Re: [PATCH] Patch to compute Max LSN of Data Pages

On Monday, November 12, 2012 9:56 PM Alvaro Herrera wrote:
Robert Haas escribió:
> On Tue, Jul 31, 2012 at 8:09 AM, Amit kapila <amit(dot)kapila(at)huawei(dot)com> wrote:

>> >> I think I can see all of those things being potentially useful. There
>> >> are a couple of pending patches that will revise the WAL format
>> >> slightly; not sure how much those are likely to interfere with any
>> >> development you might do on (2) in the meantime.
> >
>> > Based on above conclusion, I have prepared a patch which implements Option-1
>
>> I wonder if we shouldn't make this a separate utility, rather than
>> something that is part of pg_resetxlog. Anyone have a thought on that
>> topic?

> That thought did cross my mind too.

One of the reasons for keeping it with pg_resetxlog, is that this was proposed as a solution for scenario's where user's db has become corrupt and now he
want to start it. So to do it he can find the max LSN and set the same using pg_resetxlog, it will avoid the further corruption of database after it got started.
If we keep it a separate utility then user needs to first run this utility to find max LSN and then use pg_resetxlog to achieve the same. I don't see a big problem in that
but may be it would have been better if there are other usecases for it.

However it might be used for other purpose also which I am not able to think.

Do you have any particular reasons for having it a separate utility?

With Regards,
Amit Kapila.