Introduction

For the moment, the only engines that fully support encryption are XtraDB and InnoDB. The Aria storage engine also supports encryption, but only for temporary tables.

MariaDB supports 2 different way to encrypt data in InnoDB/XtraDB:

1. Specified table encryption: Only tables which you create with PAGE_ENCRYPTION=1 are encrypted. This feature was created by eperi.
2. Tablespace encryption: Everything is encrypted (including log files). This feature was created by Google and is based on their MySQL branch.

InnoDB Specified Table Encryption

Specified Table encryption means that you choose which tables to encrypt. This allows you to balance security with speed. To use table encryption, you have …

If you use Percona Server 5.5 and you have configured it to use multiple buffer pool instances than sooner or later you’ll see the following lines on the server’s error log and chances are you’ll be worried about them:

InnoDB: detected cycle in LRU for buffer pool 5, skipping to next buffer pool.
InnoDB: detected cycle in LRU for buffer pool 3, skipping to next buffer pool.
InnoDB: detected cycle in LRU for buffer pool 7, skipping to next buffer pool.

Worry not as this is mostly harmless. It’s becoming a February tradition for me (Fernando) to face a question about this subject (ok, it’s maybe a coincidence) and this time I’ve teamed up with my dear colleague and software engineer George Lorch to provide you the most complete blog post ever published on this topic … (with a belated thank you! to Ernie Souhrada, with whom I’ve also discussed this same …

During the process of reviewing our server defaults for MySQL 5.7, we thought that it might be better to change the default transaction isolation level from REPEATABLE-READ to READ-COMMITTED (the default for PostgreSQL, Oracle, and SQL Server). After some benchmarking, however, it seems that we should stick with REPEATABLE-READ as the default for now.

It’s very easy to modify the default isolation level, however, and it can even be done at the SESSION level. For the most optimal performance you can change the transaction isolation level dynamically in your SESSION according …

default_tmp_storage_engine variable was introduced in 5.6.3, allowing the configuration of the default engine for temporary tables. This seems to be in the direction, as I commented before, of making MyISAM an optional engine. In 5.7, a separate tablespace is being created to hold those tables in order to reduce its performance penalty (those tables do not need to be redone if the server crashes, so extra writes are avoided).

However, I have seen many people assuming that because default_tmp_storage_engine has the value “InnoDB”, all temporary tables are created in InnoDB format in 5.6. This is not true: first, because implicit temporary tables are still being created in memory using …

MySQL’s innodb_file_per_table is a wonderful thing – most of the time. Having every table use its own .ibd file allows you to easily reclaim space when dropping or truncating tables. But in some use cases, it may cause significant performance issues.

Many of you in the audience are responsible for running automated tests on your codebase before deploying to production. If you are, then one of your goals is having tests run as quickly as possible so you can run them as frequently as possible. Often times you can change specific settings in your test environment that don’t affect the outcome of the test, but do improve throughput. This post discusses how innodb_file_per_table is one of those settings.

I recently spoke with a customer whose use case involved creating hundreds of tables on up to 16 schemas …

MySQL’s default storage engine as of version 5.5 is InnoDB. InnoDB maintains a storage area called the buffer pool for caching data and indexes in memory. By keeping the frequently-accessed data in memory, related searches are retrieved much faster than reading from disk.

When you stop or restart MySQL, you lose the cached data stored in the buffer pool. There is a feature in MySQL 5.6 which allows you to dump the contents of the buffer pool before you shutdown the mysqld process. Then, when you start mysqld again, you can reload the contents of the buffer pool back into memory. You may also …

Within the MySQL data directory, the InnoDB storage engine creates two types of files — the data files and the redo log files. Each data file (or ibd file) belongs to exactly one tablespace. Each tablespace is given a unique identifier called the space_id. One tablespace can have 1 or more data files. If a tablespace has more than one data file, then the data files have a specific order or sequence. The data files can be thought of as being concatenated to each other in that specific order.

The data file is made up of a series of equal sized pages. Each page in the data file is given a unique number identifier called the page number (page_no). The first page of the first ibd file is given the page_no of 0. The page number of the first page of the second ibd file of the tablespace is …

Many of you have already heard about NoSQL databases and one of the the most used tool is Memcached, where you add a cache layer between the application and database. Since MySQL version 5.6, a new plugin is available to do the integration between MySQL and Memcached. On this article, we will learn how to install it on linux, and some basic configurations of it.

Pre-requirements:
Install libevent

Installation:
To install memcached support we will need to create a few tables responsible for MySQL and memcached integration. MySQL already includes the file which creates those tables (innodb_memcached_config.sql), you can find this file in a sub folder of your basedir. To discover where is your basedir, run the bellow command:

mysql> SHOW VARIABLES LIKE 'basedir';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| basedir       | /usr  | …

For months when speaking with customers I have been positioning Percona Cloud Tools (PCT) as a valuable tool for the DBA/Developer/SysAdmin but only recently have I truly been able to harness the data and make a technical recommendation to a customer that I feel would have been very difficult to accomplish otherwise.

Let me provide some background: I was tasked with performing a Performance Audit for one of our customers (Performance Audits are extremely popular as they allow you to have a MySQL Expert confirm or reveal challenges within your MySQL environment and make your database run faster!) and as part of our …

A few days ago I wrote about MySQL performance implications of InnoDB isolation modes and I touched briefly upon the bizarre performance regression I found with InnoDB handling a large amount of versions for a single row. Today I wanted to look a bit deeper into the problem, which I also filed as a bug.

First I validated in which conditions the problem happens. It seems to happen only in REPEATABLE-READ isolation mode and only in case there is some hot rows which get many row versions during a benchmark run. For example the problem does NOT happen if I run sysbench with “uniform” distribution.

In terms of concurrent selects it also seems to require some very special conditions – you need to have the connection to let some …