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Re: What's the best practice to compare the transaction with the checkpoint? - Mailing list pgsql-novice

From Jialun Zhang
Subject Re: What's the best practice to compare the transaction with the checkpoint?
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Msg-id CAMFL+JjnQE8NWP1vMxfzJXFyjCP-9yvA6ku6FkJAjTpRkOoyTg@mail.gmail.com
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In response to Re: What's the best practice to compare the transaction with the checkpoint?  (Laurenz Albe <laurenz.albe@cybertec.at>)
Responses Re: What's the best practice to compare the transaction with the checkpoint?  (Gerald Cheves <gcheves@verizon.net>)
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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.

Thank you,
Jialun Zhang

Laurenz Albe <laurenz.albe@cybertec.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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