SQL error code = -901.
feature is not supported in dialect 1.

create table test(id bigint, fx int, fs smallint);
commit;
set sqlda_display;
set planonly;

select 
         count( id ) cnt_agg
        ,sum( id ) sum_agg_n64
        ,sum( fx ) sum_agg_n32
        ,sum( fs ) sum_agg_n16
from test;

INPUT  SQLDA version: 1 sqln: 10 sqld: 0

PLAN (TEST NATURAL)

OUTPUT SQLDA version: 1 sqln: 20 sqld: 4
01: sqltype: 496 LONG	  		 sqlscale: 0 sqlsubtype: 0  sqllen: 4 
  :  name: (0)  alias: (7)CNT_AGG
  : table: (0)  owner: (0)
02: sqltype: 581 INT64	 Nullable sqlscale: 0 sqlsubtype: 0 sqllen: 8
  :  name: (0)  alias: (11)SUM_AGG_N64
  : table: (0)  owner: (0)
03: sqltype: 581 INT64	 Nullable sqlscale: 0 sqlsubtype: 0 sqllen: 8
  :  name: (0)  alias: (11)SUM_AGG_N32
  : table: (0)  owner: (0)
04: sqltype: 581 INT64	 Nullable sqlscale: 0 sqlsubtype: 0 sqllen: 8
  :  name: (0)  alias: (11)SUM_AGG_N16
  : table: (0)  owner: (0)

-- page_size = 8K
SQL> recreate table test(x varchar(339) character set utf8 unique collate unicode_ci_ai); rollback;
SQL> recreate table test(x varchar(340) character set utf8 unique collate unicode_ci_ai); rollback;
Statement failed, SQLSTATE = 42000
unsuccessful metadata update
-key size exceeds implementation restriction for index "RDB$1"

-- page_size = 16K
SQL> recreate table test(x varchar(681) character set utf8 unique collate unicode_ci_ai); rollback;
SQL> recreate table test(x varchar(682) character set utf8 unique collate unicode_ci_ai); rollback;
Statement failed, SQLSTATE = 42000
unsuccessful metadata update
-key size exceeds implementation restriction for index "RDB$5"

max_key_length = floor( (page_size / 4 - 9) / N )