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Showing entries 1 to 30 of 62 Next 30 Older Entries

Displaying posts with tag: Technical (reset)

MariaDB 5.5.37 Overview and Highlights
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MariaDB 5.5.37 was recently released (it is the latest MariaDB 5.5), and is available for download here:

https://downloads.mariadb.org/mariadb/5.5.37/

This is a maintenance release, and so there are not too many big changes of note, just a number of normal bug fixes. However, there are a few items worth mentioning:

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Resolving Error 1918, System Error Code 126, When Installing MySQL ODBC Driver
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If you are installing MySQL ODBC Driver and encounter the following error:

Error 1918. Error installing ODBC driver MySQL ODBC 5.1 Driver, 
ODBC error 13: The setup routines for the MySQL ODBC 5.1 Driver 
could not be loaded due to system error code 126: 
The specified module could not be found. 
...\myodbc5S.dll).. Verify...

Then you will need to install the Microsoft Visual C++ 2010 Redistributable Package (select the appropriate one for your OS architecture below):

64-bit version:

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Improve your Stored Procedure Error Handling with GET DIAGNOSTICS
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In a previous post, I discussed debugging stored procedures with RESIGNAL, which is of great value when troubleshooting errors raised by your stored procedures, functions, triggers, and events as of MySQL/MariaDB 5.5.

However, as of MySQL 5.6 and MariaDB 10.0, there is GET DIAGNOSTICS, which can be used to get the exact error details as well.

RESIGNAL just outputs the error, as it comes from the server, for instance:

ERROR 1146 (42S02): Table 'db1.t1' doesn't exist

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Quickly Debugging Stored Procedures, Functions, Triggers, and Events with RESIGNAL
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I was recently debugging a stored procedure and could not easily identify the underlying reason for why it was failing.

It had a standard exit handler catch-all for SQLEXCEPTION, which was:

DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN
SELECT ...;
END;

When there was an error, it didn't really output anything useful.

As of MySQL 5.5, there is RESIGNAL:

"RESIGNAL passes on the error condition information that is available during execution of a condition handler within a compound statement inside a stored procedure or function, trigger, or event."

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MariaDB 10 GTID Explained
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MariaDB replication in general works as follows: on a master server, all updates to the database are written into the binary log as binlog events, a slave server connects to the master and reads the binlog events and applies the events locally to replicate the same changes as done on the master. A server can be both a master and a slave at the same time, it is thus possible for binlog events to replicated through multiple levels of servers.

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InnoDB Primary Key versus Secondary Index: An Interesting Lesson from EXPLAIN
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I ran into an interesting issue today, while examining some EXPLAIN outputs, and wanted to share the findings, as some of this is undocumented.

Basically, you can start with a very simple InnoDB table - 2 INT columns, Primary Key (PK) on the 1st column, regular index on the 2nd:

CREATE TABLE `t1` (
  `id1` int(10) unsigned NOT NULL,
  `id2` int(10) unsigned DEFAULT NULL,
  PRIMARY KEY (`id1`),
  KEY `id2` (`id2`)
) ENGINE=InnoDB;

The query is:

SELECT id1 FROM t1;

This is a straight-forward query with no WHERE clause.

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MySQL to MariaDB migration: handling privilege table differences when using mysqldump
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Migrating from MySQL to MariaDB is generally a straightforward procedure: you can shut down MySQL, install MariaDB, and start it up with a very good chance of success. When upgrading/crossgrading/migrating from one release of MySQL or MariaDB to another, it is important to run mysql_upgrade. The same is true when migrating from MySQL to MariaDB, in part because MariaDB has some different definitions for certain privilege tables. This means that the structures of the MySQL tables are not valid for MariaDB, a problem easily fixed by mysql_upgrade, unless you are trying to import an SQL dump from MySQL that creates tables using the old-style structures and tries to interact with them before it is possible to run mysql_upgrade. Let's take a look at why this is a problem and how to solve

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MariaDB 10.0.8 Overview and Highlights
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MariaDB 10.0.8 was recently released as RC ("Release Candidate"), and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.8/

This is the first RC release of MariaDB 10.0. It is primarily a bug-fix and polishing release, and all features planned for MariaDB 10.0 GA are included in this release.

There were 6 notable changes in MariaDB 10.0.8:

  • InnoDB upgraded to version 5.6.14
  • read more

    MaxScale - We'd Love to Know Your Thoughts
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    As you've heard, MaxScale was recently released, and we'd love for you to try it out and let us know your thoughts.

    Anders Karlsson and Ivan Zoratti have written some excellent posts on downloading and setting it up, so if you're intersted in that, please see their respective posts for quick, detailed instructions.

    read more

    MaxScale - Do we need another MySQL proxy?
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    I have spent some time thinking about and working on a project that went public on GitHub at the beginning of this year. That project is called MaxScale and is primarily a proxy server for MySQL/MariaDB databases, although it can be something much more than this. The obvious and often asked question is why do we need another proxy? I want to try to give you a flavor for what MaxScale is and why I think there is a need for a tool like MaxScale.

    The architecture of MaxScale makes it different from your average proxy

    • MaxScale has awareness of the content it is shipping.

    read more

    Activating Auditing for MariaDB and MySQL in 5 Minutes
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    Do you want to learn more about the MariaDB Audit-Plugin? Join Ralf Gebhardt on 5.12.2013 for his live webcast: http://www.skysql.com/why-skysql/webinars/mariadb-audit-plugin-overview

    Introduction

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    High Availability for Drupal Part 1 - Investigating the Issues
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    Drupal is one of the most popular Content Management Systems (CMS) and is used increasingly in high-visibility sites, such as www.whitehouse.gov. This has brought a lot of attention on how to get the most performance out of Drupal and how to improve the availability of such sites. In this blog series I'll take you through the basics and on through to designing your own HA Drupal site.

    But first, we need to understand what the challenges are in getting Drupal (or indeed any CMS) working on multiple servers in such a way as to ensure high availability and performance.

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    Google Docs sharing and its cloudy usability
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    Background: SkySQL is a distributed company. Nearly all of us work from home. To be productive, we need to emulate the best aspects of collaborating as if we were working next to one another. Given that nearly all of us had worked under similar distributed conditions at MySQL AB, we knew what we were getting into when we were founded. Obviously, we wanted to learn from our past experiences when making our choices for tools and processes.

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    How Galera does Rolling Schema Upgrade, really
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    This post is about a fairly technical detail of how Galera works. I'm writing it down in preparation for testing this feature so that I can agree with Alex whether to file a bug or not. I'm sharing it on my blog just in case someone else might benefit from learning this.

    Galera 2.0 introduces rolling schema upgrades. This is a new way to do non-blocking schema changes in MySQL.

    As the name suggests, it is done as a rolling upgrade. Having seen clusters doing rolling upgrades before, I assumed this is what happens:

    • Execute alter table on Node 1.
    • Node 1 is removed from the cluster and stops processing transactions.
    • Node 1 completes alter table.
    • Node 1 re-joins cluster and catches up so that it is in sync.

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    Now available: Slides from Percona Live and Linuxcon Europe
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    The slides from last week’s talks I (co-)presented at Percona Live and Linuxcon Europe are now available from our web site.

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    LINBIT Technical Guides now available on our web site
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    If you run (or plan to deploy) high availability clusters — with or without DRBD — you might find a new section on our web site handy. Our Technical Guides collection is a compilation of LINBIT expert HA knowledge, which we’re opening up to everyone.

    Yes, this also includes PDF versions of the DRBD User’s Guide and the Linux-HA User’s Guide.

    More Technical Guides will be added as we go along. LINBIT Cluster Stack support customers will receive new Tech Guides approximately

      [Read more...]
    10 Steps: MySQL Monitoring through Nagios: Install & Configure
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    Nagios is a powerful monitoring system and here we will learn how to monitor MySQL through Nagios. We will be installing Nagios, required plugins and configuring it to monitor MySQL […]
    DRBD != fsck != DIX
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    Every once in a while, we hear of users with corruption in a file system that sits on top of DRBD. That may be easy or tricky to resolve. If you’re lucky, a simple fsck will resolve the corruption. If you’re not quite that lucky, you may have to get out your backups.

    But that’s typically not DRBD’s fault. Typically not at all, not in the least bit. DRBD is a block device, and as such it has no idea what rests on top of it. It has no concept of a filesystem, let alone its integrity. That of course is true for any other block device as well. If you have, say, RAID-1, and something corrupts the file system on top of it, then of course that corruption will be happily replicated across both component devices. DRBD is no different, except that its component devices are stored across distinct physical nodes.

    And even if everything about your filesystem

      [Read more...]
    LinuxTag presentation now available for download
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    A live recording of my LinuxTag 2010 presentation entitled Storage Done Right: Building a Resilient, Distributed, Highly Available Open Source iSCSI SAN is now available from our web site. If you want to find out how to build a complete SAN from 100% open source, do take a look!

    I do apologize for the less-than-optimal sound quality. I did the recording myself with my laptop mike, so unfortunately there’s quite a bit of clipping in the audio track. I hope my ramblings are still somewhat audible.



      [Read more...]
    In case you haven’t noticed, we no longer manage clusters with XML
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    While Yves presents a valid approach for managing NDB with Pacemaker and the anything Linux-HA resource agent (a generic wrapper for any daemon based application), the XML configuration shown is likely to have people running away screaming. This is how we had to do things back in the Heartbeat 2 days, which meant that as a cluster admin you would permanently run around with a loaded cocked shotgun with the muzzle pressed firmly against your foot.

    Those days are long gone. Please don’t do this anymore. You also no longer need to use the low-level tools such as cibadmin or crm_attribute.

      [Read more...]
    MySQL related file types and basic information
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    This post covers the basic information of files that MySQL Server uses / creates for various tasks. my.cnf : It is the main configuration file for MySQL. You may find […]
    SQL syntax with /*! c-style comments in MySQLdump
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    In mysql we have — , /* and /*! comments.  This post is mainly about very basic c-style comments. /*! : C-Style comments in MySQL We normally see comments in […]
    Ideas for select all columns but one mysql stored procedure
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    Assume we’ve a table with 100 rows and we need to select all columns but one. The problem is headache of actually typing out all 99 required columns!! Solutions / […]
    5 useful MySQL Command Options-pager-prompt-rehash-tee-system
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    There are set of commands that MySQL itself interprets. You may use “help” or “\h” at the mysql> prompt to list them. Below are the 5 most useful MySQL Command […]
    MyDumpSplitter-Extract tables from mysqldump | MySQL dump splitter – shell script
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    A lot of articles have been written on splitting mysqldump (mysql dump splitter) and grab required tables. Long back when Shlomi had suggested a “sed” way, I actually shell scripted […]
    Stored procedure to add-remove prefix by rename table mysql
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    Here is one more procedure – (this time) for mass renaming of table. Adding and Removing table-name prefixes A friend of mine was renaming 100+ tables by using replace methods […]
    Load Delimited Data – CSV to MySQL, Excel to MySQL Database
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    Loading csv to MySQL or any delimited data files to MySQL database is a very common task frequently questioned about and almost every-time LOAD DATA INFILE come into rescue. In […]
    MySQL Memory Usage Limits on 32 bit Linux
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    I’m having RHEL 5 (32-bit) and MySQL-5. I was trying to check how much is the Memory Utilization limits for MySQL 5 on 32bit OS. We can easily calculate the […]
    MySQL Certification Free Retake: Get TWO chances to get MySQL Certified
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    Recently MySQL has offered MySQL Certification Free Retake on both DBA or Developer Certifications for a limited time. For MySQL Certifications: 1. MySQL 5.0 Data Base Administrator Certification (SCMDBA) - […]
    Monty: Help Saving MySQL – The Oracle & EC
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    We all are aware about the acquisition happened to MySQL; Sun and now Oracle. A common understanding tells me that a business will always seek profit; so will Oracle. And […]
    Showing entries 1 to 30 of 62 Next 30 Older Entries

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