Merge pull request #225 from benbjohnson/no-sync

Add DB.NoSync option for bulk loading.

cmd/bolt/bench.go

@@ -46,6 +46,7 @@ func Bench(options *BenchOptions) {
 		fatal(err)
 		return
 	}
+	db.NoSync = options.NoSync
 	db.FillPercent = options.FillPercent
 	defer db.Close()
 
@@ -363,6 +364,7 @@ type BenchOptions struct {
 	BlockProfile  string
 	StatsInterval time.Duration
 	FillPercent   float64
+	NoSync        bool
 	Clean         bool
 }
 

cmd/bolt/main.go

@@ -118,6 +118,7 @@ func NewApp() *cli.App {
 				&cli.StringFlag{Name: "blockprofile", Usage: "Block profile output path"},
 				&cli.StringFlag{Name: "stats-interval", Value: "0s", Usage: "Continuous stats interval"},
 				&cli.Float64Flag{Name: "fill-percent", Value: bolt.DefaultFillPercent, Usage: "Fill percentage"},
+				&cli.BoolFlag{Name: "no-sync", Usage: "Skip fsync on every commit"},
 				&cli.BoolFlag{Name: "work", Usage: "Print the temp db and do not delete on exit"},
 			},
 			Action: func(c *cli.Context) {
@@ -139,6 +140,7 @@ func NewApp() *cli.App {
 					BlockProfile:  c.String("blockprofile"),
 					StatsInterval: statsInterval,
 					FillPercent:   c.Float64("fill-percent"),
+					NoSync:        c.Bool("no-sync"),
 					Clean:         !c.Bool("work"),
 				})
 			},

db.go

@@ -47,6 +47,15 @@ type DB struct {
 	// amount if you know that your write workloads are mostly append-only.
 	FillPercent float64
 
+	// Setting the NoSync flag will cause the database to skip fsync()
+	// calls after each commit. This can be useful when bulk loading data
+	// into a database and you can restart the bulk load in the event of
+	// a system failure or database corruption. Do not set this flag for
+	// normal use.
+	//
+	// THIS IS UNSAFE. PLEASE USE WITH CAUTION.
+	NoSync bool
+
 	path     string
 	file     *os.File
 	dataref  []byte

tx.go

@@ -425,8 +425,10 @@ func (tx *Tx) write() error {
 		// Update statistics.
 		tx.stats.Write++
 	}
-	if err := fdatasync(tx.db.file); err != nil {
-		return err
+	if !tx.db.NoSync {
+		if err := fdatasync(tx.db.file); err != nil {
+			return err
+		}
 	}
 
 	// Clear out page cache.
@@ -446,8 +448,10 @@ func (tx *Tx) writeMeta() error {
 	if _, err := tx.db.ops.writeAt(buf, int64(p.id)*int64(tx.db.pageSize)); err != nil {
 		return err
 	}
-	if err := fdatasync(tx.db.file); err != nil {
-		return err
+	if !tx.db.NoSync {
+		if err := fdatasync(tx.db.file); err != nil {
+			return err
+		}
 	}
 
 	// Update statistics.