From 263a9e35838c7261d7fd6b455cac976c8b66f8c3 Mon Sep 17 00:00:00 2001
From: Alex Sharov <AskAlexSharov@gmail.com>
Date: Wed, 7 Dec 2022 16:35:55 +0700
Subject: [PATCH] mdbx: dirtySpace option expose (#770)

---
 common/dbg/experiments.go | 20 ++++++++++++++++++++
 kv/mdbx/kv_mdbx.go        | 19 ++++++++++++++++---
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/common/dbg/experiments.go b/common/dbg/experiments.go
index c911115a8..a9e26db88 100644
--- a/common/dbg/experiments.go
+++ b/common/dbg/experiments.go
@@ -58,6 +58,26 @@ func WriteMap() bool {
 	return writeMap
 }
 
+var (
+	dirtySace     uint64
+	dirtySaceOnce sync.Once
+)
+
+func DirtySpace() uint64 {
+	dirtySaceOnce.Do(func() {
+		v, _ := os.LookupEnv("MDBX_DIRTY_SPACE_MB")
+		if v != "" {
+			i, err := strconv.Atoi(v)
+			if err != nil {
+				panic(err)
+			}
+			dirtySace = uint64(i * 1024 * 1024)
+			log.Info("[Experiment]", "MDBX_DIRTY_SPACE_MB", dirtySace)
+		}
+	})
+	return dirtySace
+}
+
 var (
 	noSync     bool
 	noSyncOnce sync.Once
diff --git a/kv/mdbx/kv_mdbx.go b/kv/mdbx/kv_mdbx.go
index 5fc01b651..3af51ae96 100644
--- a/kv/mdbx/kv_mdbx.go
+++ b/kv/mdbx/kv_mdbx.go
@@ -60,6 +60,7 @@ type MdbxOpts struct {
 	growthStep     datasize.ByteSize
 	flags          uint
 	pageSize       uint64
+	dirtySpace     uint64 // if exeed this space, modified pages will `spill` to disk
 	mergeThreshold uint64
 	verbosity      kv.DBVerbosityLvl
 	label          kv.Label // marker to distinct db instances - one process may open many databases. for example to collect metrics of only 1 database
@@ -72,6 +73,7 @@ func NewMDBX(log log.Logger) MdbxOpts {
 		flags:          mdbx.NoReadahead | mdbx.Coalesce | mdbx.Durable,
 		log:            log,
 		pageSize:       kv.DefaultPageSize(),
+		dirtySpace:     2 * (memory.TotalMemory() / 42),
 		growthStep:     2 * datasize.GB,
 		mergeThreshold: 32768,
 	}
@@ -87,6 +89,11 @@ func (opts MdbxOpts) Label(label kv.Label) MdbxOpts {
 	return opts
 }
 
+func (opts MdbxOpts) DirtySpace(s uint64) MdbxOpts {
+	opts.dirtySpace = s
+	return opts
+}
+
 func (opts MdbxOpts) RoTxsLimiter(l *semaphore.Weighted) MdbxOpts {
 	opts.roTxsLimiter = l
 	return opts
@@ -177,12 +184,18 @@ func (opts MdbxOpts) Open() (kv.RwDB, error) {
 	if dbg.WriteMap() {
 		opts = opts.WriteMap() //nolint
 	}
+	if dbg.DirtySpace() > 0 {
+		opts = opts.DirtySpace(dbg.DirtySpace()) //nolint
+	}
 	if dbg.NoSync() {
 		opts = opts.Flags(func(u uint) uint { return u | mdbx.SafeNoSync }) //nolint
 	}
 	if dbg.MergeTr() > 0 {
 		opts = opts.WriteMergeThreshold(uint64(dbg.MergeTr() * 8192)) //nolint
 	}
+	if dbg.MergeTr() > 0 {
+		opts = opts.WriteMergeThreshold(uint64(dbg.MergeTr() * 8192)) //nolint
+	}
 	if dbg.MdbxReadAhead() {
 		opts = opts.Flags(func(u uint) uint { return u &^ mdbx.NoReadahead }) //nolint
 	}
@@ -271,7 +284,7 @@ func (opts MdbxOpts) Open() (kv.RwDB, error) {
 
 		// default is (TOTAL_RAM+AVAILABLE_RAM)/42/pageSize
 		// but for reproducibility of benchmarks - please don't rely on Available RAM
-		if err = env.SetOption(mdbx.OptTxnDpLimit, 2*(memory.TotalMemory()/42/opts.pageSize)); err != nil {
+		if err = env.SetOption(mdbx.OptTxnDpLimit, opts.dirtySpace/opts.pageSize); err != nil {
 			return nil, err
 		}
 		// must be in the range from 12.5% (almost empty) to 50% (half empty)
@@ -347,7 +360,7 @@ func (opts MdbxOpts) Open() (kv.RwDB, error) {
 		if staleReaders, err := db.env.ReaderCheck(); err != nil {
 			db.log.Error("failed ReaderCheck", "err", err)
 		} else if staleReaders > 0 {
-			db.log.Info("[db] cleared reader slots from dead processes", "amount", staleReaders)
+			db.log.Info("cleared reader slots from dead processes", "amount", staleReaders)
 		}
 
 	}
@@ -604,7 +617,7 @@ func (tx *MdbxTx) CollectMetrics() {
 		if staleReaders, err := tx.db.env.ReaderCheck(); err != nil {
 			tx.db.log.Error("failed ReaderCheck", "err", err)
 		} else if staleReaders > 0 {
-			tx.db.log.Info("[db] cleared reader slots from dead processes", "amount", staleReaders)
+			tx.db.log.Info("cleared reader slots from dead processes", "amount", staleReaders)
 		}
 	}