Fix pivot setup after switch to full sync (#1562)

* Cosmetics, update logging, docu

* Fix pivot hand-over after switch to full sync

why:
  Got garbled after code clean up

nimbus/sync/misc/ticker.nim

@@ -155,13 +155,13 @@ proc snapTicker(t: TickerRef) {.gcsafe.} =
               &"({(data.nContracts[1]+0.5).int64})")
 
     if t.snap.recovery:
-      info "Snap sync statistics (recovery)",
+      info "Snap sync ticker (recovery)",
         up, nInst, bc, pv, nAcc, accCov, nSto, nStoQ, nCon, nConQ, mem
     elif recoveryDone:
-      info "Snap sync statistics (recovery done)",
+      info "Snap sync ticker (recovery done)",
         up, nInst, bc, pv, nAcc, accCov, nSto, nStoQ, nCon, nConQ, mem
     else:
-      info "Snap sync statistics",
+      info "Snap sync ticker",
         up, nInst, bc, pv, nAcc, accCov, nSto, nStoQ, nCon, nConQ, mem
 
 
@@ -190,10 +190,10 @@ proc fullTicker(t: TickerRef) {.gcsafe.} =
     t.visited = now
 
     if data.suspended:
-      info "Full sync statistics (suspended)", up, nInst, pv,
+      info "Full sync ticker (suspended)", up, nInst, pv,
         persistent, unprocessed, staged, queued, reOrg, mem
     else:
-      info "Full sync statistics", up, nInst, pv,
+      info "Full sync ticker", up, nInst, pv,
         persistent, unprocessed, staged, queued, reOrg, mem
 
 # ------------------------------------------------------------------------------

nimbus/sync/snap/worker/pass/pass_full.nim

@@ -129,10 +129,7 @@ proc processStaged(buddy: SnapBuddyRef): bool =
 # ------------------------------------------------------------------------------
 
 proc fullSyncSetup(ctx: SnapCtxRef) =
-  let blockNum = if ctx.pool.fullHeader.isNone: 0.toBlockNumber
+  ctx.pool.bCtx = BlockQueueCtxRef.init()
-                 else: ctx.pool.fullHeader.unsafeGet.blockNumber
-
-  ctx.pool.bCtx = BlockQueueCtxRef.init(blockNum + 1)
   ctx.pool.bPivot = BestPivotCtxRef.init(rng=ctx.pool.rng, minPeers=0)
   ctx.pool.ticker.init(cb = ctx.tickerUpdater())
 
@@ -173,38 +170,43 @@ proc fullSyncDaemon(ctx: SnapCtxRef) {.async.} =
 proc fullSyncPool(buddy: SnapBuddyRef, last: bool; laps: int): bool =
   let ctx = buddy.ctx
 
-  # Take over soft restart after switch to full sync mode.
+  # There is a soft re-setup after switch over to full sync mode if a pivot
-  # This process needs to be applied to all buddy peers.
+  # block header is available initialised from outside, i.e. snap sync swich.
   if ctx.pool.fullHeader.isSome:
-    # Soft start all peers on the second lap.
+    let stateHeader = ctx.pool.fullHeader.unsafeGet
-    ignoreException("fullSyncPool"):
+
-      if not buddy.fullSyncStart():
+    # Reinialise block queue descriptor relative to current pivot
-        # Start() method failed => wait for another peer
+    ctx.pool.startNumber = some(stateHeader.blockNumber)
-        buddy.ctrl.stopped = true
+    ctx.pool.bCtx = BlockQueueCtxRef.init(stateHeader.blockNumber + 1)
+
+    # Kick off ticker (was stopped by snap `release()` method)
+    ctx.pool.ticker.start()
+
+    # Store pivot as parent hash in database
+    ctx.pool.snapDb.kvDb.persistentBlockHeaderPut stateHeader
+
+    # Instead of genesis.
+    ctx.chain.com.startOfHistory = stateHeader.blockHash
+
+    when dumpDatabaseOnRollOver:         # <--- will go away (debugging only)
+      # Dump database ...                  <--- will go away (debugging only)
+      let nRecords =                     # <--- will go away (debugging only)
+        ctx.pool.snapDb.rockDb.dumpAllDb # <--- will go away (debugging only)
+      trace logTxt "dumped block chain database", nRecords
+
+    # Reset so that this action would not be triggered, again
+    ctx.pool.fullHeader = none(BlockHeader)
+
+  # Soft re-start buddy peers if on the second lap.
+  if 0 < laps and ctx.pool.startNumber.isSome:
+    if not buddy.fullSyncStart():
+      # Start() method failed => wait for another peer
+      buddy.ctrl.stopped = true
     if last:
-      let stateHeader = ctx.pool.fullHeader.unsafeGet
       trace logTxt "soft restart done", peer=buddy.peer, last, laps,
-        pivot=stateHeader.blockNumber.toStr,
+        pivot=ctx.pool.startNumber.toStr,
         mode=ctx.pool.syncMode.active, state= buddy.ctrl.state
-
+    return false # does stop magically when looping over peers is exhausted
-      # Kick off ticker (was stopped by snap `release()` method)
-      ctx.pool.ticker.start()
-
-      # Store pivot as parent hash in database
-      ctx.pool.snapDb.kvDb.persistentBlockHeaderPut stateHeader
-
-      # Instead of genesis.
-      ctx.chain.com.startOfHistory = stateHeader.blockHash
-
-      when dumpDatabaseOnRollOver:         # <--- will go away (debugging only)
-        # Dump database ...                  <--- will go away (debugging only)
-        let nRecords =                     # <--- will go away (debugging only)
-          ctx.pool.snapDb.rockDb.dumpAllDb # <--- will go away (debugging only)
-        trace logTxt "dumped block chain database", nRecords
-
-      # Reset so that this action would not be triggered, again
-      ctx.pool.fullHeader = none(BlockHeader)
-    return false # do stop magically when looping over peers is exhausted
 
   # Mind the gap, fill in if necessary (function is peer independent)
   buddy.only.bQueue.blockQueueGrout()

nimbus/sync/snap/worker_desc.nim

@@ -136,7 +136,8 @@ type
     recovery*: SnapRecoveryRef         ## Current recovery checkpoint/context
 
     # Full sync continuation parameters
-    fullHeader*: Option[BlockHeader]   ## Start full sync from here
+    fullHeader*: Option[BlockHeader]   ## Pivot hand over
+    startNumber*: Option[BlockNumber]  ## Start full sync from here
     bPivot*: BestPivotCtxRef           ## Global pivot descriptor
     bCtx*: BlockQueueCtxRef            ## Global block queue descriptor
 

nimbus/sync/sync_sched.nim

@@ -49,7 +49,7 @@
 ##   the loop starts. Re-setting it again results in repeating the loop. The
 ##   argument `laps` (starting with `0`) indicated the currend lap of the
 ##   repeated loops. To avoid continous looping, the number of `laps` is
-##   limited (see `exexPoolModeMax`, below.)
+##   limited (see `execPoolModeMax`, below.)
 ##
 ##   The argument `last` is set `true` if the last entry of the current loop
 ##   has been reached.