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Re: Looking for advice where to start looking at a slow query case


On Wed, 27 Jul 2022, 00:11 , <ngtech1ltd@xxxxxxxxx> wrote:

> Hey Gordan,
> Got you..
> I actually have a script that can translate the relevant tables for the
> benchmark test In mind but have yet to sit on it.
> I really do not have any intention of replacing the DB but merely try to
> understand if this similar issue in the query optimizer
> present in most of the popular DB systems.
> I do assume that Oracle DB do not have an issue since I have seen it does
> a much more complex queries on a very large data sets
> pretty easily, however there is a difference between what I believe to
> what I know when I am trying to state that  there is a bug in
> any DB what so ever and whatever the depth of this bug.

On an extensive enough test - you will find optimizer anomalies like this
in all RDBMS-es. They won't be in the same place (same combination of
queries and data), but there is a reason why most of them have index
hinting features (and in those that don't, it is a common feature request).
No optimizer is ever perfect, it's all based in heuristics to make educated