nimbus-eth1/fluffy/database/content_db.nim

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# Fluffy
# Copyright (c) 2021-2024 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
{.push raises: [].}
import
chronicles,
metrics,
stint,
stew/results,
eth/db/kvstore,
eth/db/kvstore_sqlite3,
../network/state/state_content,
../network/wire/[portal_protocol, portal_protocol_config],
./content_db_custom_sql_functions
export kvstore_sqlite3
# This version of content db is the most basic, simple solution where data is
# stored no matter what content type or content network in the same kvstore with
# the content id as key. The content id is derived from the content key, and the
# deriviation is different depending on the content type. As we use content id,
# this part is currently out of the scope / API of the ContentDB.
# In the future it is likely that that either:
# 1. More kvstores are added per network, and thus depending on the network a
# different kvstore needs to be selected.
# 2. Or more kvstores are added per network and per content type, and thus
# content key fields are required to access the data.
# 3. Or databases are created per network (and kvstores pre content type) and
# thus depending on the network the right db needs to be selected.
declareCounter portal_pruning_counter,
"Number of pruning events which occured during the node's uptime",
labels = ["protocol_id"]
declareGauge portal_pruning_deleted_elements,
"Number of elements deleted in the last pruning", labels = ["protocol_id"]
const
contentDeletionFraction = 0.05 ## 5% of the content will be deleted when the
## storage capacity is hit and radius gets adjusted.
type
RowInfo =
tuple[contentId: array[32, byte], payloadLength: int64, distance: array[32, byte]]
ContentDB* = ref object
backend: SqStoreRef
kv: KvStoreRef
manualCheckpoint: bool
storageCapacity*: uint64
sizeStmt: SqliteStmt[NoParams, int64]
unusedSizeStmt: SqliteStmt[NoParams, int64]
vacuumStmt: SqliteStmt[NoParams, void]
contentCountStmt: SqliteStmt[NoParams, int64]
contentSizeStmt: SqliteStmt[NoParams, int64]
getAllOrderedByDistanceStmt: SqliteStmt[array[32, byte], RowInfo]
deleteOutOfRadiusStmt: SqliteStmt[(array[32, byte], array[32, byte]), void]
largestDistanceStmt: SqliteStmt[array[32, byte], array[32, byte]]
PutResultType* = enum
ContentStored
DbPruned
PutResult* = object
case kind*: PutResultType
of ContentStored:
discard
of DbPruned:
distanceOfFurthestElement*: UInt256
deletedFraction*: float64
deletedElements*: int64
template expectDb(x: auto): untyped =
# There's no meaningful error handling implemented for a corrupt database or
# full disk - this requires manual intervention, so we'll panic for now
x.expect("working database (disk broken/full?)")
proc new*(
T: type ContentDB,
path: string,
storageCapacity: uint64,
inMemory = false,
manualCheckpoint = false,
): ContentDB =
doAssert(storageCapacity <= uint64(int64.high))
let db =
if inMemory:
SqStoreRef.init("", "fluffy-test", inMemory = true).expect(
"working database (out of memory?)"
)
else:
SqStoreRef.init(path, "fluffy", manualCheckpoint = false).expectDb()
db.createCustomFunction("xorDistance", 2, xorDistance).expect(
"Custom function xorDistance creation OK"
)
db.createCustomFunction("isInRadius", 3, isInRadius).expect(
"Custom function isInRadius creation OK"
)
let sizeStmt = db.prepareStmt(
"SELECT page_count * page_size as size FROM pragma_page_count(), pragma_page_size();",
NoParams, int64,
)[]
let unusedSizeStmt = db.prepareStmt(
"SELECT freelist_count * page_size as size FROM pragma_freelist_count(), pragma_page_size();",
NoParams, int64,
)[]
let vacuumStmt = db.prepareStmt("VACUUM;", NoParams, void)[]
let kvStore = kvStore db.openKvStore().expectDb()
let contentSizeStmt =
db.prepareStmt("SELECT SUM(length(value)) FROM kvstore", NoParams, int64)[]
let contentCountStmt =
db.prepareStmt("SELECT COUNT(key) FROM kvstore;", NoParams, int64)[]
let getAllOrderedByDistanceStmt = db.prepareStmt(
"SELECT key, length(value), xorDistance(?, key) as distance FROM kvstore ORDER BY distance DESC",
array[32, byte],
RowInfo,
)[]
let deleteOutOfRadiusStmt = db.prepareStmt(
"DELETE FROM kvstore WHERE isInRadius(?, key, ?) == 0",
(array[32, byte], array[32, byte]),
void,
)[]
let largestDistanceStmt = db.prepareStmt(
"SELECT max(xorDistance(?, key)) FROM kvstore", array[32, byte], array[32, byte]
)[]
ContentDB(
kv: kvStore,
backend: db,
manualCheckpoint: manualCheckpoint,
storageCapacity: storageCapacity,
sizeStmt: sizeStmt,
unusedSizeStmt: unusedSizeStmt,
vacuumStmt: vacuumStmt,
contentSizeStmt: contentSizeStmt,
contentCountStmt: contentCountStmt,
getAllOrderedByDistanceStmt: getAllOrderedByDistanceStmt,
deleteOutOfRadiusStmt: deleteOutOfRadiusStmt,
largestDistanceStmt: largestDistanceStmt,
)
template disposeSafe(s: untyped): untyped =
if distinctBase(s) != nil:
s.dispose()
s = typeof(s)(nil)
proc close*(db: ContentDB) =
db.sizeStmt.disposeSafe()
db.unusedSizeStmt.disposeSafe()
db.vacuumStmt.disposeSafe()
db.contentCountStmt.disposeSafe()
db.contentSizeStmt.disposeSafe()
db.getAllOrderedByDistanceStmt.disposeSafe()
db.deleteOutOfRadiusStmt.disposeSafe()
db.largestDistanceStmt.disposeSafe()
discard db.kv.close()
## Private KvStoreRef Calls
proc get(kv: KvStoreRef, key: openArray[byte]): Opt[seq[byte]] =
var res: Opt[seq[byte]]
proc onData(data: openArray[byte]) =
res = Opt.some(@data)
discard kv.get(key, onData).expectDb()
return res
proc getSszDecoded(kv: KvStoreRef, key: openArray[byte], T: type auto): Opt[T] =
let res = kv.get(key)
if res.isSome():
try:
Opt.some(SSZ.decode(res.get(), T))
except SerializationError:
raiseAssert("Stored data should always be serialized correctly")
else:
Opt.none(T)
## Private ContentDB calls
proc get(db: ContentDB, key: openArray[byte]): Opt[seq[byte]] =
db.kv.get(key)
proc put(db: ContentDB, key, value: openArray[byte]) =
db.kv.put(key, value).expectDb()
proc contains(db: ContentDB, key: openArray[byte]): bool =
db.kv.contains(key).expectDb()
proc del(db: ContentDB, key: openArray[byte]) =
# TODO: Do we want to return the bool here too?
discard db.kv.del(key).expectDb()
proc getSszDecoded(db: ContentDB, key: openArray[byte], T: type auto): Opt[T] =
db.kv.getSszDecoded(key, T)
## Public ContentId based ContentDB calls
# TODO: Could also decide to use the ContentKey SSZ bytestring, as this is what
# gets send over the network in requests, but that would be a bigger key. Or the
# same hashing could be done on it here.
# However ContentId itself is already derived through different digests
# depending on the content type, and this ContentId typically needs to be
# checked with the Radius/distance of the node anyhow. So lets see how we end up
# using this mostly in the code.
proc get*(db: ContentDB, key: ContentId): Opt[seq[byte]] =
# TODO: Here it is unfortunate that ContentId is a uint256 instead of Digest256.
db.get(key.toBytesBE())
proc put*(db: ContentDB, key: ContentId, value: openArray[byte]) =
db.put(key.toBytesBE(), value)
proc contains*(db: ContentDB, key: ContentId): bool =
db.contains(key.toBytesBE())
proc del*(db: ContentDB, key: ContentId) =
db.del(key.toBytesBE())
proc getSszDecoded*(db: ContentDB, key: ContentId, T: type auto): Opt[T] =
db.getSszDecoded(key.toBytesBE(), T)
## Public calls to get database size, content size and similar.
proc size*(db: ContentDB): int64 =
## Return current size of DB as product of sqlite page_count and page_size:
## https://www.sqlite.org/pragma.html#pragma_page_count
## https://www.sqlite.org/pragma.html#pragma_page_size
## It returns the total size of db on the disk, i.e both data and metadata
## used to store content.
## It is worth noting that when deleting content, the size may lag behind due
## to the way how deleting works in sqlite.
## Good description can be found in: https://www.sqlite.org/lang_vacuum.html
var size: int64 = 0
discard (
db.sizeStmt.exec do(res: int64):
size = res
).expectDb()
return size
proc unusedSize(db: ContentDB): int64 =
## Returns the total size of the pages which are unused by the database,
## i.e they can be re-used for new content.
var size: int64 = 0
discard (
db.unusedSizeStmt.exec do(res: int64):
size = res
).expectDb()
return size
proc usedSize*(db: ContentDB): int64 =
## Returns the total size of the database (data + metadata) minus the unused
## pages.
db.size() - db.unusedSize()
proc contentSize*(db: ContentDB): int64 =
## Returns total size of the content stored in DB.
var size: int64 = 0
discard (
db.contentSizeStmt.exec do(res: int64):
size = res
).expectDb()
return size
proc contentCount*(db: ContentDB): int64 =
var count: int64 = 0
discard (
db.contentCountStmt.exec do(res: int64):
count = res
).expectDb()
return count
## Pruning related calls
proc getLargestDistance*(db: ContentDB, localId: UInt256): UInt256 =
var distanceBytes: array[32, byte]
discard (
db.largestDistanceStmt.exec(
localId.toBytesBE(),
proc(res: array[32, byte]) =
distanceBytes = res
,
)
).expectDb()
return UInt256.fromBytesBE(distanceBytes)
func estimateNewRadius(
currentSize: uint64, storageCapacity: uint64, currentRadius: UInt256
): UInt256 =
let sizeRatio = currentSize div storageCapacity
if sizeRatio > 0:
currentRadius div sizeRatio.stuint(256)
else:
currentRadius
func estimateNewRadius*(db: ContentDB, currentRadius: UInt256): UInt256 =
estimateNewRadius(uint64(db.usedSize()), db.storageCapacity, currentRadius)
proc deleteContentFraction*(
db: ContentDB, target: UInt256, fraction: float64
): (UInt256, int64, int64, int64) =
## Deletes at most `fraction` percent of content from the database.
## The content furthest from the provided `target` is deleted first.
# TODO: The usage of `db.contentSize()` for the deletion calculation versus
# `db.usedSize()` for the pruning threshold leads sometimes to some unexpected
# results of how much content gets up deleted.
doAssert(fraction > 0 and fraction < 1, "Deleted fraction should be > 0 and < 1")
let totalContentSize = db.contentSize()
let bytesToDelete = int64(fraction * float64(totalContentSize))
var deletedElements: int64 = 0
var ri: RowInfo
var deletedBytes: int64 = 0
let targetBytes = target.toBytesBE()
for e in db.getAllOrderedByDistanceStmt.exec(targetBytes, ri):
if deletedBytes + ri.payloadLength <= bytesToDelete:
db.del(ri.contentId)
deletedBytes = deletedBytes + ri.payloadLength
inc deletedElements
else:
return (
UInt256.fromBytesBE(ri.distance),
deletedBytes,
totalContentSize,
deletedElements,
)
proc reclaimSpace*(db: ContentDB): void =
## Runs sqlite VACUUM commands which rebuilds the db, repacking it into a
## minimal amount of disk space.
## Ideal mode of operation is to run it after several deletes.
## Another option would be to run 'PRAGMA auto_vacuum = FULL;' statement at
## the start of db to leave it up to sqlite to clean up.
db.vacuumStmt.exec().expectDb()
proc deleteContentOutOfRadius*(db: ContentDB, localId: UInt256, radius: UInt256) =
## Deletes all content that falls outside of the given radius range.
db.deleteOutOfRadiusStmt.exec((localId.toBytesBE(), radius.toBytesBE())).expect(
"SQL query OK"
)
proc reclaimAndTruncate*(db: ContentDB) =
notice "Reclaiming unused pages"
db.reclaimSpace()
if db.manualCheckpoint:
notice "Truncating WAL file"
db.backend.checkpoint(SqStoreCheckpointKind.truncate)
proc forcePrune*(db: ContentDB, localId: UInt256, radius: UInt256) =
## Force prune the database to a statically set radius. This will also run
## the reclaimSpace (vacuum) to free unused pages. As side effect this will
## cause the pruned database size to double in size on disk (wal file will be
## approximately the same size as the db). A truncate checkpoint is done to
## clean that up. In order to be able do the truncate checkpoint, the db needs
## to be initialized in with `manualCheckpoint` on, else this step will be
## skipped.
notice "Starting the pruning of content"
db.deleteContentOutOfRadius(localId, radius)
db.reclaimAndTruncate()
notice "Finished database pruning"
proc put*(
db: ContentDB, key: ContentId, value: openArray[byte], target: UInt256
): PutResult =
db.put(key, value)
# The used size is used as pruning threshold. This means that the database
# size will reach the size specified in db.storageCapacity and will stay
# around that size throughout the node's lifetime, as after content deletion
# due to pruning, the free pages will be re-used.
#
# Note:
# The `forcePrune` call must be used when database storage capacity is lowered
# either when setting a lower `storageCapacity` or when lowering a configured
# static radius.
# When not using the `forcePrune` functionality, pruning to the required
# capacity will not be very effictive and free pages will not be returned.
let dbSize = db.usedSize()
if dbSize < int64(db.storageCapacity):
return PutResult(kind: ContentStored)
else:
# Note:
# An approach of a deleting a full fraction is chosen here, in an attempt
# to not continiously require radius updates, which could have a negative
# impact on the network. However this should be further investigated, as
# doing a large fraction deletion could cause a temporary node performance
# degradation. The `contentDeletionFraction` might need further tuning or
# one could opt for a much more granular approach using sql statement
# in the trend of:
# "SELECT key FROM kvstore ORDER BY xorDistance(?, key) DESC LIMIT 1"
# Potential adjusting the LIMIT for how many items require deletion.
let (distanceOfFurthestElement, deletedBytes, totalContentSize, deletedElements) =
db.deleteContentFraction(target, contentDeletionFraction)
let deletedFraction = float64(deletedBytes) / float64(totalContentSize)
info "Deleted content fraction", deletedBytes, deletedElements, deletedFraction
return PutResult(
kind: DbPruned,
distanceOfFurthestElement: distanceOfFurthestElement,
deletedFraction: deletedFraction,
deletedElements: deletedElements,
)
proc adjustRadius(
p: PortalProtocol, deletedFraction: float64, distanceOfFurthestElement: UInt256
) =
# Invert fraction as the UInt256 implementation does not support
# multiplication by float
let invertedFractionAsInt = int64(1.0 / deletedFraction)
let scaledRadius = p.dataRadius div u256(invertedFractionAsInt)
# Choose a larger value to avoid the situation where the
# `distanceOfFurthestElement is very close to the local id so that the local
# radius would end up too small to accept any more data to the database.
# If scaledRadius radius will be larger it will still contain all elements.
let newRadius = max(scaledRadius, distanceOfFurthestElement)
info "Database radius adjusted",
oldRadius = p.dataRadius, newRadius = newRadius, distanceOfFurthestElement
# Both scaledRadius and distanceOfFurthestElement are smaller than current
# dataRadius, so the radius will constantly decrease through the node its
# lifetime.
p.dataRadius = newRadius
proc createGetHandler*(db: ContentDB): DbGetHandler =
return (
proc(contentKey: ByteList, contentId: ContentId): Opt[seq[byte]] =
let content = db.get(contentId).valueOr:
return Opt.none(seq[byte])
ok(content)
)
proc createStoreHandler*(
db: ContentDB, cfg: RadiusConfig, p: PortalProtocol
): DbStoreHandler =
return (
proc(
contentKey: ByteList, contentId: ContentId, content: seq[byte]
) {.raises: [], gcsafe.} =
# always re-check that the key is in the node range to make sure only
# content in range is stored.
# TODO: current silent assumption is that both ContentDB and PortalProtocol
# are using the same xor distance function
if p.inRange(contentId):
case cfg.kind
of Dynamic:
# In case of dynamic radius setting we obey storage limits and adjust
# radius to store network fraction corresponding to those storage limits.
let res = db.put(contentId, content, p.localNode.id)
if res.kind == DbPruned:
portal_pruning_counter.inc(labelValues = [$p.protocolId])
portal_pruning_deleted_elements.set(
res.deletedElements.int64, labelValues = [$p.protocolId]
)
if res.deletedFraction > 0.0:
p.adjustRadius(res.deletedFraction, res.distanceOfFurthestElement)
else:
# Note:
# This can occur when the furthest content is bigger than the fraction
# size. This is unlikely to happen as it would require either very
# small storage capacity or a very small `contentDeletionFraction`
# combined with some big content.
info "Database pruning attempt resulted in no content deleted"
return
of Static:
# If the config is set statically, radius is not adjusted, and is kept
# constant thorugh node life time, also database max size is disabled
# so we will effectivly store fraction of the network
db.put(contentId, content)
)