Subject Re: [firebird-support] Re: Firebird performance vs PostgreSQL
Author Ertan Küçükoğlu
Hello Dmitry,

Thank you for your time. I just provided a reproducible sample. I'm not trying to make fine tuning to FirebirdSQL or PostgreSQL.

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?

I'm not experienced with both database systems internals. I'm not very good at reading query plans be that FirebirdSQL or PostgreSQL. So, it maybe plain reading plan that puts FirebirdSQL slower as you indicated.

Thanks & regards,
Ertan Küçükoğlu

Sent from my iPhone

On 29 Sep 2017, at 08:34, Dmitry Yemanov dimitr@... [firebird-support] <> wrote:


29.09.2017 01:08, Ertan Küçükoğlu wrote:

Answers can be found in the plans:


This join plan is terrible for FB. Are KAYNAGAGORE and SEBEBEGORE
indexed? They seem not.

> Merge Left Join (cost=6600.19..6610.98 rows=560 width=340)

FB cannot perform merge- or hash-join for outer joins (yet). When
important indices are missing, this becomes a problem.