
return err(DelStoRootNotAccepted)
let hike = path.hikeUp(root, db).valueOr:
if error[1] in HikeAcceptableStopsNotFound:
return err(DelPathNotFound)
return err(error[1])
?db.deleteImpl(hike)
ok(not db.getVtx((root, root)).isValid)
proc deleteGenericTree*(
db: AristoDbRef; # Database, top layer
root: VertexID; # Root vertex
): Result[void,AristoError] =
## Variant of `deleteGenericData()` for purging the whole MPT sub-tree.
##
# Verify that `root` is neither an accounts tree nor a strorage tree.
if not root.isValid:
return err(DelRootVidMissing)
elif root == VertexID(1):
return err(DelAccRootNotAccepted)
elif LEAST_FREE_VID <= root.distinctBase:
return err(DelStoRootNotAccepted)
db.delSubTreeImpl root
proc deleteStorageData*(
db: AristoDbRef;
accPath: Hash256; # Implies storage data tree
stoPath: Hash256;
): Result[bool,AristoError] =
## For a given account argument `accPath`, this function deletes the
## argument `stoPath` from the associated storage tree (if any, at all.) If
## the if the argument `stoPath` deleted was the last one on the storage tree,
## account leaf referred to by `accPath` will be updated so that it will
## not refer to a storage tree anymore. In the latter case only the function
## will return `true`.
##
let
accHike = db.fetchAccountHike(accPath).valueOr:
if error == FetchAccInaccessible:
return err(DelStoAccMissing)
return err(error)
wpAcc = accHike.legs[^1].wp
stoID = wpAcc.vtx.lData.stoID
if not stoID.isValid:
return err(DelStoRootMissing)
let stoHike = stoPath.hikeUp(stoID, db).valueOr:
if error[1] in HikeAcceptableStopsNotFound:
return err(DelPathNotFound)
return err(error[1])
# Mark account path Merkle keys for update
db.updateAccountForHasher accHike
?db.deleteImpl(stoHike)
db.layersPutStoLeaf(AccountKey.mixUp(accPath, stoPath), nil)
# Make sure that an account leaf has no dangling sub-trie
if db.getVtx((stoID, stoID)).isValid:
return ok(false)
# De-register the deleted storage tree from the account record
let leaf = wpAcc.vtx.dup # Dup on modify
leaf.lData.stoID = VertexID(0)
db.layersPutAccLeaf(accPath, leaf)
db.layersPutVtx((accHike.root, wpAcc.vid), leaf)
ok(true)
proc deleteStorageTree*(
db: AristoDbRef; # Database, top layer
accPath: Hash256; # Implies storage data tree
): Result[void,AristoError] =
## Variant of `deleteStorageData()` for purging the whole storage tree
## associated to the account argument `accPath`.
##
let
accHike = db.fetchAccountHike(accPath).valueOr:
if error == FetchAccInaccessible:
return err(DelStoAccMissing)
return err(error)
wpAcc = accHike.legs[^1].wp
stoID = wpAcc.vtx.lData.stoID
if not stoID.isValid:
return err(DelStoRootMissing)
# Mark account path Merkle keys for update
db.updateAccountForHasher accHike
? db.delStoTreeImpl((stoID, stoID), accPath, NibblesBuf())
# De-register the deleted storage tree from the accounts record
let leaf = wpAcc.vtx.dup # Dup on modify
leaf.lData.stoID = VertexID(0)
db.layersPutAccLeaf(accPath, leaf)
db.layersPutVtx((accHike.root, wpAcc.vid), leaf)
ok()
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------