Table Functions And Join Cardinality Estimates
If you consider the usage of Table Functions then you should be aware of some limitations to the optimizer calculations, in particular when considering a join between a Table Function and other row...
View Article"Cost-free" joins - 1
Recently I came across some interesting edge cases regarding the costing of joins. They all have in common that they result in (at first sight) unexpected execution plans, but only some of them are...
View Article"Cost-free" joins - 2
In the previous post I've demonstrated an unexpected Nested Loop Join caused by an extreme data distribution. Although unexpected at first sight, the performance of the execution plan selected by the...
View Article[Oracle] SQL Execution Engine Part I - Join data by hashing alias Hash Joins
IntroductionWe already took a (tiny) closer look at the cost based optimizer in my first series called "DB Optimizer". So i decided to start another tiny series about the SQL execution engine, which...
View ArticleA tribute to Natural Join
By Franck Pachot. I know that lot of people are against the ANSI join syntax in Oracle. And this goes beyond the limits when talking about NATURAL JOIN. But I like them and use them quite often.read more
View ArticleChinar Aliyev's Blog
Chinar Aliyev has recently started to pick up on several of my blog posts regarding Parallel Execution and the corresponding new features introduced in Oracle 12c.It is good to see that obviously...
View ArticleBloom Filter Efficiency And Cardinality Estimates
I've recently came across an interesting observation I've not seen documented yet, so I'm publishing a simple example here to demonstrate the issue.In principle it looks like that the efficiency of...
View ArticleA tribute to Natural Join
By Franck Pachot. I know that lot of people are against the ANSI join syntax in Oracle. And this goes beyond the limits when talking about NATURAL JOIN. But I like them and use them quite often.read more
View ArticleA tribute to Natural Join
By Franck Pachot. I know that lot of people are against the ANSI join syntax in Oracle. And this goes beyond the limits when talking about NATURAL JOIN. But I like them and use them quite often.read more
View ArticleOracle 12c ā pre-built join index
By Franck Pachot. This post is part of a series of small examples of recent features. Iām running this in the Oracle 20c preview in the Oracle Cloud. I have created a few tables in the previous post...
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