fixup! Disallow colocating tables when collations don't match

Author: onurctirtir

src/backend/distributed/sql/udfs/fix_pre_citus14_colocation_group_collation_mismatches/14.0-1.sql

@@ -20,8 +20,12 @@ BEGIN
              JOIN pg_attribute pa
                ON pa.attrelid = pdp.logicalrelid
               AND pa.attname = column_to_column_name(pdp.logicalrelid, pdp.partkey)
-            -- ignore the table if its distribution column collation matches the collation saved for the colocation group
-            WHERE pdc.distributioncolumncollation != pa.attcollation
+                  -- column_to_column_name() returns NULL if partkey is NULL, so we're already
+                  -- implicitly ignoring the tables that don't have a distribution column, such
+                  -- as reference tables, but let's still explicitly discard such tables below.
+            WHERE pdp.partkey IS NOT NULL
+                  -- ignore the table if its distribution column collation matches the collation saved for the colocation group
+              AND pdc.distributioncolumncollation != pa.attcollation
        )
        SELECT
            colocationid,
@@ -58,15 +62,15 @@ BEGIN
                     -- but this won't be super easy. Plus, even if we had such a colocation group, the user
                     -- was anyways okay with having this in a different colocation group in the first place.
 
-                    RAISE DEBUG 'Moving out table with id % to a new colocation group', v_table_to_move_out;
+                    RAISE DEBUG 'Moving out table with oid % to a new colocation group', v_table_to_move_out;
                     PERFORM update_distributed_table_colocation(v_table_to_move_out, colocate_with => 'none');
 
                     -- save the first table to colocate the rest of the tables with it
                     v_first_table := v_table_to_move_out;
                 ELSE
                     -- Move the rest of the tables to colocate with the first table.
 
-                    RAISE DEBUG 'Moving out table with id % to colocate with table with id %', v_table_to_move_out, v_first_table;
+                    RAISE DEBUG 'Moving out table with oid % to colocate with table with oid %', v_table_to_move_out, v_first_table;
                     PERFORM update_distributed_table_colocation(v_table_to_move_out, colocate_with => v_first_table::regclass::text);
                 END IF;
             END LOOP;

src/backend/distributed/sql/udfs/fix_pre_citus14_colocation_group_collation_mismatches/latest.sql

@@ -205,7 +205,6 @@ select count(*) = 2 as colocationids_different from (
 		and pg_class.relname in ('test_d_tbl_1', 'test_d_tbl_2')
 ) q;
 
-
 DROP TABLE test_d_tbl_1, test_d_tbl_2;
 
 create table test_b_tbl_1(text_col text collate "C" unique);