I have written a new post on the MySQL blog about the hypergraph optimizer, which is now available in MySQL 9.7 Community Edition. The post gives a high-level technical overview of what is different from the classic join optimizer, why it c…
This blog post is inspired by Jesper's recent blog post on how the automatic update of InnoDB persistent statistics may never trigger if servers are restarted frequently. However, the matter is even worse! In this blog post I will show that…
This blog post is inspired by Jesper's recent blog post on how the automatic update of InnoDB persistent statistics may never trigger if servers are restarted frequently. However, the matter is even worse! In this blog post I will show that…
In my previous blog post, I discussed different ways to rewrite correlated scalar subqueries to improve performance. In this blog post, I will discuss how we can use window functions for a subset of these queries. Window functions was intro…
In my previous blog post, I discussed different ways to rewrite correlated scalar subqueries to improve performance. In this blog post, I will discuss how we can use window functions for a subset of these queries. Window functions was intro…
MySQL 8.0.24 introduces transformation of correlated scalar subqueries to derived tables. In my presentation in the MySQL devroom at FOSDEM earlier this year, I showed how we can manually rewrite such queries. The automatic transformation i…
MySQL 8.0.24 introduces transformation of correlated scalar subqueries to derived tables. In my presentation in the MySQL devroom at FOSDEM earlier this year, I showed how we can manually rewrite such queries. The automatic transformation i…
At Percona Live Online my colleague at Alibaba, Jim Tommaney, presented a study of hash join performance in MySQL and Marwho?iaDB. For some of the queries, the peformance characteristics for MySQL seemed a bit strange, and I decided to look…
At Percona Live Online my colleague at Alibaba, Jim Tommaney, presented a study of hash join performance in MySQL and Marwho?iaDB. For some of the queries, the peformance characteristics for MySQL seemed a bit strange, and I decided to look…
As presented at the Percona Live Conference in Austin in May, at Alibaba we are working on adding support for parallel query execution to POLARDB for MySQL. As discussed in the presentation, we observe that parallel range scans on secondary…
As presented at the Percona Live Conference in Austin in May, at Alibaba we are working on adding support for parallel query execution to POLARDB for MySQL. As discussed in the presentation, we observe that parallel range scans on secondary…
FOSDEM is coming up. I do not have a presentation in the MySQL and Friends devroom this year, but it reminded me that I had planned to post a follow-up to my presentation from last year. As part of the presentation, I showed how you can ins…