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) {