nimbus-eth1/nimbus/db/aristo/aristo_check.nim
Jacek Sieka 2961905a95
aristo: fork support via layers/txframes (#2960)
* aristo: fork support via layers/txframes

This change reorganises how the database is accessed: instead holding a
"current frame" in the database object, a dag of frames is created based
on the "base frame" held in `AristoDbRef` and all database access
happens through this frame, which can be thought of as a consistent
point-in-time snapshot of the database based on a particular fork of the
chain.

In the code, "frame", "transaction" and "layer" is used to denote more
or less the same thing: a dag of stacked changes backed by the on-disk
database.

Although this is not a requirement, in practice each frame holds the
change set of a single block - as such, the frame and its ancestors
leading up to the on-disk state represents the state of the database
after that block has been applied.

"committing" means merging the changes to its parent frame so that the
difference between them is lost and only the cumulative changes remain -
this facility enables frames to be combined arbitrarily wherever they
are in the dag.

In particular, it becomes possible to consolidate a set of changes near
the base of the dag and commit those to disk without having to re-do the
in-memory frames built on top of them - this is useful for "flattening"
a set of changes during a base update and sending those to storage
without having to perform a block replay on top.

Looking at abstractions, a side effect of this change is that the KVT
and Aristo are brought closer together by considering them to be part of
the "same" atomic transaction set - the way the code gets organised,
applying a block and saving it to the kvt happens in the same "logical"
frame - therefore, discarding the frame discards both the aristo and kvt
changes at the same time - likewise, they are persisted to disk together
- this makes reasoning about the database somewhat easier but has the
downside of increased memory usage, something that perhaps will need
addressing in the future.

Because the code reasons more strictly about frames and the state of the
persisted database, it also makes it more visible where ForkedChain
should be used and where it is still missing - in particular, frames
represent a single branch of history while forkedchain manages multiple
parallel forks - user-facing services such as the RPC should use the
latter, ie until it has been finalized, a getBlock request should
consider all forks and not just the blocks in the canonical head branch.

Another advantage of this approach is that `AristoDbRef` conceptually
becomes more simple - removing its tracking of the "current" transaction
stack simplifies reasoning about what can go wrong since this state now
has to be passed around in the form of `AristoTxRef` - as such, many of
the tests and facilities in the code that were dealing with "stack
inconsistency" are now structurally prevented from happening. The test
suite will need significant refactoring after this change.

Once this change has been merged, there are several follow-ups to do:

* there's no mechanism for keeping frames up to date as they get
committed or rolled back - TODO
* naming is confused - many names for the same thing for legacy reason
* forkedchain support is still missing in lots of code
* clean up redundant logic based on previous designs - in particular the
debug and introspection code no longer makes sense
* the way change sets are stored will probably need revisiting - because
it's a stack of changes where each frame must be interrogated to find an
on-disk value, with a base distance of 128 we'll at minimum have to
perform 128 frame lookups for *every* database interaction - regardless,
the "dag-like" nature will stay
* dispose and commit are poorly defined and perhaps redundant - in
theory, one could simply let the GC collect abandoned frames etc, though
it's likely an explicit mechanism will remain useful, so they stay for
now

More about the changes:

* `AristoDbRef` gains a `txRef` field (todo: rename) that "more or less"
corresponds to the old `balancer` field
* `AristoDbRef.stack` is gone - instead, there's a chain of
`AristoTxRef` objects that hold their respective "layer" which has the
actual changes
* No more reasoning about "top" and "stack" - instead, each
`AristoTxRef` can be a "head" that "more or less" corresponds to the old
single-history `top` notion and its stack
* `level` still represents "distance to base" - it's computed from the
parent chain instead of being stored
* one has to be careful not to use frames where forkedchain was intended
- layers are only for a single branch of history!

* fix layer vtop after rollback

* engine fix

* Fix test_txpool

* Fix test_rpc

* Fix copyright year

* fix simulator

* Fix copyright year

* Fix copyright year

* Fix tracer

* Fix infinite recursion bug

* Remove aristo and kvt empty files

* Fic copyright year

* Fix fc chain_kvt

* ForkedChain refactoring

* Fix merge master conflict

* Fix copyright year

* Reparent txFrame

* Fix test

* Fix txFrame reparent again

* Cleanup and fix test

* UpdateBase bugfix and fix test

* Fixe newPayload bug discovered by hive

* Fix engine api fcu

* Clean up call template, chain_kvt, andn txguid

* Fix copyright year

* work around base block loading issue

* Add test

* Fix updateHead bug

* Fix updateBase bug

* Change func commitBase to proc commitBase

* Touch up and fix debug mode crash

---------

Co-authored-by: jangko <jangko128@gmail.com>
2025-02-06 14:04:50 +07:00

115 lines
4.1 KiB
Nim

# nimbus-eth1
# Copyright (c) 2023-2025 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 -- Consistency checks
## ===============================
##
{.push raises: [].}
import
eth/common/hashes,
results,
./aristo_walk/persistent,
"."/[aristo_desc, aristo_get, aristo_init],
./aristo_check/[check_be, check_top, check_twig]
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
proc checkTop*(
db: AristoTxRef; # Database, top layer
proofMode = false; # Has proof nodes
): Result[void,(VertexID,AristoError)] =
## Verify that the cache structure is correct as it would be after `merge()`
## operations. Unless `proofMode` is set `true` it would not fully check
## against the backend, which is typically not applicable after `delete()`
## operations.
##
## The following is verified:
##
## * Each `sTab[]` entry has a valid vertex which can be compiled as a node.
## If `proofMode` is set `false`, the Merkle hashes are recompiled and must
## match.
##
if proofMode:
? db.checkTopProofMode()
else:
? db.checkTopStrict()
db.checkTopCommon()
proc checkBE*(
db: AristoDbRef; # Database, top layer
): Result[void,(VertexID,AristoError)] =
## Verify database backend structure. If the argument `relax` is set `false`,
## all necessary Merkle hashes are compiled and verified. If the argument
## `cache` is set `true`, the cache is also checked so that a safe operation
## (like `resolveBackendFilter()`) will leave the backend consistent.
##
## The following is verified:
##
## * Each vertex ID on the structural table can be represented as a Merkle
## patricia Tree node. If `relax` is set `false`, the Merkle hashes are
## all recompiled and must match.
##
## * The set of free vertex IDa as potentally suppliedby the ID generator
## state is disjunct to the set of already used vertex IDs on the database.
## Moreover, the union of both sets is equivalent to the set of positive
## `uint64` numbers.
##
case db.backend.kind:
of BackendMemory:
return MemBackendRef.checkBE db
of BackendRocksDB, BackendRdbHosting:
return RdbBackendRef.checkBE db
of BackendVoid:
return VoidBackendRef.checkBE db
proc check*(
db: AristoTxRef; # Database
relax = false; # Check existing hashes only
cache = true; # Also verify against top layer cache
proofMode = false; # Has proof nodes
): Result[void,(VertexID,AristoError)] =
## Shortcut for running `checkTop()` followed by `checkBE()`
? db.checkTop(proofMode = proofMode)
# ? db.checkBE()
ok()
proc check*(
db: AristoTxRef; # Database
accPath: Hash32; # Account key
): Result[void,AristoError] =
## Check accounts tree path `accPath` against portal proof generation and
## verification.
##
## Note that this check might have side effects in that it might compile
## the hash keys on the accounts sub-tree.
db.checkTwig(accPath)
proc check*(
db: AristoTxRef; # Database
accPath: Hash32; # Account key
stoPath: Hash32; # Storage key
): Result[void,AristoError] =
## Check account tree `Account key` against portal proof generation and
## verification.
##
## Note that this check might have side effects in that it might compile
## the hash keys on the particulat storage sub-tree.
db.checkTwig(accPath, stoPath)
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------