Re: Why copy_relation_data only use wal whenWALarchivingis enabled

Поиск
Список
Период
Сортировка
От Heikki Linnakangas
Тема Re: Why copy_relation_data only use wal whenWALarchivingis enabled
Дата
Msg-id 4717273E.9000300@enterprisedb.com
обсуждение исходный текст
Ответ на Re: Why copy_relation_data only use wal whenWALarchivingis enabled  ("Jacky Leng" <lengjianquan@163.com>)
Список pgsql-hackers
Jacky Leng wrote:
>> I tend to agree that truncating the file, and extending the fsync
>> request mechanism to actually delete it after the next checkpoint,
>> is the most reasonable route to a fix.
> 
> How about just allowing to use wal even WAL archiving is disabled?
> It seems that recovery of "XLOG_HEAP_NEWPAGE" record will do the
> right thing for us, look at "heap_xlog_newpage": XLogReadBuffer
> with init=true will extend the block rightly and rebuild it rightly.
> 
> Someone may say that it's not worth recording xlog for operations
> such as copy_relation_data, but these operations shouldn't happen
> frequently. 

Always using WAL would fix the problem, but it's a big performance hit.
WAL-logging doubles the amount of write I/O required.

--  Heikki Linnakangas EnterpriseDB   http://www.enterprisedb.com


В списке pgsql-hackers по дате отправления:

Предыдущее
От: "Jacky Leng"
Дата:
Сообщение: Re: Why copy_relation_data only use wal when WALarchiving is enabled
Следующее
От: Gregory Stark
Дата:
Сообщение: Re: ts_rewrite aggregate API seems mighty ugly