lncfg+itest: expose configurable batch-commit-interval

This will permit a greater degree of tuning or customization depending
on various hardware/environmental factors.

channeldb/db.go

@@ -275,6 +275,7 @@ func CreateWithBackend(backend kvdb.Backend, modifiers ...OptionModifier) (*DB,
 	}
 	chanDB.graph = newChannelGraph(
 		chanDB, opts.RejectCacheSize, opts.ChannelCacheSize,
+		opts.BatchCommitInterval,
 	)
 
 	// Synchronize the version of database and apply migrations if needed.

channeldb/graph.go

@@ -185,17 +185,18 @@ type ChannelGraph struct {
 
 // newChannelGraph allocates a new ChannelGraph backed by a DB instance. The
 // returned instance has its own unique reject cache and channel cache.
-func newChannelGraph(db *DB, rejectCacheSize, chanCacheSize int) *ChannelGraph {
+func newChannelGraph(db *DB, rejectCacheSize, chanCacheSize int,
+	batchCommitInterval time.Duration) *ChannelGraph {
 	g := &ChannelGraph{
 		db:          db,
 		rejectCache: newRejectCache(rejectCacheSize),
 		chanCache:   newChannelCache(chanCacheSize),
 	}
 	g.chanScheduler = batch.NewTimeScheduler(
-		db.Backend, &g.cacheMu, 500*time.Millisecond,
+		db.Backend, &g.cacheMu, batchCommitInterval,
 	)
 	g.nodeScheduler = batch.NewTimeScheduler(
-		db.Backend, nil, 500*time.Millisecond,
+		db.Backend, nil, batchCommitInterval,
 	)
 	return g
 }

channeldb/options.go

@@ -31,6 +31,10 @@ type Options struct {
 	// channel cache.
 	ChannelCacheSize int
 
+	// BatchCommitInterval is the maximum duration the batch schedulers will
+	// wait before attempting to commit a pending set of updates.
+	BatchCommitInterval time.Duration
+
 	// clock is the time source used by the database.
 	clock clock.Clock
 
@@ -92,6 +96,14 @@ func OptionAutoCompactMinAge(minAge time.Duration) OptionModifier {
 	}
 }
 
+// OptionSetBatchCommitInterval sets the batch commit interval for the internval
+// batch schedulers.
+func OptionSetBatchCommitInterval(interval time.Duration) OptionModifier {
+	return func(o *Options) {
+		o.BatchCommitInterval = interval
+	}
+}
+
 // OptionClock sets a non-default clock dependency.
 func OptionClock(clock clock.Clock) OptionModifier {
 	return func(o *Options) {

lncfg/db.go

@@ -3,6 +3,7 @@ package lncfg
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"github.com/lightningnetwork/lnd/channeldb/kvdb"
 )
@@ -11,12 +12,15 @@ const (
 	dbName                     = "channel.db"
 	BoltBackend                = "bolt"
 	EtcdBackend                = "etcd"
+	DefaultBatchCommitInterval = 500 * time.Millisecond
 )
 
 // DB holds database configuration for LND.
 type DB struct {
 	Backend string `long:"backend" description:"The selected database backend."`
 
+	BatchCommitInterval time.Duration `long:"batch-commit-interval" description:"The maximum duration the channel graph batch schedulers will wait before attempting to commit a batch of pending updates. This can be tradeoff database contenion for commit latency."`
+
 	Etcd *kvdb.EtcdConfig `group:"etcd" namespace:"etcd" description:"Etcd settings."`
 
 	Bolt *kvdb.BoltConfig `group:"bolt" namespace:"bolt" description:"Bolt settings."`
@@ -26,6 +30,7 @@ type DB struct {
 func DefaultDB() *DB {
 	return &DB{
 		Backend:             BoltBackend,
+		BatchCommitInterval: DefaultBatchCommitInterval,
 		Bolt: &kvdb.BoltConfig{
 			AutoCompactMinAge: kvdb.DefaultBoltAutoCompactMinAge,
 		},

lnd.go

@@ -1381,6 +1381,7 @@ func initializeDatabases(ctx context.Context,
 			databaseBackends.LocalDB,
 			channeldb.OptionSetRejectCacheSize(cfg.Caches.RejectCacheSize),
 			channeldb.OptionSetChannelCacheSize(cfg.Caches.ChannelCacheSize),
+			channeldb.OptionSetBatchCommitInterval(cfg.DB.BatchCommitInterval),
 			channeldb.OptionDryRunMigration(cfg.DryRunMigration),
 		)
 		switch {
@@ -1409,6 +1410,7 @@ func initializeDatabases(ctx context.Context,
 			databaseBackends.LocalDB,
 			channeldb.OptionSetRejectCacheSize(cfg.Caches.RejectCacheSize),
 			channeldb.OptionSetChannelCacheSize(cfg.Caches.ChannelCacheSize),
+			channeldb.OptionSetBatchCommitInterval(cfg.DB.BatchCommitInterval),
 			channeldb.OptionDryRunMigration(cfg.DryRunMigration),
 		)
 		switch {
@@ -1433,6 +1435,7 @@ func initializeDatabases(ctx context.Context,
 		remoteChanDB, err = channeldb.CreateWithBackend(
 			databaseBackends.RemoteDB,
 			channeldb.OptionDryRunMigration(cfg.DryRunMigration),
+			channeldb.OptionSetBatchCommitInterval(cfg.DB.BatchCommitInterval),
 		)
 		switch {
 		case err == channeldb.ErrDryRunMigrationOK:

lntest/itest/lnd_test.go

@@ -1846,12 +1846,11 @@ func getChannelPolicies(t *harnessTest, node *lntest.HarnessNode,
 	}
 	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
 	chanGraph, err := node.DescribeGraph(ctxt, descReq)
-	if err != nil {
+	require.NoError(t.t, err, "unable to query for alice's graph")
-		t.Fatalf("unable to query for alice's graph: %v", err)
-	}
 
 	var policies []*lnrpc.RoutingPolicy
-out:
+	err = wait.NoError(func() error {
+	out:
 		for _, chanPoint := range chanPoints {
 			for _, e := range chanGraph.Edges {
 				if e.ChanPoint != txStr(chanPoint) {
@@ -1859,9 +1858,11 @@ out:
 				}
 
 				if e.Node1Pub == advertisingNode {
-				policies = append(policies, e.Node1Policy)
+					policies = append(policies,
+						e.Node1Policy)
 				} else {
-				policies = append(policies, e.Node2Policy)
+					policies = append(policies,
+						e.Node2Policy)
 				}
 
 				continue out
@@ -1869,9 +1870,13 @@ out:
 
 			// If we've iterated over all the known edges and we weren't
 			// able to find this specific one, then we'll fail.
-		t.Fatalf("did not find edge %v", txStr(chanPoint))
+			return fmt.Errorf("did not find edge %v", txStr(chanPoint))
 		}
 
+		return nil
+	}, defaultTimeout)
+	require.NoError(t.t, err)
+
 	return policies
 }
 

lntest/node.go

@@ -238,6 +238,7 @@ func (cfg NodeConfig) genArgs() []string {
 	args = append(args, "--nobootstrap")
 	args = append(args, "--debuglevel=debug")
 	args = append(args, "--bitcoin.defaultchanconfs=1")
+	args = append(args, fmt.Sprintf("--db.batch-commit-interval=%v", 10*time.Millisecond))
 	args = append(args, fmt.Sprintf("--bitcoin.defaultremotedelay=%v", DefaultCSV))
 	args = append(args, fmt.Sprintf("--rpclisten=%v", cfg.RPCAddr()))
 	args = append(args, fmt.Sprintf("--restlisten=%v", cfg.RESTAddr()))

sample-lnd.conf

@@ -930,6 +930,10 @@ litecoin.node=ltcd
 ; also has experimental support for etcd, a replicated backend.
 ; db.backend=bolt
 
+; The maximum interval the graph database will wait between attempting to flush
+; a batch of modifications to disk. Defaults to 500 milliseconds.
+; db.batch-commit-interval=500ms
+
 [etcd]
 ; Etcd database host.
 ; db.etcd.host=localhost:2379