Gunther wrote:
> > Bad choices are almost always caused by bad estimates.
> > Granted, there is no way that estimates can ever be perfect.
> > ...
> > Looking deeper, I would say that wrongly chosen nested loop joins
> > often come from an underestimate that is close to zero.
> > PostgreSQL already
Thanks you for your thoughtful reply, Laurenz (funny that the people
interested in this topic are named Laurent and Laurenz :)
PostgreSQL doesn't have a way to tell if a query is an OLAP query
running against a star schema or a regular OLTP query, it will treat
both in the same fashion.
right,
Thanks for your support Laurent.
I have an idea on one thing you said:
Just adding to your voice. I recently experienced the same issue with a complex
multi-table view, including pivots, and was surprised to see all the nested
loops everywhere
and here is the clue for me:
in spite of indice
Gunther wrote:
> But there
> is one thing that keeps bothering me both with Oracle and PgSQL. And
> that is the preference for Nested Loops.
[...]
> But the issue is bulk searches, reports, and any analytic queries
> scenarios. In those queries Nested Loops are almost always a bad choice,
> e
> -Original Message-
> From: pgsql-performance-ow...@postgresql.org [mailto:pgsql-performance-
> ow...@postgresql.org] On Behalf Of Gunther
> Sent: Wednesday, November 01, 2017 20:29
> To: pgsql-performance@postgresql.org
> Subject: [PERFORM] OLAP/reporting queries fall
Hi, this is Gunther, have been with PgSQL for decades, on an off this
list. Haven't been on for a long time making my way just fine. But there
is one thing that keeps bothering me both with Oracle and PgSQL. And
that is the preference for Nested Loops.
Over the years the archives have question
