Fix a wrong comment in load_file()

On Mon, Dec 23, 2024 at 10:58:49AM +0800, cca5507 wrote:

/* If the same shlib has previously been loaded, unload and reload it. */

But we currently don't support to unload a shlib.

  * This function loads a shlib file without looking up any particular
  * function in it.  If the same shlib has previously been loaded,
- * unload and reload it.
+ * we don't load it again.

Right. This comment is misleading.

-	/* Load the shared library */
+	/* Load the shared library, unless we already did */
 	(void) internal_load_library(fullname);

This comment is still true, though. internal_load_library() has some
logic to make sure that we don't load twice the same library on
repeated calls of the function as the file_list is checked.
--
Michael

Michael Paquier <michael@paquier.xyz> writes:

On Mon, Dec 23, 2024 at 10:58:49AM +0800, cca5507 wrote:
* This function loads a shlib file without looking up any particular
* function in it. If the same shlib has previously been loaded,
- * unload and reload it.
+ * we don't load it again.

Right. This comment is misleading.

I think it was once correct, decades ago. Obviously we missed
fixing it when we ripped out the unload functionality.

-	/* Load the shared library */
+	/* Load the shared library, unless we already did */

This comment is still true, though.

Seems like an improvement to me?

regards, tom lane

On Sun, Dec 22, 2024 at 10:50:47PM -0500, Tom Lane wrote:

Michael Paquier <michael@paquier.xyz> writes:

Right. This comment is misleading.

I think it was once correct, decades ago. Obviously we missed
fixing it when we ripped out the unload functionality.

This was recent enough, and easy to miss.

-	/* Load the shared library */
+	/* Load the shared library, unless we already did */

This comment is still true, though.

Seems like an improvement to me?

Fine by me.

While on it, I think that we should adjust all these ones too:
contrib/sepgsql/hooks.c: * Module load/unload callback
contrib/auto_explain/auto_explain.c:/* Saved hook values in case of
unload */
contrib/passwordcheck/passwordcheck.c:/* Saved hook value in case of
unload */
contrib/pg_stat_statements/pg_stat_statements.c:/* Saved hook values
in case of unload */

The saved hooks are not here to readjust the stack based on a reload,
just to make sure that the existing paths loaded are all taken. I
would just remove the "in case of unload" part for the last three, and
"unload" for the first one. Thoughts?
--
Michael

Michael Paquier <michael@paquier.xyz> writes:

While on it, I think that we should adjust all these ones too:
contrib/sepgsql/hooks.c: * Module load/unload callback
contrib/auto_explain/auto_explain.c:/* Saved hook values in case of
unload */
contrib/passwordcheck/passwordcheck.c:/* Saved hook value in case of
unload */
contrib/pg_stat_statements/pg_stat_statements.c:/* Saved hook values
in case of unload */

Check.

The saved hooks are not here to readjust the stack based on a reload,
just to make sure that the existing paths loaded are all taken. I
would just remove the "in case of unload" part for the last three, and
"unload" for the first one. Thoughts?

WFM

regards, tom lane

&gt; The saved hooks are not here to readjust the stack based on a reload,
&gt; just to make sure that the existing paths loaded are all taken.&nbsp; I
&gt; would just remove the "in case of unload" part for the last three, and
&gt; "unload" for the first one.&nbsp; Thoughts?

LGTM.

--
Regards,
ChangAo Chen

On Sun, Dec 22, 2024 at 11:15:31PM -0500, Tom Lane wrote:

WFM

Okay, done this way then, thanks.
--
Michael