I don't know how to give the planner more accurate info ...
Could you try to materialize the e.name subquery in another table. As in
create table func_var_name_for_tpl_15 as select e.name from functionalvariables e , usertemplatevariable ut where e.usertemplatevar_id=ut.id and ut.usertempl_id=15 ;
Then analyse that table Then try the rewritten query:
with filtered_s as ( select s.attvalue from functionalvarattributes s , tags t , variableattributetypes vat where t.id=s.tag_id and t.status!='Internal' and vat.fieldtype in ('DBF_INLINK','DBF_OUTLINK','DBF_FWDLINK') and vat.id=s.atttype_id and split_part(split_part(s.attvalue,' ',1),'.',1) in ( select e.name from func_var_name_for_tpl_15 e ) ) select s.attvalue from filtered_s s except select s.attvalue from filtered_s s , usertemplvarattribute utva , usertemplatevariable utv where utv.id=utva.usertempvariable_fk and utv.usertempl_id=15 ;
Does it use the vat_funcvaratt_multi_idx index now ?
