Re-add comments

message/store.go

@@ -98,6 +98,7 @@ func newCommonStore(db *sql.DB, queries storeQueries, batchSize int, batchTimeou
 }
 
 // AddMessage stores a message to the message cache synchronously, or queues it to be stored at a later date asynchronously.
+// The message is queued only if "batchSize" or "batchTimeout" are passed to the constructor.
 func (c *commonStore) AddMessage(m *model.Message) error {
 	if c.queue != nil {
 		c.queue.Enqueue(m)
@@ -376,6 +377,7 @@ func (c *commonStore) DeleteScheduledBySequenceID(topic, sequenceID string) ([]s
 		return nil, err
 	}
 	defer tx.Rollback()
+	// First, get the message IDs of scheduled messages to be deleted
 	rows, err := tx.Query(c.queries.selectScheduledMessageIDsBySeqID, topic, sequenceID)
 	if err != nil {
 		return nil, err
@@ -392,7 +394,8 @@ func (c *commonStore) DeleteScheduledBySequenceID(topic, sequenceID string) ([]s
 	if err := rows.Err(); err != nil {
 		return nil, err
 	}
-	rows.Close()
+	rows.Close() // Close rows before executing delete in same transaction
+	// Then delete the messages
 	if _, err := tx.Exec(c.queries.deleteScheduledBySequenceID, topic, sequenceID); err != nil {
 		return nil, err
 	}

message/store_sqlite.go

@@ -135,6 +135,11 @@ func NewNopStore() (Store, error) {
 }
 
 // createMemoryFilename creates a unique memory filename to use for the SQLite backend.
+// From mattn/go-sqlite3: "Each connection to ":memory:" opens a brand new in-memory
+// sql database, so if the stdlib's sql engine happens to open another connection and
+// you've only specified ":memory:", that connection will see a brand new database.
+// A workaround is to use "file::memory:?cache=shared" (or "file:foobar?mode=memory&cache=shared").
+// Every connection to this string will point to the same in-memory database."
 func createMemoryFilename() string {
 	return fmt.Sprintf("file:%s?mode=memory&cache=shared", util.RandomString(10))
 }