From 9860f845fe5c2d879634cccc2cada2091664636f Mon Sep 17 00:00:00 2001
From: Alex Sharov <AskAlexSharov@gmail.com>
Date: Mon, 3 Oct 2022 16:53:23 +0700
Subject: [PATCH] mdbx mergeThreshold option #665

---
 kv/mdbx/kv_mdbx.go | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/kv/mdbx/kv_mdbx.go b/kv/mdbx/kv_mdbx.go
index 6c09615bc..06512ecfc 100644
--- a/kv/mdbx/kv_mdbx.go
+++ b/kv/mdbx/kv_mdbx.go
@@ -59,7 +59,12 @@ type MdbxOpts struct {
 	syncPeriod    time.Duration
 	augumentLimit uint64
 	pageSize      uint64
-	roTxsLimiter  *semaphore.Weighted
+
+	// must be in the range from 12.5% (almost empty) to 50% (half empty)
+	// which corresponds to the range from 8192 and to 32768 in units respectively
+	mergeThreshold uint64
+
+	roTxsLimiter *semaphore.Weighted
 }
 
 func testKVPath() string {
@@ -72,11 +77,12 @@ func testKVPath() string {
 
 func NewMDBX(log log.Logger) MdbxOpts {
 	return MdbxOpts{
-		bucketsCfg: WithChaindataTables,
-		flags:      mdbx.NoReadahead | mdbx.Coalesce | mdbx.Durable,
-		log:        log,
-		pageSize:   kv.DefaultPageSize(),
-		growthStep: 2 * datasize.GB,
+		bucketsCfg:     WithChaindataTables,
+		flags:          mdbx.NoReadahead | mdbx.Coalesce | mdbx.Durable,
+		log:            log,
+		pageSize:       kv.DefaultPageSize(),
+		growthStep:     2 * datasize.GB,
+		mergeThreshold: 32768,
 	}
 }
 
@@ -160,6 +166,11 @@ func (opts MdbxOpts) WriteMap() MdbxOpts {
 	return opts
 }
 
+func (opts MdbxOpts) WriteMergeThreshold(v uint64) MdbxOpts {
+	opts.mergeThreshold = v
+	return opts
+}
+
 func (opts MdbxOpts) WithTableCfg(f TableCfgFunc) MdbxOpts {
 	opts.bucketsCfg = f
 	return opts
@@ -263,7 +274,7 @@ func (opts MdbxOpts) Open() (kv.RwDB, error) {
 		}
 		// must be in the range from 12.5% (almost empty) to 50% (half empty)
 		// which corresponds to the range from 8192 and to 32768 in units respectively
-		if err = env.SetOption(mdbx.OptMergeThreshold16dot16Percent, 32768); err != nil {
+		if err = env.SetOption(mdbx.OptMergeThreshold16dot16Percent, opts.mergeThreshold); err != nil {
 			return nil, err
 		}
 	}