Re: timestamp of the last replayed transaction

On Tue, Nov 9, 2010 at 1:05 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Mon, Nov 8, 2010 at 6:00 AM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>> On Sat, Nov 6, 2010 at 9:58 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>>> This looks good, but how about adding:
>>>
>>> if (!RecoveryInProgress())
>>>    PG_RETURN_NULL();
>>>
>>> Otherwise, if we're in Hot Standby mode for a while and then enter
>>> normal running, wouldn't this still return a (stale) value?
>>
>> Yes, but isn't that (stale) value useful to check how far WAL records
>> have been replayed, *after failover*?
>
> Oh, OK.  I guess that makes sense.  One other question - should we say
> pg_last_xact_replay_timestamp() rather than
> pg_xact_last_replay_timestamp(), for consistency with
> pg_last_xlog_replay_location()?

Yeah, pg_last_xact_replay_timestamp was my first idea. But, for me
(with poor English),
that sounded to return the timestamp of when the last transaction has
been replayed in
the standby, rather than the timestamp of the last replayed
transaction (i.e., when the
last replayed transaction has been committed in the master). So I
didn't choose that name.

But, pg_last_xact_replay_timestamp is more intuitive for many people?
If so, let's change
the name.

Regards,

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