fix issue #4816 some aggregate function work incorrectly in cluster mode

CHANGELOG.md

@@ -12,6 +12,7 @@
 - [#4804](https://github.com/influxdb/influxdb/pull/4804): Complete lint for services/admin. Thanks @nii236
 - [#4796](https://github.com/influxdb/influxdb/pull/4796): Check point without fields. Thanks @CrazyJvm
 - [#4815](https://github.com/influxdb/influxdb/pull/4815): Added `Time` field into aggregate output across the cluster. Thanks @li-ang
+- [#4817](https://github.com/influxdb/influxdb/pull/4817): Fix Min,Max,Top,Bottom function when query distributed node. Thanks @mengjinglei
 
 ## v0.9.5 [2015-11-20]
 

tsdb/functions.go

@@ -199,6 +199,21 @@ func InitializeUnmarshaller(c *influxql.Call) (UnmarshalFunc, error) {
 			err := json.Unmarshal(b, &o)
 			return &o, err
 		}, nil
+	case "min", "max":
+		return func(b []byte) (interface{}, error) {
+			if string(b) == "null" {
+				return nil, nil
+			}
+			var o minMaxMapOut
+			err := json.Unmarshal(b, &o)
+			return &o, err
+		}, nil
+	case "top", "bottom":
+		return func(b []byte) (interface{}, error) {
+			var o PositionPoints
+			err := json.Unmarshal(b, &o)
+			return o, err
+		}, nil
 	case "spread":
 		return func(b []byte) (interface{}, error) {
 			var o spreadMapOutput

tsdb/functions_test.go

@@ -863,3 +863,132 @@ func TestReduceTopBottom(t *testing.T) {
 		}
 	}
 }
+
+func TestInitializeUnmarshallerMaxMin(t *testing.T) {
+	tests := []struct {
+		Name   string
+		input  []byte
+		output interface{}
+		call   *influxql.Call
+	}{
+		{
+			Name:  "max - one point",
+			input: []byte(`{"Time":1447729856247384906,"Val":1,"Type":0,"Fields":{"":1},"Tags":{}}`),
+			output: PositionPoint{
+				Time:   int64(1447729856247384906),
+				Value:  float64(1),
+				Fields: map[string]interface{}{"": float64(1)},
+				Tags:   map[string]string{},
+			},
+			call: &influxql.Call{Name: "max"},
+		},
+		{
+			Name:   "max - nil point",
+			input:  []byte(`null`),
+			output: nil,
+			call:   &influxql.Call{Name: "max"},
+		},
+		{
+			Name:  "min - one point",
+			input: []byte(`{"Time":1447729856247384906,"Val":1,"Type":0,"Fields":{"":1},"Tags":{}}`),
+			output: PositionPoint{
+				Time:   int64(1447729856247384906),
+				Value:  float64(1),
+				Fields: map[string]interface{}{"": float64(1)},
+				Tags:   map[string]string{},
+			},
+			call: &influxql.Call{Name: "min"},
+		},
+		{
+			Name:   "min - nil point",
+			input:  []byte(`null`),
+			output: nil,
+			call:   &influxql.Call{Name: "min"},
+		},
+	}
+	for _, test := range tests {
+		unmarshaller, err := InitializeUnmarshaller(test.call)
+		if err != nil {
+			t.Errorf("initialize unmarshaller for %v, got error:%v", test.Name, err)
+		}
+
+		// unmarshaller take bytes recieved from remote server as input,
+		// unmarshal it into an interface the reducer can use
+		unmarshallOutput, err := unmarshaller(test.input)
+		if err != nil {
+			t.Errorf("unmarshaller unmarshal %v fail with error:%v", &test.input, err)
+		}
+
+		//if input is "null" then the unmarshal output is expect to be nil
+		if string(test.input) == "null" && unmarshallOutput != nil {
+			t.Errorf("initialize unmarshaller, \nexp\n %v\ngot\n %v", nil, spew.Sdump(unmarshallOutput))
+			continue
+		}
+
+		// initialize a reducer that can take the output of unmarshaller as input
+		reducer, err := initializeReduceFunc(test.call)
+		if err != nil {
+			t.Errorf("initialize %v reduce function fail with error:%v", test.Name, err)
+		}
+
+		output := reducer([]interface{}{unmarshallOutput})
+		if !reflect.DeepEqual(output, test.output) {
+			t.Errorf("Wrong output. \nexp\n %v\ngot\n %v", spew.Sdump(test.output), spew.Sdump(output))
+		}
+	}
+}
+
+func TestInitializeUnmarshallerTopBottom(t *testing.T) {
+	tests := []struct {
+		Name   string
+		input  []byte
+		output interface{}
+		call   *influxql.Call
+	}{
+		{
+			Name:  "top - one point",
+			input: []byte(`[{"Time":1447729856247384906,"Value":1,"Fields":{"":1},"Tags":{}}]`),
+			output: PositionPoints{
+				{int64(1447729856247384906), float64(1), map[string]interface{}{"": float64(1)}, map[string]string{}},
+			},
+			call: &influxql.Call{
+				Name: "top",
+				Args: []influxql.Expr{
+					&influxql.VarRef{Val: "field1"},
+					&influxql.NumberLiteral{Val: 1},
+				},
+			},
+		},
+		{
+			Name:  "bottom - one point",
+			input: []byte(`[{"Time":1447729856247384906,"Value":1,"Fields":{"":1},"Tags":{}}]`),
+			output: PositionPoints{
+				{int64(1447729856247384906), float64(1), map[string]interface{}{"": float64(1)}, map[string]string{}},
+			},
+			call: &influxql.Call{
+				Name: "bottom",
+				Args: []influxql.Expr{
+					&influxql.VarRef{Val: "field1"},
+					&influxql.NumberLiteral{Val: 1},
+				},
+			},
+		},
+	}
+	for _, test := range tests {
+		unmarshaller, err := InitializeUnmarshaller(test.call)
+		if err != nil {
+			t.Errorf("initialize unmarshaller for %v, got error:%v", test.Name, err)
+		}
+
+		// unmarshaller take bytes recieved from remote server as input,
+		// unmarshal it into an interface the reducer can use
+		output, err := unmarshaller(test.input)
+		if err != nil {
+			t.Errorf("unmarshaller unmarshal %v fail with error:%v", &test.input, err)
+		}
+
+		if !reflect.DeepEqual(output, test.output) {
+			t.Errorf("Wrong output. \nexp\n %v\ngot\n %v", spew.Sdump(test.output), spew.Sdump(output))
+		}
+	}
+}