Subject Re: Firebird performance vs PostgreSQL
Author Dmitry Yemanov
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.