RE: Disallow UPDATE/DELETE on table with unpublished generated column as REPLICA IDENTITY - Mailing list pgsql-hackers

On Saturday, November 16, 2024 2:41 AM Shlok Kyal <shlok.kyal.oss@gmail.com> wrote:
> 
> >
> Thanks for providing the comments. I have fixed all the comments and attached
> the updated patch.

Thanks for the patch. I have one comment for the following codes:

+        /*
+         * Bitmap of published columns when publish_generated_columns is
+         * 'false' and no column list is specified.
+         */
+        columns = pub_form_cols_map(relation, false);
+
+        /*
+         * Attnums in the bitmap returned by RelationGetIndexAttrBitmap are
+         * offset (to handle system columns the usual way), while column list
+         * does not use offset, so we can't do bms_is_subset(). Instead, we
+         * have to loop over the idattrs and check all of them are in the
+         * list.
+         */
+        x = -1;
+        while ((x = bms_next_member(idattrs, x)) >= 0)
+        {
...
+        }


It doesn't seem necessary to build a bitmap and then iterator the replica
identity bitmap. Instead, we can efficiently traverse the columns as follows:

for (int i = 0; i < desc->natts; i++)
{
    Form_pg_attribute att = TupleDescAttr(desc, i);

    if (!att->attisdropped && att->attgenerated &&
        bms_is_member(att->attnum - FirstLowInvalidHeapAttributeNumber,
        idattrs))
    {
        result = true;
        break;
    }
}

Best Regards,
Hou zj