rdbms: add transaction comment to IDatabase::masterPosWait()

Change-Id: I95aa3b678b76cd06439d1feaba7f09a9c13f8931

diff --git a/includes/libs/rdbms/database/IDatabase.php b/includes/libs/rdbms/database/IDatabase.php
index 1973322..6d78dfc 100644 (file)
--- a/includes/libs/rdbms/database/IDatabase.php
+++ b/includes/libs/rdbms/database/IDatabase.php
@@ -1478,6 +1478,10 @@ interface IDatabase {
        /**
         * Wait for the replica DB to catch up to a given master position
         *
+        * Note that this does not start any new transactions. If any existing transaction
+        * is flushed, and this is called, then queries will reflect the point the DB was synced
+        * up to (on success) without interference from REPEATABLE-READ snapshots.
+        *
         * @param DBMasterPos $pos
         * @param int $timeout The maximum number of seconds to wait for synchronisation
         * @return int|null Zero if the replica DB was past that position already,