sync_utils.py 文件源码

def _dequeuing_delete_buffered_records(cursor, transfersession_id):
    # delete all buffer records which are a reverse FF (store version newer than buffer version)
    delete_buffered_records = """DELETE FROM {buffer}
                                 WHERE model_uuid in
                                 (SELECT buffer.model_uuid FROM {store} as store, {buffer} as buffer, {rmc} as rmc
                                 /*Scope to a single record*/
                                 WHERE store.id = buffer.model_uuid
                                 AND rmc.store_model_id = buffer.model_uuid
                                 /*Checks whether LSB of buffer or less is in RMC of store*/
                                 AND buffer.last_saved_instance = rmc.instance_id
                                 AND buffer.last_saved_counter <= rmc.counter
                                 AND buffer.transfer_session_id = '{transfer_session_id}')
                              """.format(buffer=Buffer._meta.db_table,
                                         store=Store._meta.db_table,
                                         rmc=RecordMaxCounter._meta.db_table,
                                         rmcb=RecordMaxCounterBuffer._meta.db_table,
                                         transfer_session_id=transfersession_id)
    cursor.execute(delete_buffered_records)