diff --git a/src/dbnode/storage/shard_insert_queue_test.go b/src/dbnode/storage/shard_insert_queue_test.go
index be692ba209..df3a76b3c6 100644
--- a/src/dbnode/storage/shard_insert_queue_test.go
+++ b/src/dbnode/storage/shard_insert_queue_test.go
@@ -48,8 +48,8 @@ func TestShardInsertQueueBatchBackoff(t *testing.T) {
 			currTime = currTime.Add(d)
 		}
 		backoff           = 10 * time.Millisecond
-		insertWgs         [3]sync.WaitGroup
-		insertProgressWgs [3]sync.WaitGroup
+		insertWgs         [64]sync.WaitGroup
+		insertProgressWgs [64]sync.WaitGroup
 	)
 	for i := range insertWgs {
 		insertWgs[i].Add(1)
@@ -146,7 +146,7 @@ func TestShardInsertQueueRateLimit(t *testing.T) {
 		return currTime
 	}, tally.NoopScope, zap.NewNop())
 
-	q.insertPerSecondLimit = 2
+	q.insertPerSecondLimit.Store(2)
 
 	require.NoError(t, q.Start())
 	defer func() {
diff --git a/src/dbnode/x/tchannel/options.go b/src/dbnode/x/tchannel/options.go
index d8e29537c7..1832884935 100644
--- a/src/dbnode/x/tchannel/options.go
+++ b/src/dbnode/x/tchannel/options.go
@@ -29,6 +29,9 @@ import (
 const (
 	defaultIdleCheckInterval = 5 * time.Minute
 	defaultMaxIdleTime       = 5 * time.Minute
+	// defaultSendBufferSize sets the default send buffer size,
+	// by default only 512 frames would be buffered.
+	defaultSendBufferSize = 16384
 )
 
 // NewDefaultChannelOptions returns the default tchannel options used.
@@ -37,5 +40,8 @@ func NewDefaultChannelOptions() *tchannel.ChannelOptions {
 		Logger:            NewNoopLogger(),
 		MaxIdleTime:       defaultMaxIdleTime,
 		IdleCheckInterval: defaultIdleCheckInterval,
+		DefaultConnectionOptions: tchannel.ConnectionOptions{
+			SendBufferSize: defaultSendBufferSize,
+		},
 	}
 }