SHOW TAG VALUES accepts != and !~ in WHERE clause

CHANGELOG.md

@@ -16,6 +16,7 @@
 - [#6604](https://github.com/influxdata/influxdb/pull/6604): Remove old cluster code
 - [#6618](https://github.com/influxdata/influxdb/pull/6618): Optimize shard loading
 - [#6629](https://github.com/influxdata/influxdb/issues/6629): query-log-enabled in config not ignored anymore.
+- [#6607](https://github.com/influxdata/influxdb/issues/6607): SHOW TAG VALUES accepts != and !~ in WHERE clause.
 
 ## v0.13.0 [2016-05-12]
 

cmd/influxd/run/server_test.go

@@ -5496,7 +5496,19 @@ func TestServer_Query_ShowTagKeys(t *testing.T) {
 		&Query{
 			name:    `show tag values with key and where does not match the regular expression`,
 			command: `SHOW TAG VALUES WITH KEY = region WHERE host !~ /server0[12]/`,
-			exp:     `{"results":[{"series":[{"name":"disk","columns":["key","value"],"values":[["region","caeast"]]}]}]}`,
+			exp:     `{"results":[{"series":[{"name":"disk","columns":["key","value"],"values":[["region","caeast"]]},{"name":"gpu","columns":["key","value"],"values":[["region","caeast"]]}]}]}`,
+			params:  url.Values{"db": []string{"db0"}},
+		},
+		&Query{
+			name:    `show tag values with key and where partially matches the regular expression`,
+			command: `SHOW TAG VALUES WITH KEY = host WHERE region =~ /us/`,
+			exp:     `{"results":[{"series":[{"name":"cpu","columns":["key","value"],"values":[["host","server01"],["host","server02"]]},{"name":"gpu","columns":["key","value"],"values":[["host","server02"]]}]}]}`,
+			params:  url.Values{"db": []string{"db0"}},
+		},
+		&Query{
+			name:    `show tag values with key and where partially does not match the regular expression`,
+			command: `SHOW TAG VALUES WITH KEY = host WHERE region !~ /us/`,
+			exp:     `{"results":[{"series":[{"name":"cpu","columns":["key","value"],"values":[["host","server01"]]},{"name":"disk","columns":["key","value"],"values":[["host","server03"]]},{"name":"gpu","columns":["key","value"],"values":[["host","server03"]]}]}]}`,
 			params:  url.Values{"db": []string{"db0"}},
 		},
 		&Query{

tsdb/meta.go

@@ -233,6 +233,10 @@ func (d *DatabaseIndex) TagsForSeries(key string) map[string]string {
 // is true) against when there are no measurements because the expression
 // wasn't evaluated (when the bool is false).
 func (d *DatabaseIndex) measurementsByExpr(expr influxql.Expr) (Measurements, bool, error) {
+	if expr == nil {
+		return nil, false, nil
+	}
+
 	switch e := expr.(type) {
 	case *influxql.BinaryExpr:
 		switch e.Op {
@@ -360,7 +364,7 @@ func (d *DatabaseIndex) measurementsByTagFilters(filters []*TagFilter) Measureme
 					tagMatch = true
 				}
 			} else {
-				// Else, the operator is regex and we have to check all tag
+				// Else, the operator is a regex and we have to check all tag
 				// values against the regular expression.
 				for tagVal := range tagVals {
 					if f.Regex.MatchString(tagVal) {

tsdb/shard.go

@@ -1205,16 +1205,36 @@ func NewTagValuesIterator(sh *Shard, opt influxql.IteratorOptions) (influxql.Ite
 		return nil, errors.New("a condition is required")
 	}
 
-	mms, ok, err := sh.index.measurementsByExpr(opt.Condition)
+	measurementExpr := influxql.CloneExpr(opt.Condition)
+	measurementExpr = influxql.Reduce(influxql.RewriteExpr(measurementExpr, func(e influxql.Expr) influxql.Expr {
+		switch e := e.(type) {
+		case *influxql.BinaryExpr:
+			switch e.Op {
+			case influxql.EQ, influxql.NEQ, influxql.EQREGEX, influxql.NEQREGEX:
+				tag, ok := e.LHS.(*influxql.VarRef)
+				if !ok || tag.Val != "_name" {
+					return nil
+				}
+			}
+		}
+		return e
+	}), nil)
+
+	mms, ok, err := sh.index.measurementsByExpr(measurementExpr)
 	if err != nil {
 		return nil, err
 	} else if !ok {
 		mms = sh.index.Measurements()
 		sort.Sort(mms)
 	}
 
+	// If there are no measurements, return immediately.
+	if len(mms) == 0 {
+		return &tagValuesIterator{}, nil
+	}
+
 	filterExpr := influxql.CloneExpr(opt.Condition)
-	filterExpr = influxql.RewriteExpr(filterExpr, func(e influxql.Expr) influxql.Expr {
+	filterExpr = influxql.Reduce(influxql.RewriteExpr(filterExpr, func(e influxql.Expr) influxql.Expr {
 		switch e := e.(type) {
 		case *influxql.BinaryExpr:
 			switch e.Op {
@@ -1226,7 +1246,7 @@ func NewTagValuesIterator(sh *Shard, opt influxql.IteratorOptions) (influxql.Ite
 			}
 		}
 		return e
-	})
+	}), nil)
 
 	var series []*Series
 	keys := newStringSet()