nimbus-eth1/nimbus/db/aristo/aristo_vid.nim
Jordan Hrycaj f926222fec
Aristo cull journal related stuff (#2288)
* Remove all journal related stuff

* Refactor function names journal*() => delta*(), filter*() => delta*()

* remove `trg` fileld from `FilterRef`

why:
  Same as `kMap[$1]`

* Re-type FilterRef.src as `HashKey`

why:
  So it is directly comparable to `kMap[$1]`

* Moved `vGen[]` field from `LayerFinalRef` to `LayerDeltaRef`

why:
  Then a separate `FilterRef` type is not needed, anymore

* Rename `roFilter` field in `AristoDbRef` => `balancer`

why:
  New name more appropriate.

* Replace `FilterRef` by `LayerDeltaRef` type

why:
  This allows to avoid copying into the `balancer` (see next patch set)
  most of the time. Typically, only one instance is running on the backend
  and the `balancer` is only used as a stage before saving data.

* Refactor way how to store data persistently

why:
  Avoid useless copy when staging `top` layer for persistently saving to
  backend.

* Fix copyright header?
2024-06-03 20:10:35 +00:00

113 lines
3.9 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.
## Handle vertex IDs on the layered Aristo DB delta architecture
## =============================================================
{.push raises: [].}
import
std/[algorithm, sequtils, typetraits],
"."/[aristo_desc, aristo_layers]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc vidFetch*(db: AristoDbRef; pristine = false): VertexID =
## Recycle or create a new `VertexID`. Reusable vertex *ID*s are kept in a
## list where the top entry *ID* has the property that any other *ID* larger
## is also not used on the database.
##
## The function prefers to return recycled vertex *ID*s if there are any.
## When the argument `pristine` is set `true`, the function guarantees to
## return a non-recycled, brand new vertex *ID* which is the preferred mode
## when creating leaf vertices.
##
if db.vGen.len == 0:
# Note that `VertexID(1)` is the root of the main trie
db.top.delta.vGen = @[VertexID(LEAST_FREE_VID+1)]
result = VertexID(LEAST_FREE_VID)
elif db.vGen.len == 1 or pristine:
result = db.vGen[^1]
db.top.delta.vGen[^1] = result + 1
else:
result = db.vGen[^2]
db.top.delta.vGen[^2] = db.top.delta.vGen[^1]
db.top.delta.vGen.setLen(db.vGen.len-1)
doAssert LEAST_FREE_VID <= result.distinctBase
proc vidPeek*(db: AristoDbRef): VertexID =
## Like `new()` without consuming this *ID*. It will return the *ID* that
## would be returned by the `new()` function.
##
case db.vGen.len:
of 0:
VertexID(LEAST_FREE_VID)
of 1:
db.vGen[^1]
else:
db.vGen[^2]
proc vidDispose*(db: AristoDbRef; vid: VertexID) =
## Recycle the argument `vtxID` which is useful after deleting entries from
## the vertex table to prevent the `VertexID` type key values small.
##
if LEAST_FREE_VID <= vid.distinctBase:
if db.vGen.len == 0:
db.top.delta.vGen = @[vid]
else:
let topID = db.vGen[^1]
# Only store smaller numbers: all numberts larger than `topID`
# are free numbers
if vid < topID:
db.top.delta.vGen[^1] = vid
db.top.delta.vGen.add topID
proc vidReorg*(vGen: seq[VertexID]): seq[VertexID] =
## Return a compacted version of the argument vertex ID generator state
## `vGen`. The function removes redundant items from the recycle queue and
## orders it in a way so that smaller `VertexID` numbers are re-used first.
##
# Apply heuristic test to avoid unnecessary sorting
var reOrgOk = false
if 2 < vGen.len and vGen[0] < vGen[^2]:
if vGen.len < 10:
reOrgOk = true
elif vGen[0] < vGen[1] and vGen[^3] < vGen[^2]:
reOrgOk = true
if reOrgOk:
let lst = vGen.mapIt(uint64(it)).sorted(Descending).mapIt(VertexID(it))
for n in 0 .. lst.len-2:
if lst[n].uint64 != lst[n+1].uint64 + 1:
# All elements of the sequence `lst[0]`..`lst[n]` are in decreasing
# order with distance 1. Only the smallest item is needed and the
# rest can be removed (as long as distance is 1.)
#
# Example:
# 7, 6, 5, 3.. => 5, 3.. => @[3..] & @[5]
# ^
# |
# n
#
return lst[n+1 .. lst.len-1] & @[lst[n]]
# Entries decrease continuously
return @[lst[^1]]
vGen
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------