server: support batch grpc messages.

src/server/metrics.rs

@@ -16,6 +16,7 @@ use prometheus_static_metric::*;
 
 make_static_metric! {
     pub label_enum GrpcTypeKind {
+        invalid,
         kv_get,
         kv_scan,
         kv_prewrite,
@@ -75,6 +76,16 @@ lazy_static! {
         "Total number of handle grpc message failure",
         &["type"]
     ).unwrap();
+    pub static ref GRPC_REQ_BATCH_COMMANDS_SIZE: Histogram = register_histogram!(
+        "tikv_server_grpc_req_batch_size",
+        "grpc batch size of gRPC requests",
+        exponential_buckets(1f64, 2f64, 10).unwrap()
+    ).unwrap();
+    pub static ref GRPC_RESP_BATCH_COMMANDS_SIZE: Histogram = register_histogram!(
+        "tikv_server_grpc_resp_batch_size",
+        "grpc batch size of gRPC responses",
+        exponential_buckets(1f64, 2f64, 10).unwrap()
+    ).unwrap();
     pub static ref RAFT_MESSAGE_RECV_COUNTER: IntCounter = register_int_counter!(
         "tikv_server_raft_message_recv_total",
         "Total number of raft messages received"

src/server/server.rs

@@ -98,7 +98,15 @@ impl<T: RaftStoreRouter, S: StoreAddrResolver + 'static> Server<T, S> {
         );
         let snap_worker = Worker::new("snap-handler");
 
-        let kv_service = KvService::new(storage, cop, raft_router.clone(), snap_worker.scheduler());
+        let kv_service = KvService::new(
+            storage,
+            cop,
+            raft_router.clone(),
+            snap_worker.scheduler(),
+            Arc::clone(&stats_runtime),
+            Arc::clone(&thread_load),
+        );
+
         let addr = SocketAddr::from_str(&cfg.addr)?;
         info!("listening on {}", addr);
         let ip = format!("{}", addr.ip());
@@ -107,6 +115,7 @@ impl<T: RaftStoreRouter, S: StoreAddrResolver + 'static> Server<T, S> {
             .max_concurrent_stream(cfg.grpc_concurrent_stream)
             .max_receive_message_len(MAX_GRPC_RECV_MSG_LEN)
             .max_send_message_len(-1)
+            .http2_max_ping_strikes(i32::MAX) // For pings without data from clients.
             .build_args();
         let grpc_server = {
             let mut sb = ServerBuilder::new(Arc::clone(&env))