Re: What's the best practice to compare the transaction with the checkpoint?

On 7/6/2020 10:09 AM, Jialun Zhang wrote:
> Thanks! But what I actually mean is how to do this in the backend
> source code. I think I could find a way to do this SELECT in backend.

What would be the advantage in that method?

>
> Thank you,
> Jialun Zhang
>
> Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at
> <mailto:laurenz(dot)albe(at)cybertec(dot)at>> 于2020年7月6日周一 上午4:09写道：
>
> On Sat, 2020-07-04 at 12:19 -0400, Jialun Zhang wrote:
> > I am trying to add code to determine whether the transaction is
> checkpointed or not.
> > So I think I need to compare the transaction ID with the
> checkpoint's and determine
> > whether it is older or not. Could anyone tell me what's the best
> practice of doing
> > this in Postgres? Is it done somewhere in the existing code?
>
> You could use
>
>    SELECT next_xid FROM pg_control_checkpoint();
>
> to get information about the last checkpoint.
>
> I refrain from asking what the point of the exercise is...
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>

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