Subject: Re: proposal - get_extension_version function

From: Pavel Stehule <[email-masked]>
Date: Wed, 8 Mar 2023 20:19:15 +0100

st 8. 3. 2023 v 19:49 odesílatel Tom Lane <[email-masked]> napsal:

> Pavel Stehule <[email-masked]> writes:
> > I try to write a safeguard check that ensures the expected extension
> > version for an extension library.
>
> This is a bad idea.  How will you do extension upgrades, if the new .so
> won't run till you apply the extension upgrade script but the old .so
> malfunctions as soon as you do?  You need to make the C code as forgiving
> as possible, not as unforgiving as possible.
>

This method doesn't break  updates. It allows any registration, just
doesn't allow execution with unsynced SQL API.

>
> If you have C-level ABI changes you need to make, the usual fix is to
> include some sort of version number in the C name of each individual
> function you've changed, so that calls made with the old or the new SQL
> definition will be routed to the right place.  There are multiple
> examples of this in contrib/.
>

In my extensions like plpgsql_check I don't want to promise compatible ABI.
I support PostgreSQL 10 .. 16, and I really don't try to multiply code for
any historic input/output.

>                         regards, tom lane