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Showing entries 1 to 10 of 33307 10 Older Entries
Percona XtraDB Cluster: How to run a 2-node cluster on a single server
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I reckon there’s little sense in running 2 or more Percona XtraDB Cluster (PXC) nodes in a single physical server other than for educational and testing purposes – but doing so is still useful in those cases. The most popular way of achieving this seems to be with server virtualization, such as making use of Vagrant boxes. But in the same way you can have multiple instances of MySQL running in parallel on the OS level in the form of concurrent mysqld processes, so too can you have multiple Percona XtraDB Cluster nodes. And the way to achieve this is precisely the same: using dedicated datadirs and different ports for each node.

 

Which ports?

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Improvements to the MySQL `IGNORE` Implementation
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In 5.7.5, as a part of the larger effort to improve error handling, we re-implemented the IGNORE clause (WL#6614). The IGNORE clause is a MySQL extension to the SQL standard. It affects the errors which occur for each row. The new implementation aims to make the behavior of the IGNORE clause more consistent.

Statements which support the IGNORE clause are:

  • INSERT [ IGNORE ]
  • UPDATE [ IGNORE ]
  • DELETE [ IGNORE ]
  • LOAD DATA [ IGNORE ]
  • LOAD XML [ IGNORE ]
  • CREATE TABLE… [ IGNORE ] SELECT

When the INSERT statement is used to insert a number of rows into a table, an exception during processing would normally abort the statement and return an error message. With the IGNORE keyword, rows that cause certain exceptions are ignored,

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XFS and EXT4 Testing Redux
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In my concluded testing post, I declared EXT4 my winner vs XFS for my scenario. My coworker, @keyurdg, was unwilling to let XFS lose out and made a few observations:

  • XFS wasn’t *really* being formatted optimally for the RAID stripe size
  • XFS wasn’t being mounted with the inode64 option which means that all of the inodes are kept in the first 2TB. (Side note: inode64 option is default in newer kernels but not on CentOS 6’s 2.6.32)
  • Single threaded testing isn’t entirely accurate
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MySQL: The most popular open source database for WWW
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(Note : This an Article from last year when MySQL5.6 was released)

While Database technology is one of the oldest branches of computer science, it remains a fundamental computer technology that continues to attract new research. The current focus of Databases technology is towards adapting hot new tends like multi-core chips, solid state devices, NOSQL and Cloud. So what does a contemporary internet developer look for in a database for the internet era? And why does MySQL remain the most popular database for the web?

 

For a database to be useful while developing products for the Web, the most important requirements are that it should be quick and easy to download, quick to set up, powerful enough to get the job done, be fast and flexible to use and finally be scalable on the newest hardware. Compatibility with

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High Performance Drupal with MariaDB
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Mon, 2014-10-20 09:31maria-luisaraviol

I am back from 2014 Amsterdam Drupalcon where MariaDB Corporation was present as sponsor. It was my first time there and I must say I was really impressed by the amount of people attending the conference (around 2300 people) and the interest that the people showed for MariaDB.

We had many conversations with several kind of engineers, developers, providers and just for a few of them MariaDB was something new to discover; the great majority of them either were already using it or were planning to do it but they did not manage to find some “free” time to do it yet.

What impressed me, was that almost all of the MariaDB happy users just replaced their previous database server installation (MySQL or Percona) with

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MariaDB 10.1.1: no more .frm’s for performance_schema tables
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Yes! In MariaDB 10.1.1 tables in PERFORMANCE_SCHEMA do not use .frm files. These files are not created, not read — in fact, PERFORMANCE_SCHEMA tables never touch the disk at all.

This became possible due to a lesser-known feature of MariaDB — new table discovery (“old table discovery” was implemented in MySQL for NDB Cluster in 2004), implemented in MariaDB 10.0.2. Instead of reading and parsing .frm files, MariaDB simply asks PERFORMANCE_SCHEMA table, what structure it has, and because these tables always have a fixed structure, the table directly returns it to MariaDB with no need for any external data dictionary.

It also means, you never need to upgrade PERFORMANCE_SCHEMA tables, they

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Making UUID() and RAND() replication safe
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MySQL's UUID() and RAND() functions both provide with (pseudo) indeterministic result. UUID()'s result is moreover bound to the host on which it executes. For this reason, both are unsafe to replicate with STATEMENT binlog format. As an example, consider:

master> create table test.uuid_test (id int, u varchar(64));

master> insert into test.uuid_test values (1, UUID());
Query OK, 1 row affected, 1 warning (0.03 sec)

master> select * from test.uuid_test;
+------+--------------------------------------+
| id   |
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Improved Fault Diagnosis UI
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In our efforts to improve MySQL monitoring, we recently enhanced our fault diagnosis UI. Adaptive Fault Detection has been an integral part of our suite, and we are excited for the UI updates that will help you better manage your databases.

The new release provides a more compact view, allowing you to quickly assess potential problems before they become bigger. Notice how a tiny, tiny server stall was caught by our algorithm. Fault detection has allowed us to get remarkable results from our weak EC2 boxes by keeping them running really cleanly.

We have also added more sections showing metrics such as top processes, network sockets, and

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MariaDB 10.1 Brings Compound Statements
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A very old post of mine in 2009, MySQL’s stored procedure language could be so much more Useful suggested that it would be nice if MySQL could be adapted to use compound statements directly from the command line in a similar way to the language used for stored procedures. I’ve just seen that this seems to be possible now in MariaDB 10.1. See the release notes.

I now need to look at this. So thanks, it looks like this feature request is now available.

MariaDB 10.1.1: default roles
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As you all know MariaDB supported roles since the MariaDB release 10.0.5. They were implemented almost exactly as specified in the SQL Standard 2003, features T331 “Basic roles” and T332 “Extended Roles”.

But we were often hearing complains, users were not satisfied with purely standard set of features. In particular, the standard specified that one had to do

SET ROLE foobar;

to be able to use privileges, granted to the role foobar. This was not always convenient and sometimes not even possible (imagine, you need to grant role privileges to an account used by a closed-source application). There had to be some way to enable a given role automatically, when a user connects.

To solve this issue we have introduced the concept of a default role. A default role for given user is

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Showing entries 1 to 10 of 33307 10 Older Entries

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