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Displaying posts with tag: mysql (reset)

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   |
  [Read more...]
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.

[ERROR] COLLATION ‘utf8_general_ci’ is not valid for CHARACTER SET ‘latin1′
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Recently come across the problem where mysql server stop running and refusing to start with an error

The server quit without updating PID file (/var/run/mysqld/mysqld.pid)

Checked Mysql error log and found that an invalid usage of charset with collation causing problem.

error log:
141017 12:20:41 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data
while 15088 [ERROR] COLLATION 'utf8_general_ci' is not valid for CHARACTER SET 'latin1'
15088 [ERROR] Aborting

In this case mysqld trying to start  with  character-set-server = latin1 and collation-server = utf8_general_ci, which is not valid.
The following is the right charset value for COLLATION ‘utf8_general_ci’

node1 [localhost] {msandbox} ((none))





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Innodb transaction history often hides dangerous ‘debt’
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In many write-intensive workloads Innodb/XtraDB storage engines you may see hidden and dangerous “debt” being accumulated – unpurged transaction “history” which if not kept in check over time will cause serve performance regression or will take all free space and cause an outage. Let’s talk about where it comes from and what can you do to avoid running into the trouble.

Technical Background: InnoDB is an MVCC engine which means it keeps multiple versions of the rows in the database, and when rows are deleted or updated they are not immediately removed from the database but kept for some time – until they can be removed. For a majority of OLTP workloads they can be removed seconds after the change actually took place. In some cases though they might need to be kept for a long period of time

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Integrating ClusterControl with FreeIPA and Windows Active Directory for Authentication
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October 17, 2014 By Severalnines

Integrating ClusterControl with a corporate LDAP directory is a common task for many IT organizations. In an earlier blog, we showed you how to integrate ClusterControl with OpenLDAP. In this post, we will show you how to integrate with FreeIPA and Windows Active Directory. 

 

How ClusterControl Performs LDAP Authentication

 

ClusterControl supports up to LDAPv3 protocol based on RFC2307. More details on this

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MySQL 5.7.5-labs: Multi-source Replication
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Multi-source replication for MySQL has been released as a part of 5.7.5-labs-preview
downloadable from labs.mysql.com. It is one among the several features that are
cooking in the replication technologies at MySQL.  (For a birds eye view of all
replication features introduced in 5.7 and labs, look  at the blog posts here and here.

Previously, we have introduced a preliminary multi-source feature labs




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Percona Toolkit for MySQL with MySQL-SSL Connections
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I recently had a client ask me how to use Percona Toolkit tools with an SSL connection to MySQL (MySQL-SSL). SSL connections aren’t widely used in MySQL due to most installations being within an internal network. Still, there are cases where you could be accessing MySQL over public internet or even over a public “private” network (ex: WAN between two colo datacenters). In order to keep packet sniffers at bay, the connection to MySQL should be encrypted.

If you are connecting to Amazon RDS from home or office (ie: not within the AWS network) you better be encrypted!

As there is already a MySQL Performance Blog post on how to setup MySQL SSL

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Benchmarking Presentation at Percona Live London 2014
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In a few weeks I’m presenting “Performance Benchmarking: Tips, Tricks, and Lessons Learned” at Percona Live London 2014 (November 3-4). I continue to learn lessons and improve my benchmarking capabilities, so the content is a full upgrade from my presentation at Percona Live Santa Clara in April 2013. Anyone interested in achieving and sustaining the best performance out of their software/hardware/application should attend.

Also, Tokutek is sponsoring so we’ll be available in the expo hall throughout the

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InnoDB: Supporting Page Sizes of 32k and 64k
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In the new InnoDB lab release we support page sizes of 32k and 64k. This gives users even more choices on the page size, allowing you to further customize InnoDB for your particular workload.

There are some things worthy of note related to this new feature:

  • The extent size changes when the innodb_page_size is set 32k or 64k.
    The extent size is 2M for 32k page sizes, and 4M for 64k page sizes (the extent size is 1M for 4k, 8k, and 16k page sizes). If we do not enlarge the extent size then we will have too many extent headers on the allocation bitmap page, and the bitmap page will overflow.
  • The

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    Ignoring the lost+found Directory in your Datadir
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    I still get asked about the lost+found directory enough, and so I wanted to provide a current update.

    The lost+found directory is a filesystem directory created at the root level of a mapped drive. Thus this is common to see if you create your mysql datadir at the root level of a mapped drive.

    In the past, you could ignore it, if it wasn’t too problematic for you, or you could move your datadir down a level, and then it wouldn’t be created in the datadir anymore.

    However, there is now the –ignore-db-dir option. It is actually not too new (it’s been in MariaDB since 5.3.9 and 5.5.28, and in MySQL as of 5.6.3), but I don’t think many are too familiar with it.

    But when you do run into this problem, some/many would prefer to add a single line to the config file rather than move the datadir.

    To do this, just

      [Read more...]
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