coprocessor: skip empty tidb nodes

infoschema/cluster_tables_test.go

@@ -237,6 +237,7 @@ func TestSelectClusterTable(t *testing.T) {
 	tk.MustExec("use information_schema")
 	tk.MustExec("set @@global.tidb_enable_stmt_summary=1")
 	tk.MustExec("set time_zone = '+08:00';")
+	// TODO
 	tk.MustQuery("select count(*) from `CLUSTER_SLOW_QUERY`").Check(testkit.Rows("2"))
 	tk.MustQuery("select time from `CLUSTER_SLOW_QUERY` where time='2019-02-12 19:33:56.571953'").Check(testkit.RowsWithSep("|", "2019-02-12 19:33:56.571953"))
 	tk.MustQuery("select count(*) from `CLUSTER_PROCESSLIST`").Check(testkit.Rows("1"))

store/copr/coprocessor.go

@@ -265,6 +265,13 @@ func buildTiDBMemCopTasks(ranges *KeyRanges, req *kv.Request) ([]*copTask, error
 			continue
 		}
 
+		// Some components (like BR) will register tidb nodes with empty IP
+		// addresses in etcd, which will cause cop requests to time out. We
+		// avoid this problem when building cop tasks.
+		if ser.IP == "" {
+			continue
+		}
+
 		addr := ser.IP + ":" + strconv.FormatUint(uint64(ser.StatusPort), 10)
 		tasks = append(tasks, &copTask{
 			ranges:    ranges,

tests/realtikvtest/sessiontest/session_fail_test.go

@@ -133,8 +133,9 @@ func TestClusterTableSendError(t *testing.T) {
 	require.NoError(t, failpoint.Enable("tikvclient/tikvStoreSendReqResult", `return("requestTiDBStoreError")`))
 	defer func() { require.NoError(t, failpoint.Disable("tikvclient/tikvStoreSendReqResult")) }()
 	tk.MustQuery("select * from information_schema.cluster_slow_query")
-	require.Equal(t, tk.Session().GetSessionVars().StmtCtx.WarningCount(), uint16(1))
-	require.Regexp(t, ".*TiDB server timeout, address is.*", tk.Session().GetSessionVars().StmtCtx.GetWarnings()[0].Err.Error())
+	// Since we avoid making requests to empty addresses, there will be no warnings here.
+	// See: https://github.com/pingcap/tidb/pull/36548
+	require.Equal(t, tk.Session().GetSessionVars().StmtCtx.WarningCount(), uint16(0))
 }
 
 func TestAutoCommitNeedNotLinearizability(t *testing.T) {