Wire up tag not null/empty filter

index.go

@@ -210,7 +210,22 @@ func (m measurementIndex) seriesByTags(tags map[string]string) *Series {
 func (m measurementIndex) seriesIDs(filter *Filter) (ids SeriesIDs) {
 	values := m.tagsToSeries[filter.Key]
 	if values != nil {
+		// this is for the value is not null query
+		if filter.Not && filter.Value == "" {
+			for _, v := range values {
+				if ids == nil {
+					ids = v
+				} else {
+					ids.Intersect(v)
+				}
+			}
+			return
+		}
+
+		// get the ids that have the given key/value tag pair
 		ids = SeriesIDs(values[filter.Value])
+
+		// filter out these ids from the entire set if it's a not query
 		if filter.Not {
 			ids = m.ids.Reject(ids)
 		}

index_test.go

@@ -158,7 +158,7 @@ func TestIndex_SeriesIDsWhereFilter(t *testing.T) {
 		// match against no tags
 		{
 			names:  []string{"cpu_load", "redis"},
-			result: []uint32{uint32(1), uint32(2), uint32(3), uint32(4), uint32(5)},
+			result: []uint32{uint32(1), uint32(2), uint32(3), uint32(4), uint32(5), uint32(6)},
 		},
 
 		// match against all tags
@@ -217,6 +217,13 @@ func TestIndex_SeriesIDsWhereFilter(t *testing.T) {
 		},
 
 		// query against a tag NOT null
+		{
+			names: []string{"queue_depth"},
+			filters: []*influxdb.Filter{
+				&influxdb.Filter{Key: "app", Value: "", Not: true},
+			},
+			result: []uint32{uint32(6)},
+		},
 
 		// query against a tag value and a NOT value on the same key
 
@@ -330,6 +337,15 @@ func indexWithFixtureData() *influxdb.Index {
 		return nil
 	}
 
+	s = &influxdb.Series{
+		ID:   uint32(6),
+		Tags: map[string]string{"name": "high priority", "app": "paultown"}}
+
+	added = idx.AddSeries("queue_depth", s)
+	if !added {
+		return nil
+	}
+
 	return idx
 }