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Search Results for: sql query to count number of tables in database

Generating test data for MySQL tables

One of the common tasks requested by our support customers is to optimize slow queries. We normally ask for the table structure(s), the problematic query and sample data to be able to reproduce the problem …


MySQL server memory usage troubleshooting tips

There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a …


Designing one to many relations – MongoDB vs MySQL

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 …


SSL Performance Overhead in MySQL

NOTE: This is part 1 of what will be a two-part series on the performance implications of using in-flight data encryption. Some of you may recall my security webinar from back in mid-August; one of …


How to move the InnoDB log sequence number (LSN) forward

This post focuses on the problem of the InnoDB log sequence number being in the future. Preface: What is an InnoDB log sequence number? The Log sequence number (LSN) is an important database parameter used by …


Advanced MySQL Query Tuning: Webinar followup Q&A

Thanks to all who attended my “MySQL Query Tuning” webinar on July 24.  If you missed it, you can you can download the slides and also watch the recorded video. Thank you for the excellent …


Schema Design in MongoDB vs Schema Design in MySQL

For people used to relational databases and doing MySQL database design, using NoSQL solutions such as MongoDB brings interesting challenges. One of them is schema design: while in the relational world, normalization is a good …


Schema changes – what’s new in MySQL 5.6?

Among many of the improvements you can enjoy in MySQL 5.6, there is one that addresses a huge operational problem that most DBAs and System Administrators encounter in their life: schema changes. While it is …


More on MySQL transaction descriptors optimization

Since my first post on MySQL transaction descriptors optimization introduced in Percona Server 5.5.30-30.2 and a followup by Dimitri Kravchuk, we have received a large number of questions on why the benchmark results in both …


MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

So far most of the benchmarks posted about MySQL 5.6 use the sysbench OLTP workload.  I wanted to test a set of queries which, unlike sysbench, utilize joins.  I also wanted an easily reproducible set …