Re: Import Statistics in postgres_fdw before resorting to sampling.

On Fri, May 1, 2026 at 3:04 AM Corey Huinker <corey.huinker@gmail.com> wrote:
> I've attached 2 different fixes.

Thanks for the patches!

> The first one swtiches to pg_mbcliplen+memcpy, which is probably overkill but better safe than sorry.

I noticed that RemoteAttributeMapping.remote_attname is used in
match_attrmap(), which assumes that it fully contains a remote
attribute's name, so I think this solution is actually unsafe.

> The second gets rid of the string buffers entirely, and instead frees the nested object.
>
> I have no preference between the two, though I suspect that the nested-free solution will be preferred by the community.

ISTM that the second solution is the right direction to go in.

+static void
+free_remattrmap(RemoteAttributeMapping *map, int len)
+{
+   if (!map)
+       return;
+
+   for (int i = 0; i < len; i++)
+   {
+       if (map[i].local_attname)
+           pfree(map[i].local_attname);
+       if (map[i].remote_attname)
+           pfree(map[i].remote_attname);
+   }

The if tests for local_attname/remote_attname should be assertions?

It took more time than expected to return to this issue.  My apologies for that.

Best regards,
Etsuro Fujita