- * This function commits all DB changes as needed before
- * the user can receive a response (in case commit fails)
+ * This function commits all DB and session changes as needed *before* the
+ * client can receive a response (in case DB commit fails) and thus also before
+ * the response can trigger a subsequent related request by the client
+ *
+ * If there is a significant amount of content to flush, it can be done in $postCommitWork