Re: Logging WAL when updating hintbit

On Tue, Dec 3, 2013 at 12:02 PM, Michael Paquier
<michael.paquier@gmail.com> wrote:
> On Tue, Dec 3, 2013 at 11:57 AM, Michael Paquier
> <michael.paquier@gmail.com> wrote:
>> On Tue, Dec 3, 2013 at 1:08 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>>> Forcing it to be done only an initdb-time is excessive.  I think you
>>> can just make it PGC_POSTMASTER and have it participate in the
>>> XLOG_PARAMETER_CHANGE mechanism.  pg_rewind can check that it's set in
>>> the control file before agreeing to rewind.

Yep, I will modify it.

>> Indeed, I forgot this code path. Completing XLogReportParameters for
>> saving the state and xlog_redo for replay would be enough.
> Wait a minute, I retract this argument. By using this method a master
> server would be able to produce WAL files with inconsistent hint bit
> data when they are replayed if log_hint_bits is changed after a
> restart of the master.

How case does it occur?
I think pg_rewind can disagree to rewind if log_hint_bits is changed to 'OFF'.
Is this not enough?


Regards,

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Sawada Masahiko