From bfda9bc731dd6a3cf5a369a0d2f6ed5cd97ab3f9 Mon Sep 17 00:00:00 2001
From: "alex.sharov" <AskAlexSharov@gmail.com>
Date: Wed, 16 Nov 2022 09:43:56 +0300
Subject: [PATCH] save

---
 common/debug/experiments.go | 22 ++++++++++++++++++++++
 node/node.go                |  5 ++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/common/debug/experiments.go b/common/debug/experiments.go
index 5f2a87f5c..a0306c649 100644
--- a/common/debug/experiments.go
+++ b/common/debug/experiments.go
@@ -22,6 +22,28 @@ func WriteMap() bool {
 	return writeMap
 }
 
+var (
+	mergeTr     int
+	mergeTrOnce sync.Once
+)
+
+func MergeTr() int {
+	mergeTrOnce.Do(func() {
+		v, _ := os.LookupEnv("MERGE_THRESHOLD")
+		if v != "" {
+			i, err := strconv.Atoi(v)
+			if err != nil {
+				panic(err)
+			}
+			if i < 0 || i > 4 {
+				panic(i)
+			}
+			mergeTr = i
+		}
+	})
+	return mergeTr
+}
+
 var (
 	mdbxReaadahead     bool
 	mdbxReaadaheadOnce sync.Once
diff --git a/node/node.go b/node/node.go
index 99fc14349..4a0860fa9 100644
--- a/node/node.go
+++ b/node/node.go
@@ -340,7 +340,10 @@ func OpenDatabase(config *nodecfg.Config, logger log.Logger, label kv.Label) (kv
 			opts = opts.GrowthStep(16 * datasize.MB)
 		}
 		if debug.WriteMap() {
-			opts = opts.WriteMap().WriteMergeThreshold(1 * 8192)
+			opts = opts.WriteMap()
+		}
+		if debug.MergeTr() > 0 {
+			opts = opts.WriteMergeThreshold(uint64(debug.MergeTr() * 8192))
 		}
 		if debug.MdbxReadAhead() {
 			opts = opts.Flags(func(u uint) uint {