| From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
|---|---|
| To: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
| Cc: | Magnus Hagander <magnus(at)hagander(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Streaming replication on win32, still broken |
| Date: | 2010-02-18 07:38:15 |
| Message-ID: | 4B7CEE67.8010002@enterprisedb.com |
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| Lists: | pgsql-hackers |
Fujii Masao wrote:
> On Thu, Feb 18, 2010 at 5:28 AM, Heikki Linnakangas
> <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
>> If I'm reading the patch correctly, when wal_sync_method is 'open_sync',
>> walreceiver nevertheless opens the WAL file without the O_DIRECT flag.
>> When it later flushes it in XLogWalRcvFlush() by issue_xlog_fsync(),
>> issue_xlog_fsync() will do nothing because it assumes the write() synced
>> it already. So the data written isn't being forced to disk at all.
>
> When 'open_sync' is chosen, the WAL file is opened with O_SYNC or O_FSYNC
> flag. So I think that write() flushes the data to disk even if O_DIRECT
> flag is not given. Am I missing something?
Ah, ok, you're right.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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