29.09.2017 09:50, Ertan Küçükoğlu wrote: > > Answer to your question is yes. KAYNAGAGORE and SEBEBEGORE are not > indexed. Please note that they're not indexed on PostgreSQL, too. > > Question remains as how PostgreSQL can cope with identical data only > with primary key indexes faster than FirebirdSQL?
PG can do sort/merge for outer joins, whilst FB cannot (it can only for inner joins). When there are no indices for the joined columns, this makes a huge difference. PG uses the fast sort/merge algorithm, FB uses the slow (only without indices!) nested loop algorithm because it cannot do any better. This is a known subject of improvement. Dmitry
