In this blog, I’ll look at the impact of swapping on MySQL performance. 

It’s common sense that when you’re running MySQL (or really any other DBMS) you don’t want to see any I/O in your swap space. Scaling the cache size (using

innodb_buffer_pool_size

 in MySQL’s case) is standard practice to make sure there is enough free memory so swapping isn’t needed.   

But what if you make some mistake or miscalculation, and swapping happens? How much does it really impact performance? This is exactly what I set out to investigate.

My test system has the following:

• 32GB of physical memory
• OS (and swap space) on a (pretty old) Intel 520 SSD device
• Database stored on Intel 750 NVMe storage

To simulate a worst case scenario, I’m using Uniform Sysbench Workload:

sysbench …

In MySQL 8.0 our plan is to drastically improve support for utf8. While utf8 support itself dates back to MySQL 4.1, there exist some limitations. The “sushi = beer” problem in the title refers to Bug #76553. Sushi and beer don’t even go well together, at least not to my taste:-) I will use this bug as an example to explain issues with utf8 collations in the past and our plans for utf8 support going forward.…

On February 3rd, just before Fosdem and the MySQL & Friends Devroom, MySQL’s Community Team is organizing the pre-Fosdem MySQL Day.

Today’s highlighted sessions are the one of Øystein Grøvlen:

• MySQL 8.0: Common Table Expressions (CTEs)
• Using Optimizer Hints to Improve MySQL Query Performance

Øystein is Senior Principal Software Engineer in the MySQL group at Oracle, where he works on the MySQL Query Optimizer.  

Dr. Grøvlen has a PhD in Computer Science from the Norwegian University of Science and Technology.  Before joining the MySQL team, he was a contributor on the Apache Derby …

If you are using Percona XtraBackup with

xbcrypt

 to create encrypted backups, and are using versions older than 2.3.6 or 2.4.5, we advise that you upgrade Percona XtraBackup.

Note: this does not affect encryption …

From time to time we see in customer engagements that MySQL Master/Slave replication is set-up doing schema or table level replication filtering. This can be done either on Master or on Slave. If filtering is done on the Master (by the binlog_{do|ignore}_db settings), the binary log becomes incomplete and cannot be used for a proper Point-in-Time-Recovery. Therefore FromDual recommends AGAINST this approach.

The replication filtering rules vary depending on the binary log format (ROW and STATEMENT) See also: How Servers Evaluate Replication Filtering Rules.

For reasons of data consistency between Master and Slave FromDual recommends to use only the binary log format ROW. This is also stated in the …

As written yesterday, on February 3rd, just before Fosdem and the MySQL & Friends Devroom, MySQL’s Community Team is organizing the pre-Fosdem MySQL Day.

The second talk of this series is the session of Bernt Marius Johnsen: MySQL 8.0 & Unicode – What, why and how ?

Bernt is Senior QA Engineer in the MySQL Server Team. He’s working with QA in general but he’s also specialized in character sets and security issues. He also in charge of the development of  test tools automation.

MySQL 8.0 introduces a whole new set of Unicode collations based on Unicode 9.0 for the MySQL utf8mb4 character set. This comes in …

Fossasia 2017 will take place 17th – 19th March 2017 in Singapore.

Like previous edition, MySQL will sponsor this event. This year the organizers are looking for MySQL speakers. So if you are interested to speak about your favorite database and share your experience during Asia’s Premier Open Technology Event, please submit your talk using the following form: 2017.fossasia.org/speaker-registration

I know the deadline is over but they extended it a bit !

Last time we set up a connection from a PHP program to a MySQL server. This time we will progress a little further in that direction. QueryData is asked for from the MySQL server by using a query written in a language named Structured Query Language (SQL). Now that we have a connection open to the server, we can pass out request to the server. Manual LaborThe PHP Manual is wonderful 99% of time. If you take a peek at the page for mysqli::query there is a great example of a simple query. Many of learned to program by copying/pasting from books/manuals and this is a great us of the examples in the PHP manual. Except it may not work for you.

MySQL is usually case SeNsATiVe, so 'A' may not be the same thing as 'a'. But this is dependent to some extent on your operating …

The MySQL database workload is determined by the number of queries that it processes. There are several situations in which MySQL slowness can originate. The first possibility is if there is any queries that are not using proper indexing. When a query cannot make use of an index, the MySQL server has to use more resources and time to process that query. By monitoring queries, you have the ability to pinpoint SQL code that is the root cause of a slowdown.

Related resources  Become a MySQL DBA blog series - Using Explain to improve SQL Queries  Become a MySQL DBA blog series - Optimizer Hints for faster query execution …

The MySQL database workload is determined by the number of queries that it processes. There are several situations in which MySQL slowness can originate. The first possibility is if there is any queries that are not using proper indexing. When a query cannot make use of an index, the MySQL server has to use more resources and time to process that query. By monitoring queries, you have the ability to pinpoint SQL code that is the root cause of a slowdown.

Related resources  Become a MySQL DBA blog series - Using Explain to improve SQL Queries  Become a MySQL DBA blog series - Optimizer Hints for faster query execution …