Re: will PITR in 8.0 be usable for "hot spare"/"log shipping" type of replication - Mailing list pgsql-hackers

From Tom Lane
Subject Re: will PITR in 8.0 be usable for "hot spare"/"log shipping" type of replication
Date
Msg-id 5009.1092497386@sss.pgh.pa.us
Whole thread Raw
In response to Re: will PITR in 8.0 be usable for "hot spare"/"log shipping" type of replication  ("Simon@2ndquadrant.com" <simon@2ndquadrant.com>)
List pgsql-hackers
"Simon@2ndquadrant.com" <simon@2ndquadrant.com> writes:
>> Tom Lane wrote:
>> Right, also an area that needs thought.  Some other people opined that
>> they want the switchover to occur only on manual command.  I'd go with
>> that too if you have anything close to 24x7 availability of admins.
>> If you *must* have automatic switchover, what's the safest criterion?
>> Dunno, but let's think ...

> That's fairly straightforward.

> You use a recovery_command that sleeps when it discovers a full log file
> isn't available - i.e. it has requested the "last" or master-current WAL
> file. The program wakes when the decision/operator command to switchover is
> taken.

But you're glossing over the hard part, which is how to take that
decision (assuming that for some reason you can't afford to wait for
a human to make it).
        regards, tom lane


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