From 54688f3266c325fca3c19d7de179cb4ad78f9e6a Mon Sep 17 00:00:00 2001
From: Lonng <chris@lonng.org>
Date: Sun, 30 Dec 2018 09:02:22 +0800
Subject: [PATCH] mydump: set read block buffer size to BlockSize *
 config.BufferSizeScale

---
 go.mod                     | 3 ---
 lightning/config/config.go | 4 ++--
 lightning/config/const.go  | 2 ++
 lightning/metric/metric.go | 4 ++--
 lightning/mydump/parser.go | 5 +++--
 tidb-lightning.toml        | 8 ++++++--
 6 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/go.mod b/go.mod
index 30c72ba50..ae420df0a 100644
--- a/go.mod
+++ b/go.mod
@@ -12,11 +12,8 @@ require (
 	github.com/cznic/y v0.0.0-20160420101755-9fdf92d4aac0
 	github.com/go-sql-driver/mysql v1.4.0
 	github.com/gogo/protobuf v1.1.1
-	github.com/google/pprof v0.0.0-20181206194817-3ea8567a2e57 // indirect
-	github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6 // indirect
 	github.com/joho/sqltocsv v0.0.0-20180904231936-b24deec2b806
 	github.com/pingcap/check v0.0.0-20171206051426-1c287c953996
-	github.com/pingcap/errors v0.11.0
 	github.com/pingcap/gofail v0.0.0-20181121072748-c3f835e5a7d8
 	github.com/pingcap/kvproto v0.0.0-20181105061835-1b5d69cd1d26
 	github.com/pingcap/parser v0.0.0-20181113072426-4a9a1b13b591
diff --git a/lightning/config/config.go b/lightning/config/config.go
index 496331a3a..ba1bd4447 100644
--- a/lightning/config/config.go
+++ b/lightning/config/config.go
@@ -71,7 +71,7 @@ type Lightning struct {
 	common.LogConfig
 	TableConcurrency  int  `toml:"table-concurrency" json:"table-concurrency"`
 	RegionConcurrency int  `toml:"region-concurrency" json:"region-concurrency"`
-	IOConcurrency     int  `toml:"io-concurrency" json:"region-concurrency"`
+	IOConcurrency     int  `toml:"io-concurrency" json:"io-concurrency"`
 	ProfilePort       int  `toml:"pprof-port" json:"pprof-port"`
 	CheckRequirements bool `toml:"check-requirements" json:"check-requirements"`
 }
@@ -130,7 +130,7 @@ func NewConfig() *Config {
 		App: Lightning{
 			RegionConcurrency: runtime.NumCPU(),
 			TableConcurrency:  8,
-			IOConcurrency:     2,
+			IOConcurrency:     5,
 			CheckRequirements: true,
 		},
 		TiDB: DBStore{
diff --git a/lightning/config/const.go b/lightning/config/const.go
index 48c70441d..f7769a771 100644
--- a/lightning/config/const.go
+++ b/lightning/config/const.go
@@ -9,6 +9,8 @@ const (
 	ReadBlockSize int64 = 64 * _K
 	MinRegionSize int64 = 256 * _M
 
+	BufferSizeScale = 5
+
 	// kv import
 	KVMaxBatchSize int64 = 200 * _G
 )
diff --git a/lightning/metric/metric.go b/lightning/metric/metric.go
index b2a8c75cf..f2d7135f7 100644
--- a/lightning/metric/metric.go
+++ b/lightning/metric/metric.go
@@ -106,7 +106,7 @@ var (
 		prometheus.HistogramOpts{
 			Namespace: "lightning",
 			Name:      "chunk_parser_read_block_seconds",
-			Help:      "time needed to chunk parser read a block",
+			Help:      "time needed for chunk parser read a block",
 			Buckets:   prometheus.ExponentialBuckets(0.001, 3.1622776601683795, 10),
 		},
 	)
@@ -114,7 +114,7 @@ var (
 		prometheus.HistogramOpts{
 			Namespace: "lightning",
 			Name:      "chunk_parser_read_row_seconds",
-			Help:      "time needed to chunk parser read a row",
+			Help:      "time needed for chunk parser read a row",
 			Buckets:   prometheus.ExponentialBuckets(0.001, 3.1622776601683795, 10),
 		},
 	)
diff --git a/lightning/mydump/parser.go b/lightning/mydump/parser.go
index 1281cf383..8a2d7598b 100644
--- a/lightning/mydump/parser.go
+++ b/lightning/mydump/parser.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/pkg/errors"
 
+	"github.com/pingcap/tidb-lightning/lightning/config"
 	"github.com/pingcap/tidb-lightning/lightning/metric"
 	"github.com/pingcap/tidb-lightning/lightning/worker"
 )
@@ -54,7 +55,7 @@ type Row struct {
 func NewChunkParser(reader io.Reader, blockBufSize int64, ioWorkers *worker.RestoreWorkerPool) *ChunkParser {
 	return &ChunkParser{
 		reader:    reader,
-		blockBuf:  make([]byte, blockBufSize),
+		blockBuf:  make([]byte, blockBufSize*config.BufferSizeScale),
 		remainBuf: &bytes.Buffer{},
 		appendBuf: &bytes.Buffer{},
 		ioWorkers: ioWorkers,
@@ -92,7 +93,7 @@ func (parser *ChunkParser) readBlock() error {
 	// limit IO concurrency
 	w := parser.ioWorkers.Apply()
 	n, err := parser.reader.Read(parser.blockBuf)
-	defer parser.ioWorkers.Recycle(w)
+	parser.ioWorkers.Recycle(w)
 
 	switch err {
 	case io.ErrUnexpectedEOF, io.EOF:
diff --git a/tidb-lightning.toml b/tidb-lightning.toml
index 04ac40c36..c1247e9c2 100644
--- a/tidb-lightning.toml
+++ b/tidb-lightning.toml
@@ -13,8 +13,12 @@ table-concurrency = 8
 # In mixed configuration, you can set it to 75% of the size of logical CPU cores.
 # region-concurrency default to runtime.NumCPU()
 # region-concurrency =
-# io-concurrency controls the maximum io concurrent
-# io-concurrency = 2
+# io-concurrency controls the maximum IO concurrency
+# Excessive IO concurrency causes an increase in IO latency because the disk
+# internal buffer is frequently refreshed causing a cache miss. For different
+# disk media, concurrency has different effects on IO latency, which can be
+# adjusted according to monitoring.
+# io-concurrency = 5
 
 # logging
 level = "info"