fix #442. Fix some bugs in shouldQuerySequentially and add a test

src/coordinator/coordinator.go

@@ -215,7 +215,7 @@ func (self *CoordinatorImpl) shouldAggregateLocally(shards []*cluster.ShardData,
 
 func (self *CoordinatorImpl) shouldQuerySequentially(shards []*cluster.ShardData, querySpec *parser.QuerySpec) bool {
 	// if the query isn't a select, then it doesn't matter
-	if querySpec.SelectQuery != nil {
+	if querySpec.SelectQuery() == nil {
 		return false
 	}
 
@@ -244,6 +244,10 @@ func (self *CoordinatorImpl) shouldQuerySequentially(shards []*cluster.ShardData
 		return true
 	}
 
+	if !self.shouldAggregateLocally(shards, querySpec) {
+		return true
+	}
+
 	for _, shard := range shards {
 		bufferSize := shard.QueryResponseBufferSize(querySpec, self.config.LevelDbPointBatchSize)
 		// if the number of repsonses is too big, do a sequential querying

src/coordinator/coordinator_test.go

@@ -0,0 +1,42 @@
+package coordinator
+
+import (
+	"cluster"
+	"configuration"
+	"fmt"
+	"parser"
+	"time"
+	. "launchpad.net/gocheck"
+)
+
+type CoordinatorSuite struct{}
+
+var _ = Suite(&CoordinatorSuite{})
+
+func (self *CoordinatorSuite) TestShouldQuerySequentially(c *C) {
+	end := time.Now().Truncate(24 * time.Hour)
+	start := end.Add(-7 * 24 * time.Hour)
+	shard := cluster.NewShard(1, start, end, cluster.SHORT_TERM, false, nil)
+	shards := []*cluster.ShardData{shard}
+	coordinator := NewCoordinatorImpl(&configuration.Configuration{
+		ClusterMaxResponseBufferSize: 1000,
+	}, nil, nil)
+	queries := map[string]bool{
+		"list series": false,
+		"select count(foo) from /.*bar.*/ group by time(1d)": true,
+		"select count(foo) from bar":                         true,
+		"select foo from bar":                                true,
+		"select count(foo) from bar group by baz":            true,
+		"select count(foo) from bar group by time(1d)":       false,
+		"select count(foo) from bar group by time(3d)":       true,
+	}
+
+	for query, result := range queries {
+		fmt.Printf("Testing %s\n", query)
+		parsedQuery, err := parser.ParseQuery(query)
+		c.Assert(err, IsNil)
+		c.Assert(parsedQuery, HasLen, 1)
+		querySpec := parser.NewQuerySpec(nil, "", parsedQuery[0])
+		c.Assert(coordinator.shouldQuerySequentially(shards, querySpec), Equals, result)
+	}
+}