From 2602dd241fc58d40a81d716f3e746457d0d6197b Mon Sep 17 00:00:00 2001
From: mengjingleli <mengjinglei@qiniu.com>
Date: Fri, 4 Dec 2015 15:17:31 +0800
Subject: [PATCH] fix raw math query panic

---
 influxql/ast.go             |  8 +++---
 influxql/ast_test.go        | 54 +++++++++++++++++++++++++++++++++++++
 influxql/result.go          |  3 +++
 tsdb/query_executor_test.go | 18 +++++++++++++
 tsdb/raw.go                 |  6 ++++-
 5 files changed, 84 insertions(+), 5 deletions(-)

diff --git a/influxql/ast.go b/influxql/ast.go
index ef7eeab841..239296f498 100644
--- a/influxql/ast.go
+++ b/influxql/ast.go
@@ -2365,14 +2365,14 @@ func (a Fields) AliasNames() []string {
 func (a Fields) Names() []string {
 	names := []string{}
 	for _, f := range a {
-		var name string
 		switch expr := f.Expr.(type) {
 		case *Call:
-			name = expr.Name
+			names = append(names, expr.Name)
 		case *VarRef:
-			name = expr.Val
+			names = append(names, expr.Val)
+		case *BinaryExpr:
+			names = append(names, walkNames(expr)...)
 		}
-		names = append(names, name)
 	}
 	return names
 }
diff --git a/influxql/ast_test.go b/influxql/ast_test.go
index e532fff53b..c0ee09d2ed 100644
--- a/influxql/ast_test.go
+++ b/influxql/ast_test.go
@@ -807,6 +807,60 @@ func TestReduce(t *testing.T) {
 	}
 }
 
+func Test_fieldsNames(t *testing.T) {
+	for _, test := range []struct {
+		in    []string
+		out   []string
+		alias []string
+	}{
+		{ //case: binary expr(valRef)
+			in:    []string{"value+value"},
+			out:   []string{"value", "value"},
+			alias: []string{""},
+		},
+		{ //case: binary expr + valRef
+			in:    []string{"value+value", "temperature"},
+			out:   []string{"value", "value", "temperature"},
+			alias: []string{"", "temperature"},
+		},
+		{ //case: aggregate expr
+			in:    []string{"mean(value)"},
+			out:   []string{"mean"},
+			alias: []string{"mean"},
+		},
+		{ //case: binary expr(aggregate expr)
+			in:    []string{"mean(value) + max(value)"},
+			out:   []string{"value", "value"},
+			alias: []string{""},
+		},
+		{ //case: binary expr(aggregate expr) + valRef
+			in:    []string{"mean(value) + max(value)", "temperature"},
+			out:   []string{"value", "value", "temperature"},
+			alias: []string{"", "temperature"},
+		},
+		{ //case: mixed aggregate and varRef
+			in:    []string{"mean(value) + temperature"},
+			out:   []string{"value", "temperature"},
+			alias: []string{""},
+		},
+	} {
+		fields := influxql.Fields{}
+		for _, s := range test.in {
+			expr := MustParseExpr(s)
+			fields = append(fields, &influxql.Field{Expr: expr})
+		}
+		got := fields.Names()
+		if !reflect.DeepEqual(got, test.out) {
+			t.Errorf("get fileds name:\nexp=%v\ngot=%v\n", test.out, got)
+		}
+		alias := fields.AliasNames()
+		if !reflect.DeepEqual(alias, test.alias) {
+			t.Errorf("get fileds alias name:\nexp=%v\ngot=%v\n", test.alias, alias)
+		}
+	}
+
+}
+
 // Valuer represents a simple wrapper around a map to implement the influxql.Valuer interface.
 type Valuer map[string]interface{}
 
diff --git a/influxql/result.go b/influxql/result.go
index b6a749ccf5..555f1bbfb2 100644
--- a/influxql/result.go
+++ b/influxql/result.go
@@ -95,6 +95,9 @@ type Processor func(values []interface{}) interface{}
 
 func newEchoProcessor(index int) Processor {
 	return func(values []interface{}) interface{} {
+		if index > len(values)-1 {
+			return nil
+		}
 		return values[index]
 	}
 }
diff --git a/tsdb/query_executor_test.go b/tsdb/query_executor_test.go
index ca41b5cdfd..82c1eb59cf 100644
--- a/tsdb/query_executor_test.go
+++ b/tsdb/query_executor_test.go
@@ -48,6 +48,24 @@ func TestWritePointsAndExecuteQuery(t *testing.T) {
 		t.Fatalf("\nexp: %s\ngot: %s", exepected, got)
 	}
 
+	got = executeAndGetJSON("SELECT mean(value) + mean(value) as value FROM cpu", executor)
+	exepected = `[{"series":[{"name":"cpu","columns":["time","value"],"values":[["1970-01-01T00:00:00Z",2]]}]}]`
+	if exepected != got {
+		t.Fatalf("\nexp: %s\ngot: %s", exepected, got)
+	}
+
+	got = executeAndGetJSON("SELECT value + value FROM cpu", executor)
+	exepected = `[{"series":[{"name":"cpu","columns":["time",""],"values":[["1970-01-01T00:00:01.000000002Z",2],["1970-01-01T00:00:02.000000003Z",2]]}]}]`
+	if exepected != got {
+		t.Fatalf("\nexp: %s\ngot: %s", exepected, got)
+	}
+
+	got = executeAndGetJSON("SELECT value + value as sum FROM cpu", executor)
+	exepected = `[{"series":[{"name":"cpu","columns":["time","sum"],"values":[["1970-01-01T00:00:01.000000002Z",2],["1970-01-01T00:00:02.000000003Z",2]]}]}]`
+	if exepected != got {
+		t.Fatalf("\nexp: %s\ngot: %s", exepected, got)
+	}
+
 	got = executeAndGetJSON("SELECT * FROM cpu GROUP BY *", executor)
 	exepected = `[{"series":[{"name":"cpu","tags":{"host":"server"},"columns":["time","value"],"values":[["1970-01-01T00:00:01.000000002Z",1],["1970-01-01T00:00:02.000000003Z",1]]}]}]`
 	if exepected != got {
diff --git a/tsdb/raw.go b/tsdb/raw.go
index 69b791afb2..514818079d 100644
--- a/tsdb/raw.go
+++ b/tsdb/raw.go
@@ -483,9 +483,13 @@ func (r *limitedRowWriter) processValues(values []*MapperValue) *models.Row {
 	selectFields := make([]string, 0, len(selectNames))
 	aliasFields := make([]string, 0, len(selectNames))
 
-	for i, n := range selectNames {
+	for _, n := range selectNames {
 		if _, found := r.tags[n]; !found {
 			selectFields = append(selectFields, n)
+		}
+	}
+	for i, n := range aliasNames {
+		if _, found := r.tags[n]; !found {
 			aliasFields = append(aliasFields, aliasNames[i])
 		}
 	}