Order the label name and value queries

Needed for tests and correctness

Author: cevian

pkg/pgmodel/lreader/labels_reader.go

@@ -48,7 +48,7 @@ const (
 	tenantLabelValueQual   = `value = $%d`
 	getLabelNamesForTenant = `
 	SELECT
-		array_agg(keys.key)
+		array_agg(keys.key order by keys.key)
 	FROM (
 		SELECT
 			distinct l.key
@@ -76,7 +76,7 @@ const (
 
 	getLabelValuesForTenant = `
 	SELECT
-		array_agg(l.value)
+		array_agg(l.value order by l.value)
 	FROM _prom_catalog.label l
 	WHERE key = $1 AND
 	EXISTS(

pkg/pgmodel/lreader/labels_reader_test.go

@@ -169,7 +169,7 @@ func TestLabelsReaderLabelsValues(t *testing.T) {
 			name: "Tenant values are filtered when tenant is configured",
 			sqlQueries: []model.SqlQuery{
 				{
-					Sql:     "SELECT array_agg(l.value) FROM _prom_catalog.label l WHERE key = $1 AND EXISTS( SELECT 1 FROM _prom_catalog.series WHERE ( labels @> array[l.id] AND labels && ( SELECT array_agg(id :: INTEGER) FROM _prom_catalog.label WHERE key = '__tenant__' AND ( value = $2 ) )::int[] ) )",
+					Sql:     "SELECT array_agg(l.value order by l.value) FROM _prom_catalog.label l WHERE key = $1 AND EXISTS( SELECT 1 FROM _prom_catalog.series WHERE ( labels @> array[l.id] AND labels && ( SELECT array_agg(id :: INTEGER) FROM _prom_catalog.label WHERE key = '__tenant__' AND ( value = $2 ) )::int[] ) )",
 					Args:    []interface{}{"__tenant__", "a"},
 					Results: model.RowResults{{[]string{"a"}}},
 				},