sync_utils.py 文件源码

def _dequeuing_delete_rmcb_records(cursor, transfersession_id):
    # delete all RMCBs which are a reverse FF (store version newer than buffer version)
    delete_rmcb_records = """DELETE FROM {rmcb}
                             WHERE model_uuid IN
                             (SELECT rmcb.model_uuid FROM {store} as store, {buffer} as buffer, {rmc} as rmc, {rmcb} as rmcb
                             /*Scope to a single record*/
                             WHERE store.id = buffer.model_uuid
                             AND  store.id = rmc.store_model_id
                             AND  store.id = rmcb.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 rmcb.transfer_session_id = '{transfer_session_id}'
                             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_rmcb_records)