Optimizer ODS 7.23

We have performance problems with the following statement (a.o.) SELECT f.ind_glob_db_access, cf.dml_action FROM functionx f, OUTER col_funcx cf WHERE f.sys_nm = cf.sys_nm AND f.func_cd = cf.func_cd AND f.sys_nm = "FAAIX" AND f.func_cd = "API_AFD_ST" AND cf.rt_nm ="AFDELING" and cf.col_nm IS NULL AND cf.dml_action = "I" Unique indexes are on functionx(sys_nm, func_cd) and col_funcx(sys_nm, rt_nm, col_nm, func_cd, dml_action) Duplicate index is on col_funcx(sys_nm, func_cd) Set explain gives an estimated cost of 2, using 2 index paths and a hash join If the OUTER is removed, set explain gives an estimated cost of 3, using 2 index paths ............ HOWEVER ............ The query without the OUTER is many times faster than the one with it. Possible causes: * the optimizer can't deal with OUTER joins * the optimizer can't deal with NULL restrictions on an index column System is ODS 7.23 on an NT server (2x PPro 200) Anyone got a hint? Thanx in advance Frido ------------------------------------------------------------------------ Frido van Orden FAA Partners BV Planetenbaan 117 3606 AK Maarssen The Netherlands Phone: +31-346-587076 Fax: +31-346-587086 Email: fridoo@faapartners.com ------------------------------------------------------------------------ -