Re: read-only database
От | Simon Riggs |
---|---|
Тема | Re: read-only database |
Дата | |
Msg-id | 1111050830.11750.230.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: read-only database (Satoshi Nagayasu <nagayasus@nttdata.co.jp>) |
Список | pgsql-hackers |
On Thu, 2005-03-17 at 12:40 +0900, Satoshi Nagayasu wrote: > Tom Lane wrote: > >>I saw Oracle's reference manual, and found ALTER DATABASE OPEN READ ONLY command > >>to make a stand-by database. > > > > Perhaps, but that's *not* what the TODO item is about. > > I see. > > Thanks for comments. The Oracle ALTER DATABASE command is part of the multi-step process to mount an Oracle database into a running instance. It isn't something that you can dip in and out of when you choose, as far as I am aware: you can only run it on a warm standby database that is receiving logs shipped from another database. i.e. Oracle warm-standby databases have 3 run states (ok, more, but...) 1. warm standby 2. read-only 3. fully-operational You can switch between 1 and 2 and back again, but once you go to 3 then you cannot switch back. What Tom just proposed about having an additional run-state between running-recovery and fully-operational is essentially the same thing. Tom's overall strategy would be workable in PostgreSQL terms, with some work and would provide similar functionality to Oracle. Having said that, I believe we're not close to making that work just yet - its a good end goal because there may be choices along the way that may need to consider the longer term goal. Best Regards, Simon Riggs
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