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Deep dive into MySQL’s innochecksum tool

One of our Percona Support customers recently reported that Percona XtraBackup failed with a page corruption error on an InnoDB table. The customer thought it was a problem or bug in the Percona XtraBackup tool. After investigation we found that an InnoDB page was actually corrupted and a Percona XtraBackup tool caught the error as expected and hence the backup job failed.

I thought this would be an interesting topic and worthy of a blog post. In this article I will describe the innochecksum tool, when and how to use it and what are the possible fixes if an InnoDB table suffers from …

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PostgreSQL Auto IDs

PostgreSQL’s approach to automatic numbering is as simple as Oracle but different than MySQL, and Microsoft SQL Server. For example, you have a two-step process with Oracle, PostgreSQL, MySQL, and Microsoft SQL Server. First, you create an Oracle table with the GENERATED AS IDENTITY clause, a PostgreSQL table with the SERIAL data type, a MySQL table with the AUTO_INCREMENT clause, and a Microsoft SQL Server table with the IDENTITY(1,1) clause. Then, you need to write an INSERT statement for Oracle, MySQL, or Microsoft SQL Server like:

  1. Oracle’s INSERT statement excludes the auto-incrementing column from the list of columns or provides a NULL value in the VALUES-list. You can then assign the RETURNING INTO result from an INSERT statement to a session-level (bind) variable.
  2. MySQL’s …
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MySQL-5.7.6: Introducing Multi-source replication

On March 10, 2015, we released MySQL-5.7.6 and among many other things it includes multi-source replication which …

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Auto Generated Columns in MySQL 5.7: Two Indexes on one Column made easy

One of my customers wants to search for names in a table. But sometimes the search is case insensitive, next time search should be done case sensitive. The index on that column always is created with the collation of the column. And if you search with a different collation in mind, you end up with a full table scan. Here is an example:

The problem

 mysql> SHOW CREATE TABLE City\G  
 *************************** 1. row ***************************  
 Table: City  
 Create Table: CREATE TABLE `City` (  
 `ID` int(11) NOT NULL AUTO_INCREMENT,  
 `Name` char(35) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  
 `CountryCode` char(3) NOT NULL DEFAULT '',  
 `District` char(20) NOT NULL DEFAULT '',  
 `Population` int(11) NOT NULL DEFAULT '0',  
 PRIMARY KEY (`ID`),  
 KEY `CountryCode` (`CountryCode`),  
 KEY `Name` (`Name`),  
 ) ENGINE=InnoDB AUTO_INCREMENT=4080 DEFAULT CHARSET=latin1  
 1 row in set (0,00 sec)  

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Promise from PLUK 2014 finally fulfilled: Better Parallel Replication for MySQL

http://blog.booking.com/better_parallel_replication_for_mysql.html

Follow the link above to read my latest article on the Booking.com developer blog.  It is about MySQL Parallel Replication and Binlog Servers.

This fulfills my promise made at Percona Live London 2014 during my talk High Availability, Disaster Recovery and Extreme Read Scaling using Binlog Servers: I finally took the time to

Q&A: Multi-threaded Replication in MySQL 5.6 and MySQL 5.7

My webinar “Multi-threaded Replication in MySQL 5.6 and 5.7″ on February 25 generated several excellent questions following the presentation (available here for playback along with the slides). I didn’t have time to answer many of the questions during the session and so in this post I answer all of them. Thanks to everyone who attended!

Q: What do you expect from MTS with logical clock? Do you think performance would be good as with per database?
A: MTS with 5.6 is not usable if you have a single database. I do not have numbers, but this is quite frequent. With 5.7 everyone should be able to benefit from multi-threaded replication.

Q: When MySQL 5.6 was released, performance of MTS was lower, than in 5.5, for example. Is this addressed now?
A: I am not sure which …

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MySQL Workbench 6.3.2 RC has been released

The MySQL developer tools team is pleased to announce 6.3.2 RC - the first release candidate for MySQL Workbench 6.3

For the full list of changes in this revision, visit

http://dev.mysql.com/doc/relnotes/workbench/en/changes-6-3.html

For detailed information about the new features, see What’s
New in MySQL Workbench 6.3
http://dev.mysql.com/doc/workbench/en/wb-what-is-new-63.html

For discussion, join the MySQL Workbench Forums:
http://forums.mysql.com/index.php?151

Download MySQL Workbench 6.3.2 RC now, for Windows, Mac OS X 10.7+,
Oracle Linux 6 and 7, Fedora 20 and Fedora 21, Ubuntu 14.04 and …

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Design for “seckilling ” on MySQL

Today I read a nice article , which give a new design for mysql database . In this article , Author (Mr.lou) uses OneSQL (a branch of MySQL) for the whole test.

you can read from : http://www.onexsoft.com/?page_id=378

This article explain how to use mysql in seckilling scenario (especially for E-Commerce commany )

If you want to use transaction in RDBMS database, you must manual start transaction and commit in the end of your operation.
So,commit will be cost of the total process, round-trip cost will be the most important cost as author said

(For simple update operations, without regard to conflict of IO and locks, a statement execution time is about 0.1ms, network delay under normal conditions is 0.4-0.8ms, that the waiting time is longer than the transaction commit time to really notice the SQL execution several times, showing that the …

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Initialize Your MySQL 5.7 Instances with Ease

MySQL 5.7.6 brings in a simplification that solves the very first problem that I encountered back in the days when I first started using MySQL 5.0. Namely…

How do I create a new database instance?

I know it sounds like a very basic question. But as it turned out, the answer was not that simple. I tried mysqld --help. Nothing there. And then, after reading the manual and trying out the complex command line (including redirection) based steps a couple of times, I just resorted to employing the mysql-test-run.pl test suite driver to create the initial system tables and data for me.

Obviously this has …

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MySQL Workbench 6.3.2 RC has been released

Dear MySQL users,

The MySQL developer tools team announces 6.3.2 RC – the first release
candidate for MySQL Workbench 6.3.

For the full list of changes in this revision, visit
http://dev.mysql.com/doc/relnotes/workbench/en/changes-6-3.html

For detailed information about the new features, see What’s
New in MySQL Workbench 6.3
http://dev.mysql.com/doc/workbench/en/wb-what-is-new-63.html

For discussion, join the MySQL Workbench Forums:
http://forums.mysql.com/index.php?151

Download MySQL Workbench 6.3.2 RC now, for Windows, Mac OS X 10.7+,
Oracle Linux 6 and 7, Fedora 20 and Fedora 21, Ubuntu 14.04 and …

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