sorted/kvtest: close iterator ASAP to make sqlite happy

Change-Id: I7dcca4447bea262fedc6a5fbe572034bfd8cc61d

pkg/sorted/kvtest/kvtest.go

@@ -96,12 +96,14 @@ func testInsertLarge(t *testing.T, kv sorted.KeyValue) {
 	if err := kv.Set(string(largeKey), "whatever"); err != nil {
 		t.Fatalf("Insertion of large key failed: %v", err)
 	}
+
 	// and verify we can get it back, i.e. that the key hasn't been truncated.
 	it := kv.Find(string(largeKey), "")
-	defer it.Close()
 	if !it.Next() || it.Key() != string(largeKey) || it.Value() != "whatever" {
+		it.Close()
 		t.Fatalf("Find(largeKey) = %q, %q; want %q, %q", it.Key(), it.Value(), largeKey, "whatever")
 	}
+	it.Close()
 
 	// insert with large value
 	if err := kv.Set("whatever", string(largeValue)); err != nil {

pkg/sorted/sqlkv/sqlkv.go

@@ -177,6 +177,9 @@ func (kv *KeyValue) Close() error { return kv.DB.Close() }
 func (kv *KeyValue) Find(start, end string) sorted.Iterator {
 	if kv.Serial {
 		kv.mu.Lock()
+		// TODO(mpl): looks like sqlite considers the db locked until we've closed
+		// the iterator, so we can't do anything else until then. We should probably
+		// move that Unlock to the closing of the iterator. Investigating.
 		defer kv.mu.Unlock()
 	}
 	var rows *sql.Rows