diff --git a/tests/server_test.go b/tests/server_test.go
index 58ad05a667..e58d922eac 100644
--- a/tests/server_test.go
+++ b/tests/server_test.go
@@ -9,6 +9,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -27,11 +28,6 @@ func TestMain(m *testing.M) {
 	verboseServerLogs = *vv
 	var r int
 	for _, indexType = range tsdb.RegisteredIndexes() {
-		if indexType != "tsi1" {
-			println("dbg/skipping", indexType)
-			continue
-		}
-
 		// Setup benchmark server
 		c := NewConfig()
 		c.Retention.Enabled = false
@@ -6360,13 +6356,14 @@ func TestServer_Query_Where_With_Tags(t *testing.T) {
 		},
 	}...)
 
-	for i, query := range test.queries {
+	var once sync.Once
+	for _, query := range test.queries {
 		t.Run(query.name, func(t *testing.T) {
-			if i == 0 {
+			once.Do(func() {
 				if err := test.init(s); err != nil {
 					t.Fatalf("test init failed: %s", err)
 				}
-			}
+			})
 			if query.skip {
 				t.Skipf("SKIP:: %s", query.name)
 			}
@@ -8100,13 +8097,14 @@ func TestServer_Query_ShowTagValues(t *testing.T) {
 		},
 	}...)
 
-	for i, query := range test.queries {
+	var once sync.Once
+	for _, query := range test.queries {
 		t.Run(query.name, func(t *testing.T) {
-			if i == 0 {
+			once.Do(func() {
 				if err := test.init(s); err != nil {
 					t.Fatalf("test init failed: %s", err)
 				}
-			}
+			})
 			if query.skip {
 				t.Skipf("SKIP:: %s", query.name)
 			}
diff --git a/tsdb/index.go b/tsdb/index.go
index 950315bf1e..07bfe29cd4 100644
--- a/tsdb/index.go
+++ b/tsdb/index.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"os"
 	"regexp"
+	"runtime/debug"
 	"sort"
 	"sync"
 
@@ -502,11 +503,13 @@ func (itr *seriesIDUnionIterator) Next() (_ SeriesIDElem, err error) {
 	}
 
 	// Return non-zero or lesser series.
-	if a, b := itr.buf[0].SeriesID, itr.buf[1].SeriesID; b == 0 || a < b {
+	if a, b := itr.buf[0].SeriesID, itr.buf[1].SeriesID; a == 0 && b == 0 {
+		return SeriesIDElem{}, nil
+	} else if b == 0 || (a != 0 && a < b) {
 		elem := itr.buf[0]
 		itr.buf[0].SeriesID = 0
 		return elem, nil
-	} else if a == 0 || a > b {
+	} else if a == 0 || (b != 0 && a > b) {
 		elem := itr.buf[1]
 		itr.buf[1].SeriesID = 0
 		return elem, nil
@@ -640,6 +643,7 @@ func NewSeriesPointIterator(sfile *SeriesFile, indexSet IndexSet, fieldset *Meas
 		indexSet: indexSet,
 		fieldset: fieldset,
 		mitr:     mitr,
+		sfile:    sfile,
 		point: query.FloatPoint{
 			Aux: make([]interface{}, len(opt.Aux)),
 		},
@@ -714,6 +718,8 @@ func (itr *seriesPointIterator) Next() (*query.FloatPoint, error) {
 				itr.point.Aux[i] = key
 			}
 		}
+
+		return &itr.point, nil
 	}
 }
 
@@ -1296,7 +1302,7 @@ func (is IndexSet) matchTagValueEqualEmptySeriesIDIterator(name, key []byte, val
 			e, err := vitr.Next()
 			if err != nil {
 				return err
-			} else if e != nil {
+			} else if e == nil {
 				break
 			}
 
@@ -1338,7 +1344,7 @@ func (is IndexSet) matchTagValueEqualNotEmptySeriesIDIterator(name, key []byte,
 		if err != nil {
 			SeriesIDIterators(itrs).Close()
 			return nil, err
-		} else if e != nil {
+		} else if e == nil {
 			break
 		}
 
@@ -1369,7 +1375,7 @@ func (is IndexSet) matchTagValueNotEqualEmptySeriesIDIterator(name, key []byte,
 		if err != nil {
 			SeriesIDIterators(itrs).Close()
 			return nil, err
-		} else if e != nil {
+		} else if e == nil {
 			break
 		}
 
@@ -1400,7 +1406,7 @@ func (is IndexSet) matchTagValueNotEqualNotEmptySeriesIDIterator(name, key []byt
 		if err != nil {
 			SeriesIDIterators(itrs).Close()
 			return nil, err
-		} else if e != nil {
+		} else if e == nil {
 			break
 		}
 		if value.Match(e) {
@@ -1750,3 +1756,7 @@ type byTagKey []*query.TagSet
 func (t byTagKey) Len() int           { return len(t) }
 func (t byTagKey) Less(i, j int) bool { return bytes.Compare(t[i].Key, t[j].Key) < 0 }
 func (t byTagKey) Swap(i, j int)      { t[i], t[j] = t[j], t[i] }
+
+func stack() string {
+	return "------------------------\n" + string(debug.Stack()) + "------------------------\n\n"
+}
diff --git a/tsdb/index/tsi1/partition.go b/tsdb/index/tsi1/partition.go
index a54501c0f8..2c8a059ce3 100644
--- a/tsdb/index/tsi1/partition.go
+++ b/tsdb/index/tsi1/partition.go
@@ -736,15 +736,6 @@ func (i *Partition) UnassignShard(k string, shardID uint64, ts int64) error {
 	return i.DropSeries([]byte(k), ts)
 }
 
-/*
-// seriesIDIterator returns an iterator over all matching series.
-func (i *Partition) seriesPointIterator(opt query.IteratorOptions) tsdb.SeriesIDIterator {
-	// NOTE: The iterator handles releasing the file set.
-	fs := i.RetainFileSet()
-	return newSeriesPointIterator(fs, i.fieldset, opt), nil
-}
-*/
-
 // Compact requests a compaction of log files.
 func (i *Partition) Compact() {
 	i.mu.Lock()
diff --git a/tsdb/store.go b/tsdb/store.go
index c52e781595..710064fb6f 100644
--- a/tsdb/store.go
+++ b/tsdb/store.go
@@ -1266,7 +1266,7 @@ func (s *Store) TagValues(auth query.Authorizer, shardIDs []uint64, cond influxq
 		return e
 	}), nil)
 
-	// Get set of Shards to work on.
+	// Build index set to work on.
 	shards := make([]*Shard, 0, len(shardIDs))
 	s.mu.RLock()
 	for _, sid := range shardIDs {