Re: Log Apply Delay

On Fri, Sep 16, 2011 at 8:35 AM, hubert depesz lubaczewski
<depesz(at)depesz(dot)com> wrote:
> On Fri, Sep 16, 2011 at 08:02:31AM -0700, Ian Harding wrote:
>> Oracle has a configuration option for its version of hot standby
>> (DataGuard) that lets you specify a time based delay in applying logs.
>>  They get transferred right away, but changes in them are only applied
>> as they reach a certain age.  The idea is that if something horrible
>> happens on the master, you can keep it from propagating to one or more
>> of your standby databases (or keep from having to reinstate one in the
>> case of a failover)
>>
>> Anyway, Is there any plan to add a knob like that to the streaming
>> replication in Postgres?
>
> In streaming - no. But if you want delay, perhaps normal WAL-files based
> approach would be good enough? OmniPITR, for one, has a option to delay
> applying wal segments.
>

The file based approach is pretty close, unless the Bad Thing happens
right before a file gets transferred. This is not a super important
feature to me but It's a nice security blanket and almost takes the
place of a PITR plan including big file transfers of the data
directory at regular intervals.

- Ian