| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Markus Wanner <markus(at)bluegap(dot)ch> |
| Cc: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Synchronous Log Shipping Replication |
| Date: | 2008-09-08 23:10:40 |
| Message-ID: | 200809082310.m88NAel28205@momjian.us |
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| Thread: | |
| Lists: | pgsql-hackers |
Markus Wanner wrote:
> Hi,
>
> Bruce Momjian wrote:
> > Backends would
> > update a shared memory variable specifying how far they want the wal
> > streamer to advance and send a signal to the wal streamer if necessary.
> > Backends would monitor another shared memory variable that specifies how
> > far the wal streamer has advanced.
>
> That sounds like WAL needs to be written to disk, before it can be sent
> to the standby. Except maybe with some sort of mmap'ing the WAL.
Well, WAL is either on disk or in the wal_buffers in shared memory ---
in either case, a WAL streamer can get to it.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
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