From 456b1878928c75aae3f42e9f9c98a7ccd1a25666 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Wed, 28 Sep 2022 08:08:18 +0200
Subject: [PATCH] trie, eth/protocols/snap: less tiny db-writes during
 trie-healing (#25681)

This PR prevent making tiny writes during state healing, by only performing the batch-write if the accumulated data is large enough to be meaningful.
---
 eth/protocols/snap/sync.go | 34 ++++++++++++++++++----------------
 trie/sync.go               | 12 +++++++++++-
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/eth/protocols/snap/sync.go b/eth/protocols/snap/sync.go
index e236937897..f262824f9a 100644
--- a/eth/protocols/snap/sync.go
+++ b/eth/protocols/snap/sync.go
@@ -615,6 +615,8 @@ func (s *Syncer) Sync(root common.Hash, cancel chan struct{}) error {
 		}
 	}()
 	defer s.report(true)
+	// commit any trie- and bytecode-healing data.
+	defer s.commitHealer(true)
 
 	// Whether sync completed or not, disregard any future packets
 	defer func() {
@@ -2154,14 +2156,7 @@ func (s *Syncer) processTrienodeHealResponse(res *trienodeHealResponse) {
 			log.Error("Invalid trienode processed", "hash", hash, "err", err)
 		}
 	}
-	batch := s.db.NewBatch()
-	if err := s.healer.scheduler.Commit(batch); err != nil {
-		log.Error("Failed to commit healing data", "err", err)
-	}
-	if err := batch.Write(); err != nil {
-		log.Crit("Failed to persist healing data", "err", err)
-	}
-	log.Debug("Persisted set of healing data", "type", "trienodes", "bytes", common.StorageSize(batch.ValueSize()))
+	s.commitHealer(false)
 
 	// Calculate the processing rate of one filled trie node
 	rate := float64(fills) / (float64(time.Since(start)) / float64(time.Second))
@@ -2208,6 +2203,20 @@ func (s *Syncer) processTrienodeHealResponse(res *trienodeHealResponse) {
 	}
 }
 
+func (s *Syncer) commitHealer(force bool) {
+	if !force && s.healer.scheduler.MemSize() < ethdb.IdealBatchSize {
+		return
+	}
+	batch := s.db.NewBatch()
+	if err := s.healer.scheduler.Commit(batch); err != nil {
+		log.Error("Failed to commit healing data", "err", err)
+	}
+	if err := batch.Write(); err != nil {
+		log.Crit("Failed to persist healing data", "err", err)
+	}
+	log.Debug("Persisted set of healing data", "type", "trienodes", "bytes", common.StorageSize(batch.ValueSize()))
+}
+
 // processBytecodeHealResponse integrates an already validated bytecode response
 // into the healer tasks.
 func (s *Syncer) processBytecodeHealResponse(res *bytecodeHealResponse) {
@@ -2234,14 +2243,7 @@ func (s *Syncer) processBytecodeHealResponse(res *bytecodeHealResponse) {
 			log.Error("Invalid bytecode processed", "hash", hash, "err", err)
 		}
 	}
-	batch := s.db.NewBatch()
-	if err := s.healer.scheduler.Commit(batch); err != nil {
-		log.Error("Failed to commit healing data", "err", err)
-	}
-	if err := batch.Write(); err != nil {
-		log.Crit("Failed to persist healing data", "err", err)
-	}
-	log.Debug("Persisted set of healing data", "type", "bytecode", "bytes", common.StorageSize(batch.ValueSize()))
+	s.commitHealer(false)
 }
 
 // forwardAccountTask takes a filled account task and persists anything available
diff --git a/trie/sync.go b/trie/sync.go
index 862ce7e16e..31d3cbe91b 100644
--- a/trie/sync.go
+++ b/trie/sync.go
@@ -111,6 +111,7 @@ type syncMemBatch struct {
 	nodes  map[string][]byte      // In-memory membatch of recently completed nodes
 	hashes map[string]common.Hash // Hashes of recently completed nodes
 	codes  map[common.Hash][]byte // In-memory membatch of recently completed codes
+	size   uint64                 // Estimated batch-size of in-memory data.
 }
 
 // newSyncMemBatch allocates a new memory-buffer for not-yet persisted trie nodes.
@@ -338,6 +339,11 @@ func (s *Sync) Commit(dbw ethdb.Batch) error {
 	return nil
 }
 
+// MemSize returns an estimated size (in bytes) of the data held in the membatch.
+func (s *Sync) MemSize() uint64 {
+	return s.membatch.size
+}
+
 // Pending returns the number of state entries currently pending for download.
 func (s *Sync) Pending() int {
 	return len(s.nodeReqs) + len(s.codeReqs)
@@ -479,7 +485,10 @@ func (s *Sync) commitNodeRequest(req *nodeRequest) error {
 	// Write the node content to the membatch
 	s.membatch.nodes[string(req.path)] = req.data
 	s.membatch.hashes[string(req.path)] = req.hash
-
+	// The size tracking refers to the db-batch, not the in-memory data.
+	// Therefore, we ignore the req.path, and account only for the hash+data
+	// which eventually is written to db.
+	s.membatch.size += common.HashLength + uint64(len(req.data))
 	delete(s.nodeReqs, string(req.path))
 	s.fetches[len(req.path)]--
 
@@ -501,6 +510,7 @@ func (s *Sync) commitNodeRequest(req *nodeRequest) error {
 func (s *Sync) commitCodeRequest(req *codeRequest) error {
 	// Write the node content to the membatch
 	s.membatch.codes[req.hash] = req.data
+	s.membatch.size += common.HashLength + uint64(len(req.data))
 	delete(s.codeReqs, req.hash)
 	s.fetches[len(req.path)]--