From 3b884eae30049b3b932282caa7f39dbe339f37cc Mon Sep 17 00:00:00 2001
From: Thomas E Lackey <telackey@bozemanpass.com>
Date: Tue, 14 Mar 2023 22:32:47 -0500
Subject: [PATCH] Add timer and counter for batched write operations. (#337)

* Add timer and counter for batched write operations.

* Tweak comment
---
 ethdb/leveldb/leveldb.go | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/ethdb/leveldb/leveldb.go b/ethdb/leveldb/leveldb.go
index 01398ebb6..704d7547f 100644
--- a/ethdb/leveldb/leveldb.go
+++ b/ethdb/leveldb/leveldb.go
@@ -63,10 +63,12 @@ type Database struct {
 	fn string      // filename for reporting
 	db *leveldb.DB // LevelDB instance
 
-	getTimer    metrics.Timer // Timer/counter for measuring time and invocations of Get().
-	putTimer    metrics.Timer // Timer/counter for measuring time and invocations of Put().
-	deleteTimer metrics.Timer // Timer/counter for measuring time and invocations of Delete().
-	hasTimer    metrics.Timer // Timer/counter for measuring time and invocations of Has().
+	getTimer         metrics.Timer   // Timer/counter for measuring time and invocations of Get().
+	putTimer         metrics.Timer   // Timer/counter for measuring time and invocations of Put().
+	deleteTimer      metrics.Timer   // Timer/counter for measuring time and invocations of Delete().
+	hasTimer         metrics.Timer   // Timer/counter for measuring time and invocations of Has().
+	batchWriteTimer  metrics.Timer   // Timer/counter for measuring time and invocations of batch writes.
+	batchItemCounter metrics.Counter // Counter for measuring number of batched items written.
 
 	compTimeMeter       metrics.Meter // Meter for measuring the total time spent in database compaction
 	compReadMeter       metrics.Meter // Meter for measuring the data read during compaction
@@ -155,6 +157,8 @@ func NewCustom(file string, namespace string, customize func(options *opt.Option
 	ldb.putTimer = metrics.NewRegisteredTimer(namespace+"db/put/time", nil)
 	ldb.deleteTimer = metrics.NewRegisteredTimer(namespace+"db/delete/time", nil)
 	ldb.hasTimer = metrics.NewRegisteredTimer(namespace+"db/has/time", nil)
+	ldb.batchWriteTimer = metrics.NewRegisteredTimer(namespace+"db/batch_write/time", nil)
+	ldb.batchItemCounter = metrics.NewRegisteredCounter(namespace+"db/batch_item/count", nil)
 
 	// Start up the metrics gathering and return
 	go ldb.meter(metricsGatheringInterval)
@@ -232,16 +236,20 @@ func (db *Database) Delete(key []byte) error {
 // database until a final write is called.
 func (db *Database) NewBatch() ethdb.Batch {
 	return &batch{
-		db: db.db,
-		b:  new(leveldb.Batch),
+		db:          db.db,
+		b:           new(leveldb.Batch),
+		writeTimer:  &db.batchWriteTimer,
+		itemCounter: &db.batchItemCounter,
 	}
 }
 
 // NewBatchWithSize creates a write-only database batch with pre-allocated buffer.
 func (db *Database) NewBatchWithSize(size int) ethdb.Batch {
 	return &batch{
-		db: db.db,
-		b:  leveldb.MakeBatch(size),
+		db:          db.db,
+		b:           leveldb.MakeBatch(size),
+		writeTimer:  &db.batchWriteTimer,
+		itemCounter: &db.batchItemCounter,
 	}
 }
 
@@ -493,9 +501,11 @@ func (db *Database) meter(refresh time.Duration) {
 // batch is a write-only leveldb batch that commits changes to its host database
 // when Write is called. A batch cannot be used concurrently.
 type batch struct {
-	db   *leveldb.DB
-	b    *leveldb.Batch
-	size int
+	db          *leveldb.DB
+	b           *leveldb.Batch
+	size        int
+	writeTimer  *metrics.Timer
+	itemCounter *metrics.Counter
 }
 
 // Put inserts the given value into the batch for later committing.
@@ -519,6 +529,12 @@ func (b *batch) ValueSize() int {
 
 // Write flushes any accumulated data to disk.
 func (b *batch) Write() error {
+	if nil != *b.writeTimer {
+		defer func(start time.Time) { (*b.writeTimer).UpdateSince(start) }(time.Now())
+	}
+	if nil != *b.itemCounter {
+		(*b.itemCounter).Inc(int64(b.size))
+	}
 	return b.db.Write(b.b, nil)
 }