We already discussed one to one relations in MongoDB, and the main conclusion was that you should design your collections according to the most frequent access pattern. With one to many relations, this is still valid, but other factors may come into play. Let’s look at a simple problem: we are a shop and we […]
Search Results for: inner join performance
Join me Wednesday, September 18 at 10 a.m. PDT for an hour-long webinar where I will introduce the basic concepts behind column store technology. The webinar’s title is: “Introduction to open source column stores.” What will be discussed? This webinar will talk about Infobright, LucidDB, MonetDB, Hadoop (Impala) and other column stores I will compare […]
This is the second part in a two-part series comparing Virident’s vCache to FlashCache. The first part was focused on usability and feature comparison; in this post, we’ll look at some sysbench test results. Disclosure: The research and testing conducted for this post were sponsored by Virident. First, some background information. All tests were conducted […]
While preparing the webinar I will deliver this Friday, I ran into a quite interesting (although not very impacting) optimizer issue: a “SELECT *” taking half the time to execute than the same “SELECT one_indexed_column” query in MySQL 5.6.10. This turned into a really nice exercise for checking the performance and inner workings of one […]
We’re told that foreign key constraints are the best way to enforce logical referential integrity (RI) in SQL, preventing rows from becoming orphaned. But then we learn that the enforcement of foreign keys incurs a significant performance overhead.1,2 MySQL allows us to set FOREIGN_KEY_CHECKS=0 to disable enforcement of RI when the overhead is too high. But […]
The much-anticipated ability to access MySQL data via a NoSQL solution has been realized. Using HandlerSocket, significant performance gains can be realized for certain workloads. Sound like something you are interested in? Join us for Percona Live London to hear Ryan Lowe, Percona’s Director of American Consulting speak on this subject. In Ryan’s session he […]
The new release of Maatkit has a useful feature in mk-index-usage to help you determine how indexes are used in more flexible ways. The default report just prints out ALTER statements for removing unused indexes, which is nice, but it’s often helpful to ask more sophisticated questions about index usage. I’ll use this blog’s queries […]
This is the third in a series on whatâ€™s seriously limiting MySQL in certain circumstances (links: part 1, 2). This post is about subqueries, which in some cases execute outside-in instead of inside-out as users expect.
About half a year have passed since me and Vadim have left MySQL to do MySQL Consulting on our own. Bunch of people have been wondering about our experiences so I thought it would be worth to share it here.
Whenever I see benchmark results I try to understand if it is technical benchmark – made by people seeking the truth or it is done by Marketing department to wash your brains. Watch out. Whenever you treat marketing benchmarks as technical ones, you make make wrong decision. Take a look at MySQL 5.0 Benchmarks Whitepaper […]