Jordan Hrycaj 5ac362fe6f
Aristo and kvt balancer management update (#2504)
* Aristo: Merge `delta_siblings` module into `deltaPersistent()`

* Aristo: Add `isEmpty()` for canonical checking whether a layer is empty

* Aristo: Merge `LayerDeltaRef` into `LayerObj`

why:
  No need to maintain nested object refs anymore. Previously the
 `LayerDeltaRef` object had a companion `LayerFinalRef` which held
  non-delta layer information.

* Kvt: Merge `LayerDeltaRef` into `LayerRef`

why:
  No need to maintain nested object refs (as with `Aristo`)

* Kvt: Re-write balancer logic similar to `Aristo`

why:
  Although `Kvt` was a cheap copy of `Aristo` it sort of got out of
  sync and the balancer code was wrong.

* Update iterator over forked peers

why:
  Yield additional field `isLast` indicating that the last iteration
  cycle was approached.

* Optimise balancer calculation.

why:
  One can often avoid providing a new object containing the merge of two
  layers for the balancer. This avoids copying tables. In some cases this
  is replaced by `hasKey()` look ups though. One uses one of the two
  to combine and merges the other into the first.

  Of course, this needs some checks for making sure that none of the
  components to merge is eventually shared with something else.

* Fix copyright year
2024-07-18 21:32:32 +00:00

71 lines
2.3 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.
## Kvt DB -- Transaction stow/save helper
## ======================================
##
{.push raises: [].}
import
std/tables,
results,
../kvt_delta/delta_merge,
".."/[kvt_desc, kvt_delta]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc txStowOk*(
db: KvtDbRef; # Database
persistent: bool; # Stage only unless `true`
): Result[void,KvtError] =
## Verify that `txStow()` can go ahead
if not db.txRef.isNil:
return err(TxPendingTx)
if 0 < db.stack.len:
return err(TxStackGarbled)
if persistent and not db.deltaPersistentOk():
return err(TxBackendNotWritable)
ok()
proc txStow*(
db: KvtDbRef; # Database
persistent: bool; # Stage only unless `true`
): Result[void,KvtError] =
## The function saves the data from the top layer cache into the
## backend database.
##
## If there is no backend the function returns immediately with an error.
## The same happens if there is a pending transaction.
##
? db.txStowOk persistent
if 0 < db.top.sTab.len:
# Note that `deltaMerge()` will return the `db.top` argument if the
# `db.balancer` is `nil`. Also, the `db.balancer` is read-only. In the
# case that there are no forked peers one can ignore that restriction as
# no balancer is shared.
db.balancer = deltaMerge(
db.top, modUpperOk = true, db.balancer, modLowerOk = db.nForked()==0)
# New empty top layer
db.top = LayerRef()
if persistent:
# Move `balancer` data into persistent tables
? db.deltaPersistent()
ok()
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------