Re: RecordTransactionCommit() and SharedInvalidationMessages

On Wed, Aug 11, 2010 at 11:35 PM, Heikki Linnakangas
<heikki.linnakangas@enterprisedb.com> wrote:
> On 11/08/10 16:46, Robert Haas wrote:
>>
>> On Wed, Aug 11, 2010 at 1:17 AM, Fujii Masao<masao.fujii@gmail.com>
>>  wrote:
>>>
>>> On Tue, Aug 10, 2010 at 9:30 AM, Robert Haas<robertmhaas@gmail.com>
>>>  wrote:
>>>>
>>>> It appears to me that RecordTransactionCommit() only needs to WAL-log
>>>> shared invalidation messages when wal_level is hot_standby, but I
>>>> don't see a guard to prevent it from doing it in all cases.
>>>
>>> Perhaps right. During not hot standby, there is no backend which the
>>> startup process should send invalidation message to in the standby.
>>> So, ISTM we don't need to log invalidation message when wal_level is
>>> not hot_standby.
>>
>> The fix looks pretty simple (see attached), although I don't have any
>> clear idea how to test it.
>
> Should use XLogStandbyInfoActive() macro, for the sake of consistency.

And, RelcacheInitFileInval should be initialized with false just in case.

>> I guess the question is whether we should
>> back-patch this to 9.0.  It isn't technically necessary for
>> correctness, but the whole point of introducing the wal_level GUC was
>> to insulate people not running Hot Standby from possible bugs in the
>> Hot Standby code, as well as to avoid unnecessary WAL bloat, so on
>> balance I'm inclined to think we should go ahead and back-patch it.
>
> +1 for backpatching. Keeping the branches closer to each other makes
> backporting any future fixes easier too.

+1

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center