diff --git a/relayapi/storage/interface.go b/relayapi/storage/interface.go
index c754c21a3..f5f9a06e5 100644
--- a/relayapi/storage/interface.go
+++ b/relayapi/storage/interface.go
@@ -22,9 +22,26 @@ import (
 )
 
 type Database interface {
+	// Adds a new transaction to the queue json table.
+	// Adding a duplicate transaction will result in a new row being added and a new unique nid.
+	// return: unique nid representing this entry.
 	StoreTransaction(ctx context.Context, txn gomatrixserverlib.Transaction) (*receipt.Receipt, error)
+
+	// Adds a new transaction_id: server_name mapping with associated json table nid to the queue
+	// entry table for each provided destination.
 	AssociateTransactionWithDestinations(ctx context.Context, destinations map[gomatrixserverlib.UserID]struct{}, transactionID gomatrixserverlib.TransactionID, dbReceipt *receipt.Receipt) error
+
+	// Removes every server_name: receipt pair provided from the queue entries table.
+	// Will then remove every entry for each receipt provided from the queue json table.
+	// If any of the entries don't exist in either table, nothing will happen for that entry and
+	// an error will not be generated.
 	CleanTransactions(ctx context.Context, userID gomatrixserverlib.UserID, receipts []*receipt.Receipt) error
+
+	// Gets the oldest transaction for the provided server_name.
+	// If no transactions exist, returns nil and no error.
 	GetTransaction(ctx context.Context, userID gomatrixserverlib.UserID) (*gomatrixserverlib.Transaction, *receipt.Receipt, error)
+
+	// Gets the number of transactions being stored for the provided server_name.
+	// If the server doesn't exist in the database then 0 is returned with no error.
 	GetTransactionCount(ctx context.Context, userID gomatrixserverlib.UserID) (int64, error)
 }
diff --git a/relayapi/storage/shared/storage.go b/relayapi/storage/shared/storage.go
index 040ae0c06..03f9317dd 100644
--- a/relayapi/storage/shared/storage.go
+++ b/relayapi/storage/shared/storage.go
@@ -98,6 +98,15 @@ func (d *Database) CleanTransactions(
 
 	err := d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
 		deleteEntryErr := d.RelayQueue.DeleteQueueEntries(ctx, txn, userID.Domain(), nids)
+		// TODO : If there are still queue entries for any of these nids for other destinations
+		// then we shouldn't delete the json entries.
+		// But this can't happen with the current api design.
+		// There will only ever be one server entry for each nid since each call to send_relay
+		// only accepts a single server name and inside there we create a new json entry.
+		// So for multiple destinations we would call send_relay multiple times and have multiple
+		// json entries of the same transaction.
+		//
+		// TLDR; this works as expected right now but can easily be optimized in the future.
 		deleteJSONErr := d.RelayQueueJSON.DeleteQueueJSON(ctx, txn, nids)
 
 		if deleteEntryErr != nil {