From 64ca976b762a1296f936f1c7886896488849a915 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Mon, 20 Sep 2021 23:00:58 +0200
Subject: [PATCH 1/2] core/rawdb: utilize AncientRange when initiating from
 freezer

---
 core/rawdb/chain_iterator.go | 51 ++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/core/rawdb/chain_iterator.go b/core/rawdb/chain_iterator.go
index ad222005be8d5..dbf5181be28a9 100644
--- a/core/rawdb/chain_iterator.go
+++ b/core/rawdb/chain_iterator.go
@@ -44,24 +44,29 @@ func InitDatabaseFromFreezer(db ethdb.Database) {
 		logged = start.Add(-7 * time.Second) // Unindex during import is fast, don't double log
 		hash   common.Hash
 	)
-	for i := uint64(0); i < frozen; i++ {
-		// Since the freezer has all data in sequential order on a file,
-		// it would be 'neat' to read more data in one go, and let the
-		// freezerdb return N items (e.g up to 1000 items per go)
-		// That would require an API change in Ancients though
-		if h, err := db.Ancient(freezerHashTable, i); err != nil {
+	for i := uint64(0); i < frozen; {
+		// We read 100K hashes at a time, for a total of 3.2M
+		count := uint64(100_000)
+		if i+count > frozen {
+			count = frozen - i
+		}
+		data, err := db.AncientRange(freezerHashTable, i, count, 32*count)
+		if err != nil {
 			log.Crit("Failed to init database from freezer", "err", err)
-		} else {
-			hash = common.BytesToHash(h)
 		}
-		WriteHeaderNumber(batch, hash, i)
-		// If enough data was accumulated in memory or we're at the last block, dump to disk
-		if batch.ValueSize() > ethdb.IdealBatchSize {
-			if err := batch.Write(); err != nil {
-				log.Crit("Failed to write data to db", "err", err)
+		for j, h := range data {
+			number := i + uint64(j)
+			hash = common.BytesToHash(h)
+			WriteHeaderNumber(batch, hash, number)
+			// If enough data was accumulated in memory or we're at the last block, dump to disk
+			if batch.ValueSize() > ethdb.IdealBatchSize {
+				if err := batch.Write(); err != nil {
+					log.Crit("Failed to write data to db", "err", err)
+				}
+				batch.Reset()
 			}
-			batch.Reset()
 		}
+		i += uint64(len(data))
 		// If we've spent too much time already, notify the user of what we're doing
 		if time.Since(logged) > 8*time.Second {
 			log.Info("Initializing database from freezer", "total", frozen, "number", i, "hash", hash, "elapsed", common.PrettyDuration(time.Since(start)))
@@ -76,6 +81,24 @@ func InitDatabaseFromFreezer(db ethdb.Database) {
 	WriteHeadHeaderHash(db, hash)
 	WriteHeadFastBlockHash(db, hash)
 	log.Info("Initialized database from freezer", "blocks", frozen, "elapsed", common.PrettyDuration(time.Since(start)))
+	/**
+	Sanity check
+	This code should be removed before merging this PR, but it
+	is useful for validating that things work as expected.
+	*/
+	for i := uint64(0); i < frozen; i++ {
+		h, err := db.Ancient(freezerHashTable, i)
+		if err != nil {
+			log.Crit("Something bad happened", "number", i, "err", err)
+		}
+		num := ReadHeaderNumber(db, common.BytesToHash(h))
+		if num == nil {
+			log.Crit("Missing hash->number mapping", "number", i, "err", err)
+		}
+		if *num != i {
+			log.Crit("Erroneous hash->number mapping", "number", i)
+		}
+	}
 }
 
 type blockTxHashes struct {

From f6769d01759ce1396bec55360ad575876f5debd6 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Mon, 25 Oct 2021 16:30:12 +0200
Subject: [PATCH 2/2] core/rawdb: remove debug sanity check

---
 core/rawdb/chain_iterator.go | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/core/rawdb/chain_iterator.go b/core/rawdb/chain_iterator.go
index dbf5181be28a9..daee721594e62 100644
--- a/core/rawdb/chain_iterator.go
+++ b/core/rawdb/chain_iterator.go
@@ -81,24 +81,6 @@ func InitDatabaseFromFreezer(db ethdb.Database) {
 	WriteHeadHeaderHash(db, hash)
 	WriteHeadFastBlockHash(db, hash)
 	log.Info("Initialized database from freezer", "blocks", frozen, "elapsed", common.PrettyDuration(time.Since(start)))
-	/**
-	Sanity check
-	This code should be removed before merging this PR, but it
-	is useful for validating that things work as expected.
-	*/
-	for i := uint64(0); i < frozen; i++ {
-		h, err := db.Ancient(freezerHashTable, i)
-		if err != nil {
-			log.Crit("Something bad happened", "number", i, "err", err)
-		}
-		num := ReadHeaderNumber(db, common.BytesToHash(h))
-		if num == nil {
-			log.Crit("Missing hash->number mapping", "number", i, "err", err)
-		}
-		if *num != i {
-			log.Crit("Erroneous hash->number mapping", "number", i)
-		}
-	}
 }
 
 type blockTxHashes struct {