Backfill only up to MIN_EPOCHS_FOR_BLOCK_REQUESTS blocks (#4421)

When backfilling, we only need to download blocks that are newer than
MIN_EPOCHS_FOR_BLOCK_REQUESTS - the rest cannot reliably be fetched from
the network and does not have to be provided to others.

This change affects only trusted-node-synced clients - genesis sync
continues to work as before (because it needs to construct a state by
building it from genesis).

Those wishing to complete a backfill should do so with era files
instead.

beacon_chain/consensus_object_pools/block_clearance.nim

@@ -410,6 +410,13 @@ proc addBackfillBlock*(
     debug "Block does not match expected backfill root"
     return err(VerifierError.MissingParent) # MissingChild really, but ..
 
+  if blck.slot < dag.horizon:
+    # This can happen as the horizon keeps moving - we'll discard it as
+    # duplicate since it would have duplicated an existing block had we been
+    # interested
+    debug "Block past horizon, dropping", horizon = dag.horizon
+    return err(VerifierError.Duplicate)
+
   checkSignature()
 
   let sigVerifyTick = Moment.now

beacon_chain/consensus_object_pools/block_pools_types.nim

@@ -362,6 +362,14 @@ template frontfill*(dagParam: ChainDAGRef): Opt[BlockId] =
   else:
     dag.genesis
 
+func horizon*(dag: ChainDAGRef): Slot =
+  ## The sync horizon that we target during backfill - ie we will not backfill
+  ## blocks older than this from the network
+  if dag.head.slot.epoch > dag.cfg.MIN_EPOCHS_FOR_BLOCK_REQUESTS:
+    start_slot(dag.head.slot.epoch - dag.cfg.MIN_EPOCHS_FOR_BLOCK_REQUESTS)
+  else:
+    GENESIS_SLOT
+
 template epoch*(e: EpochRef): Epoch = e.key.epoch
 
 func shortLog*(v: EpochKey): string =

beacon_chain/consensus_object_pools/blockchain_dag.nim

@@ -1295,8 +1295,13 @@ proc getBlockRange*(
     head = shortLog(dag.head.root), requestedCount, startSlot, skipStep, headSlot
 
   if startSlot < dag.backfill.slot:
-    notice "Got request for pre-backfill slot",
-      startSlot, backfillSlot = dag.backfill.slot
+    if startSlot < dag.horizon:
+      # We will not backfill these
+      debug "Got request for pre-horizon slot",
+        startSlot, backfillSlot = dag.backfill.slot
+    else:
+      notice "Got request for pre-backfill slot",
+        startSlot, backfillSlot = dag.backfill.slot
     return output.len
 
   if headSlot <= startSlot or requestedCount == 0:

beacon_chain/gossip_processing/block_processor.nim

@@ -244,7 +244,6 @@ proc newExecutionPayload*(
     executionPayload: bellatrix.ExecutionPayload | capella.ExecutionPayload):
     Future[Opt[PayloadExecutionStatus]] {.async.} =
   if eth1Monitor.isNil:
-    warn "newPayload: attempting to process execution payload without Eth1Monitor. Ensure --web3-url setting is correct and JWT is configured."
     return Opt.none PayloadExecutionStatus
 
   debug "newPayload: inserting block into execution engine",
@@ -320,6 +319,9 @@ proc getExecutionValidity(
   if not blck.message.is_execution_block:
     return NewPayloadStatus.valid  # vacuously
 
+  if eth1Monitor.isNil:
+    return NewPayloadStatus.noResponse
+
   try:
     # Minimize window for Eth1 monitor to shut down connection
     await eth1Monitor.ensureDataProvider()
@@ -381,8 +383,10 @@ proc storeBlock*(
       # `processBlock` (indirectly). `validator_duties` does call `storeBlock`
       # directly, so is exposed to this, but only cares about whether there is
       # an error or not.
-      return err((
-        VerifierError.MissingParent, ProcessingStatus.notCompleted))
+      if self[].consensusManager.eth1Monitor.isNil:
+        warn "Attempting to process execution payload without execution client. Ensure --web3-url setting is correct and JWT is configured."
+
+      return err((VerifierError.MissingParent, ProcessingStatus.notCompleted))
 
     # Client software MUST validate blockHash value as being equivalent to
     # Keccak256(RLP(ExecutionBlockHeader))

beacon_chain/nimbus_beacon_node.nim

@@ -277,10 +277,7 @@ proc initFullNode(
     dag.backfill.slot
 
   func getFrontfillSlot(): Slot =
-    if dag.frontfill.isSome():
-      dag.frontfill.get().slot
-    else:
-      GENESIS_SLOT
+    max(dag.frontfill.get(BlockId()).slot, dag.horizon)
 
   let
     quarantine = newClone(
@@ -451,10 +448,7 @@ proc init*(T: type BeaconNode,
   let optJwtSecret = rng[].loadJwtSecret(config, allowCreate = false)
 
   if config.web3Urls.len() == 0:
-    if cfg.BELLATRIX_FORK_EPOCH == FAR_FUTURE_EPOCH:
-      notice "Running without execution client - validator features partially disabled (see https://nimbus.guide/eth1.html)"
-    else:
-      notice "Running without execution client - validator features disabled (see https://nimbus.guide/eth1.html)"
+    notice "Running without execution client - validator features disabled (see https://nimbus.guide/eth1.html)"
 
   var eth1Monitor: Eth1Monitor
 
@@ -1633,8 +1627,6 @@ proc start*(node: BeaconNode) {.raises: [Defect, CatchableError].} =
 
   if node.eth1Monitor != nil:
     node.eth1Monitor.start()
-  else:
-    notice "Running without execution chain monitor, block producation partially disabled"
 
   node.run()
 

beacon_chain/sync/sync_manager.nim

@@ -183,10 +183,19 @@ proc getBlocks*[A, B](man: SyncManager[A, B], peer: A,
     return
 
 proc remainingSlots(man: SyncManager): uint64 =
+  let
+    first = man.getFirstSlot()
+    last = man.getLastSlot()
   if man.direction == SyncQueueKind.Forward:
-    man.getLastSlot() - man.getFirstSlot()
+    if last > first:
+      man.getLastSlot() - man.getFirstSlot()
+    else:
+      0'u64
   else:
-    man.getFirstSlot() - man.getLastSlot()
+    if first > last:
+      man.getFirstSlot() - man.getLastSlot()
+    else:
+      0'u64
 
 proc syncStep[A, B](man: SyncManager[A, B], index: int, peer: A) {.async.} =
   logScope:
@@ -297,9 +306,8 @@ proc syncStep[A, B](man: SyncManager[A, B], index: int, peer: A) {.async.} =
     peer.updateScore(PeerScoreUseless)
     return
 
-  if man.direction == SyncQueueKind.Forward:
-    # Wall clock keeps ticking, so we need to update the queue
-    man.queue.updateLastSlot(man.getLastSlot())
+  # Wall clock keeps ticking, so we need to update the queue
+  man.queue.updateLastSlot(man.getLastSlot())
 
   man.workers[index].status = SyncWorkerStatus.Requesting
   let req = man.queue.pop(peerSlot, peer)
@@ -575,15 +583,27 @@ proc syncLoop[A, B](man: SyncManager[A, B]) {.async.} =
       progress =
         case man.queue.kind
         of SyncQueueKind.Forward:
-          man.queue.outSlot - pivot
+          if man.queue.outSlot >= pivot:
+            man.queue.outSlot - pivot
+          else:
+            0'u64
         of SyncQueueKind.Backward:
-          pivot - man.queue.outSlot
+          if pivot >= man.queue.outSlot:
+            pivot - man.queue.outSlot
+          else:
+            0'u64
       total =
         case man.queue.kind
         of SyncQueueKind.Forward:
-          man.queue.finalSlot + 1'u64 - pivot
+          if man.queue.finalSlot >= pivot:
+            man.queue.finalSlot + 1'u64 - pivot
+          else:
+            0'u64
         of SyncQueueKind.Backward:
-          pivot + 1'u64 - man.queue.finalSlot
+          if pivot >= man.queue.finalSlot:
+            pivot + 1'u64 - man.queue.finalSlot
+          else:
+            0'u64
       remaining = total - progress
       done =
         if total > 0:

beacon_chain/sync/sync_queue.nim

@@ -281,17 +281,7 @@ proc makePending*[T](sq: SyncQueue[T], req: var SyncRequest[T]) =
 
 proc updateLastSlot*[T](sq: SyncQueue[T], last: Slot) {.inline.} =
   ## Update last slot stored in queue ``sq`` with value ``last``.
-  case sq.kind
-  of SyncQueueKind.Forward:
-    doAssert(sq.finalSlot <= last,
-             "Last slot could not be lower then stored one " &
-             $sq.finalSlot & " <= " & $last)
-    sq.finalSlot = last
-  of SyncQueueKind.Backward:
-    doAssert(sq.finalSlot >= last,
-             "Last slot could not be higher then stored one " &
-             $sq.finalSlot & " >= " & $last)
-    sq.finalSlot = last
+  sq.finalSlot = last
 
 proc wakeupWaiters[T](sq: SyncQueue[T], reset = false) =
   ## Wakeup one or all blocked waiters.
@@ -793,7 +783,7 @@ proc push*[T](sq: SyncQueue[T], sr: SyncRequest[T],
           if safeSlot > failSlot:
             let rewindSlot = sq.getRewindPoint(failSlot, safeSlot)
             # It's quite common peers give us fewer blocks than we ask for
-            info "Gap in block range response, rewinding", request = req,
+            debug "Gap in block range response, rewinding", request = req,
                  rewind_to_slot = rewindSlot, rewind_fail_slot = failSlot,
                  finalized_slot = safeSlot, blocks_count = len(item.data),
                  blocks_map = getShortMap(req, item.data)
@@ -974,22 +964,31 @@ proc len*[T](sq: SyncQueue[T]): uint64 {.inline.} =
   ## Returns number of slots left in queue ``sq``.
   case sq.kind
   of SyncQueueKind.Forward:
-    sq.finalSlot + 1'u64 - sq.outSlot
+    if sq.finalSlot >= sq.outSlot:
+      sq.finalSlot + 1'u64 - sq.outSlot
+    else:
+      0'u64
   of SyncQueueKind.Backward:
-    sq.outSlot + 1'u64 - sq.finalSlot
+    if sq.outSlot >= sq.finalSlot:
+      sq.outSlot + 1'u64 - sq.finalSlot
+    else:
+      0'u64
 
 proc total*[T](sq: SyncQueue[T]): uint64 {.inline.} =
   ## Returns total number of slots in queue ``sq``.
   case sq.kind
   of SyncQueueKind.Forward:
-    sq.finalSlot + 1'u64 - sq.startSlot
+    if sq.finalSlot >= sq.startSlot:
+      sq.finalSlot + 1'u64 - sq.startSlot
+    else:
+      0'u64
   of SyncQueueKind.Backward:
-    sq.startSlot + 1'u64 - sq.finalSlot
+    if sq.startSlot >= sq.finalSlot:
+      sq.startSlot + 1'u64 - sq.finalSlot
+    else:
+      0'u64
 
 proc progress*[T](sq: SyncQueue[T]): uint64 =
-  ## How many slots we've synced so far
-  case sq.kind
-  of SyncQueueKind.Forward:
-    sq.outSlot - sq.startSlot
-  of SyncQueueKind.Backward:
-    sq.startSlot - sq.outSlot
+  ## How many useful slots we've synced so far, adjusting for how much has
+  ## become obsolete by time movements
+  sq.total - sq.len

beacon_chain/trusted_node_sync.nim

@@ -209,18 +209,18 @@ proc doTrustedNodeSync*(
     validatorMonitor = newClone(ValidatorMonitor.init(false, false))
     dag = ChainDAGRef.init(cfg, db, validatorMonitor, {}, eraPath = eraDir)
     backfillSlot = dag.backfill.slot
-    frontfill = dag.frontfill.valueOr(BlockId())
+    horizon = max(dag.horizon, dag.frontfill.valueOr(BlockId()).slot)
 
-  let canReindex = if backfillSlot <= frontfill.slot:
-    info "Database backfilled"
+  let canReindex = if backfillSlot <= horizon:
+    info "Database backfilled", backfill = dag.backfill, horizon
     true
   elif backfill:
     # +1 because we need to download the frontfill slot for the frontfill match
     # detection to kick in, in addBackfillBlock
-    let missingSlots = dag.backfill.slot - frontfill.slot + 1
+    let missingSlots = dag.backfill.slot - horizon + 1
 
     notice "Downloading historical blocks - you can interrupt this process at any time and it automatically be completed when you start the beacon node",
-      backfillSlot, frontfill, missingSlots
+      backfillSlot, horizon, missingSlots
 
     var # Same averaging as SyncManager
       syncCount = 0
@@ -260,7 +260,7 @@ proc doTrustedNodeSync*(
         syncCount += 1
 
         let
-          remaining = dag.backfill.slot - frontfill.slot
+          remaining = dag.backfill.slot - horizon
           slotsPerSec = speed(stamp, newStamp)
         avgSyncSpeed = avgSyncSpeed + (slotsPerSec - avgSyncSpeed) / float(syncCount)
 
@@ -314,9 +314,9 @@ proc doTrustedNodeSync*(
       notice "Backfilling incomplete - blocks will be downloaded when starting the node", msg = exc.msg
       false
   else:
-    let missingSlots = dag.backfill.slot - frontfill.slot
+    let missingSlots = dag.backfill.slot - horizon
     notice "Database initialized, historical blocks will be backfilled when starting the node",
-      missingSlots
+      missingSlots, backfill = dag.backfill, horizon
 
     false