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Virident vCache vs. FlashCache: Part 2

May 17, 2013 By Ernie Souhrada 3 Comments

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 [...]

Filed Under: Benchmarks, Hardware and Storage, MySQL Tagged With: Benchmarks, Ernie Souhrada, FlashCache, MLC, PCIe, sysbench, vCache, Virident

Follow these basics when migrating to Percona XtraDB Cluster for MySQL

May 1, 2013 By Jervin Real 10 Comments

Galera/Percona XtraDB Cluster (PXC) for MySQL is a hot thing right now and some users jump right in without enough testing. Consequently, they’re more likely to either suffer failure or issues that prevent them from moving forward. If you are thinking of migrating your workload to Percona XtraDB Cluster, make sure to go through these [...]

Filed Under: Insight for DBAs, MySQL, Percona Software, XtraDB Cluster Tagged With: galera, Jervin Real, Percona XtraDB Cluster, pxc, replicating

InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

March 4, 2013 By Ernie Souhrada 7 Comments

This is part 2 in a 3 part series. In part 1, we took a quick look at some initial configuration of InnoDB full-text search and discovered a little bit of quirky behavior; here, we are going to run some queries and compare the result sets. Our hope is that the one of two things [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: Ernie Souhrada, FTS, FullText Search, InnoDB, MyISAM, MySQL 5.6

Dynamic row format for MEMORY tables

September 6, 2011 By Laurynas Biveinis 5 Comments

The latest Percona Server release has one new feature: now MEMORY tables can have BLOB and TEXT columns, and VARCHAR columns will not waste space due to implicit extension to CHAR.

Filed Under: MySQL, Percona Software

Aligning IO on a hard disk RAID – the Benchmarks

June 9, 2011 By Aurimas Mikalauskas 13 Comments

In the first part of this article I have showed how I align IO, now I want to share results of the benchmark that I have been running to see how much benefit can we get from a proper IO alignment on a 4-disk RAID1+0 with 64k stripe element. I haven’t been running any benchmarks [...]

Filed Under: MySQL

Paul McCullagh answers your questions about PBXT

November 20, 2009 By Morgan Tocker 2 Comments

Following on from our earlier announcement, Paul McCullagh has responded with the answers to your questions – as well as a few I gathered from other Percona folks, and attendees of OpenSQL Camp. Thank you Paul! Whatâ€™s the “ideal” use case for the PBXT engine, and how does it compare in performance? Â When would I [...]

Filed Under: Insight for Developers, MySQL Tagged With: Community, interview, MariaDB, paul mccullagh, PBXT, Storage Engine

How (not) to find unused indexes

October 16, 2009 By Morgan Tocker 2 Comments

I’ve seen a few people link to an INFORMATION_SCHEMA query to be able to find any indexes that have low cardinality, in an effort to find out what indexes should be removed.Â This method is flawed – here’s the first reason why:

CREATE TABLE `sales` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`customer_id` int(11) DEFAULT NULL,
`status` enum('archived','active') DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `status` (`status`)
) ENGINE=MyISAM AUTO_INCREMENT=65691 DEFAULT CHARSET=latin1;
mysql> SELECT count(*), status FROM sales GROUP by status;
+----------+---------+
| count(*) | statusÂ  |
+----------+---------+
|Â Â Â  65536 | archived |
|Â Â Â Â Â  154 | activeÂ  |
+----------+---------+
2 rows in set (0.17 sec)
mysql> EXPLAIN SELECT * FROM sales WHERE status='active'; # query 1
+----+-------------+-------+------+---------------+--------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | keyÂ Â Â  | key_len | refÂ Â  | rows | ExtraÂ Â Â Â Â Â  |
+----+-------------+-------+------+---------------+--------+---------+-------+------+-------------+
|Â  1 | SIMPLEÂ Â Â Â Â  | sales | refÂ  | statusÂ Â Â Â Â Â Â  | status | 2Â Â Â Â Â Â  | const |Â  196 | Using where |
+----+-------------+-------+------+---------------+--------+---------+-------+------+-------------+
1 row in set (0.06 sec)
mysql> EXPLAIN SELECT * FROM sales WHERE status='archived'; # query 2
+----+-------------+-------+------+---------------+------+---------+------+-------+-------------+
| id | select_type | table | type | possible_keys | keyÂ  | key_len | refÂ  | rowsÂ  | ExtraÂ Â Â Â Â Â  |
+----+-------------+-------+------+---------------+------+---------+------+-------+-------------+
|Â  1 | SIMPLEÂ Â Â Â Â  | sales | ALLÂ  | statusÂ Â Â Â Â Â Â  | NULL | NULLÂ Â Â  | NULL | 65690 | Using where |
+----+-------------+-------+------+---------------+------+---------+------+-------+-------------+
1 row in set (0.01 sec)

CREATE TABLE `sales` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`customer_id` int(11) DEFAULT NULL,

`status` enum('archived','active') DEFAULT NULL,

PRIMARY KEY (`id`),

KEY `status` (`status`)

) ENGINE=MyISAM AUTO_INCREMENT=65691 DEFAULT CHARSET=latin1;

mysql> SELECT count(*), status FROM sales GROUP by status;

+----------+---------+

| count(*) | statusÂ |

+----------+---------+

|Â Â Â 65536 | archived |

|Â Â Â Â Â 154 | activeÂ |

+----------+---------+

2 rows in set (0.17 sec)

mysql> EXPLAIN SELECT * FROM sales WHERE status='active'; # query 1

+----+-------------+-------+------+---------------+--------+---------+-------+------+-------------+

+----+-------------+-------+------+---------------+--------+---------+-------+------+-------------+

+----+-------------+-------+------+---------------+--------+---------+-------+------+-------------+

1 row in set (0.06 sec)

mysql> EXPLAIN SELECT * FROM sales WHERE status='archived'; # query 2

+----+-------------+-------+------+---------------+------+---------+------+-------+-------------+

+----+-------------+-------+------+---------------+------+---------+------+-------+-------------+

+----+-------------+-------+------+---------------+------+---------+------+-------+-------------+

1 row in set (0.01 sec)

The cardinality of status index is woeful, but provided that the application [...]

Filed Under: Insight for DBAs, MySQL Tagged With: explain, indexing, MySQL, Tips

How number of columns affects performance ?

September 28, 2009 By Peter Zaitsev 12 Comments

It is pretty understood the tables which have long rows tend to be slower than tables with short rows. I was interested to check if the row length is the only thing what matters or if number of columns we have to work with also have an important role. I was interested in peak row [...]

Filed Under: Benchmarks, Insight for Developers, MySQL Tagged With: InnoDB, MyISAM

High-Performance Click Analysis with MySQL

December 22, 2008 By Baron Schwartz 13 Comments

We have a lot of customers who do click analysis, site analytics, search engine marketing, online advertising, user behavior analysis, and many similar types of work.Â The first thing these have in common is that they’re generally some kind of loggable event. The next characteristic of a lot of these systems (real or planned) is [...]

Filed Under: Insight for Developers Tagged With: Ideas, Optimizer, Replication, Tips, XtraDB

Using Multiple Key Caches for MyISAM Scalability

November 26, 2008 By Peter Zaitsev 8 Comments

I have written before – MyISAM Does Not Scale, or it does quite well – two main things stopping you is table locks and global mutex on the KeyCache. Table Locks are not the issue for Read Only workload and write intensive workloads can be dealt with by using with many tables but Key Cache [...]

Filed Under: Insight for DBAs Tagged With: Production

Virident vCache vs. FlashCache: Part 2

Follow these basics when migrating to Percona XtraDB Cluster for MySQL

InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

Dynamic row format for MEMORY tables

Aligning IO on a hard disk RAID – the Benchmarks

Paul McCullagh answers your questions about PBXT

How (not) to find unused indexes

How number of columns affects performance ?

High-Performance Click Analysis with MySQL

Using Multiple Key Caches for MyISAM Scalability

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