Em 26 de fev de 2016 4:44 PM, "joe meiring" <josephmeir...@gmail.com> escreveu: > > The same query for parameters is rather slow and does NOT use the index: > > EXPLAIN ANALYZE > select * > from parameter > where exists ( > select 1 from datavalue > where datavalue.parameter_id = parameter.id limit 1 > ); >
Please, could you execute both queries without the LIMIT 1 and show us the plans? LIMIT in the inner query is like a fence and it caps some optimizations available for EXISTS, you'd better avoid it and see if you get a proper semi-join plan then. Regards.
