Re: pg_receivewal starting position - Mailing list pgsql-hackers

From Ronan Dunklau
Subject Re: pg_receivewal starting position
Date
Msg-id 3162614.44csPzL39Z@aivenronan
Whole thread Raw
In response to Re: pg_receivewal starting position  (Michael Paquier <michael@paquier.xyz>)
Responses Re: pg_receivewal starting position  (Michael Paquier <michael@paquier.xyz>)
List pgsql-hackers
Le lundi 25 octobre 2021, 09:40:10 CEST Michael Paquier a écrit :
> On Mon, Oct 25, 2021 at 09:15:32AM +0200, Ronan Dunklau wrote:
> > Does it make sense though ? The NULL slot_name case handling is pretty
> > straight forward has it will be handled by string formatting, but in the
> > case of a null restart_lsn, we have no way of knowing if the command was
> > issued at all.
>
> If I am following your point, I don't think that it matters much here,
> and it seems useful to me to be able to pass NULL for both of them, so
> as one can check if the slot exists or not with an API designed this
> way.

You're right, but I'm afraid we would have to check the server version twice
in any case different from the basic pg_receivewal on (once in the function
itself, and one before calling it if we want a meaningful result). Maybe we
should move the version check outside the GetSlotInformation function to avoid
this, and let it fail with a syntax error when the server doesn't support it ?

--
Ronan Dunklau





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