allow users to specify badger table options (#1188)

allow users to specify badger table options and make it loadtoram by default

cmd/dgraph/main.go

@@ -87,6 +87,10 @@ func setupConfigOpts() {
 	defaults := dgraph.DefaultConfig
 	flag.StringVar(&config.PostingDir, "p", defaults.PostingDir,
 		"Directory to store posting lists.")
+	flag.StringVar(&config.PostingTables, "posting_tables", defaults.PostingTables,
+		"Specifies how Badger LSM tree is stored. Options are loadtoram, memorymap and "+
+			"nothing; which consume most to least RAM while providing best to worst "+
+			"performance respectively.")
 	flag.StringVar(&config.WALDir, "w", defaults.WALDir,
 		"Directory to store raft write-ahead logs.")
 	flag.BoolVar(&config.Nomutations, "nomutations", defaults.Nomutations,

cmd/dgraph/main_test.go

@@ -80,6 +80,7 @@ func prepare() (dir1, dir2 string, ps *badger.KV, rerr error) {
 	}
 
 	dgraph.Config.PostingDir = dir1
+	dgraph.Config.PostingTables = "loadtoram"
 	dgraph.Config.WALDir = dir2
 	dgraph.State = dgraph.NewServerState()
 

dgraph/config.go

@@ -17,17 +17,19 @@
 package dgraph
 
 import (
+	"path/filepath"
+
 	"github.com/dgraph-io/dgraph/posting"
 	"github.com/dgraph-io/dgraph/worker"
 	"github.com/dgraph-io/dgraph/x"
-	"path/filepath"
 )
 
 type Options struct {
-	PostingDir  string
-	WALDir      string
-	Nomutations bool
-	NumPending  int
+	PostingDir    string
+	PostingTables string
+	WALDir        string
+	Nomutations   bool
+	NumPending    int
 
 	AllottedMemory float64
 	CommitFraction float64
@@ -52,10 +54,11 @@ type Options struct {
 var Config Options
 
 var DefaultConfig = Options{
-	PostingDir:  "p",
-	WALDir:      "w",
-	Nomutations: false,
-	NumPending:  1000,
+	PostingDir:    "p",
+	PostingTables: "loadtoram",
+	WALDir:        "w",
+	Nomutations:   false,
+	NumPending:    1000,
 
 	AllottedMemory: 1024.0,
 	CommitFraction: 0.10,

dgraph/server.go

@@ -63,7 +63,7 @@ func (s *ServerState) initStorage() {
 	kvOpt.SyncWrites = true
 	kvOpt.Dir = Config.WALDir
 	kvOpt.ValueDir = Config.WALDir
-	kvOpt.MapTablesTo = table.Nothing
+	kvOpt.MapTablesTo = table.MemoryMap
 
 	var err error
 	s.WALstore, err = badger.NewKV(&kvOpt)
@@ -77,7 +77,16 @@ func (s *ServerState) initStorage() {
 	opt.SyncWrites = true
 	opt.Dir = Config.PostingDir
 	opt.ValueDir = Config.PostingDir
-	opt.MapTablesTo = table.MemoryMap
+	switch Config.PostingTables {
+	case "memorymap":
+		opt.MapTablesTo = table.MemoryMap
+	case "loadtoram":
+		opt.MapTablesTo = table.LoadToRAM
+	case "nothing":
+		opt.MapTablesTo = table.Nothing
+	default:
+		x.Fatalf("Invalid Posting Tables options")
+	}
 	s.Pstore, err = badger.NewKV(&opt)
 	x.Checkf(err, "Error while creating badger KV posting store")
 }