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10 Newer Entries Showing entries 31 to 40 of 33316 10 Older Entries
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

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libAttachSQL Single Thread vs. libmysqlclient Multi Thread
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I have recently posted up benchmarks of libAttachSQL vs. libmysqlclient using sysbench. Whilst these are great and shows the results I hoped for, this isn't what we designed libAttachSQL for. It was designed for non-blocking many connections per thread.

With this in mind I spent today knocking up a quick benchmark tool which replicates the Sysbench "Select" test but using libAttachSQL's connection groups on a single thread. The code for this can be seen in the new AttachBench GitHub tree. Of course the secondary reason for this is to try and hammer the connection groups feature, which of course did find a bug when I scaled to around 32

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How to close POODLE SSLv3 security flaw (CVE-2014-3566)
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Padding Oracle On Downgraded Legacy Encryption

First off, the naming “convention” as of late for security issues has been terrible. The newest vulnerability (CVE­-2014-3566) is nicknamed POODLE, which at least is an acronym and as per the header above has some meaning.

The summary of this issue is that it is much the same as the earlier B.E.A.S.T (Browser Exploit Against SSL TLS), however there’s no known mitigation method in this case – other than entirely

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And the Bose Mobile Speaker DrupalCon prize draw winner is...
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Wed, 2014-10-15 17:46robertsilen

DrupalCon Amsterdam was a great event with a lot of energy! It was good to hear so many Drupal developers have already made the switch to MariaDB including the Drupal Association!

We are happy to announce the winner of the free prize draw for the Bose SoundLink Mini:

Matthew Radcliffe at Kosada

Matthew has received his Bose SoundLink Mini and is very happy with the prize!

If you missed Maria-Luisa's talk on Wednesday about the benefits of deploying Drupal on MariaDB check out the slides on slideshare.

Want to know more about MariaDB and Drupal?

  • See our blog series on
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Updates with secondary index maintenance: 5.7 vs previous releases
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My previous results for an update-only workload to a cached and IO-bound database used a table that did not require secondary index maintenance from the update. Prior to that I ran tests using mysqlslap and might have found a regression in InnoDB when the update requires secondary index maintenance (bug 74235). The mysqlslap test did all updates to the same row. The test I describe here chooses the row to update at random and this workload does not reproduce the worst case from bug 74235.

The results are that newer releases tend to do

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Experimenting with the new Data Dictionary Labs Release
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Labs releases are intended to provide early access to new features. As Gopal notes in his recent blog post About the Data Dictionary Labs Release, there is a notable restriction where upgrading from any previous MySQL database version is not supported.

Today, I thought I would demonstrate how to get the data dictionary lab up and running on a fresh Ubuntu 14.04 installation:

# Download from

# extract it to /usr/local/mysql
# more or less following instructions in INSTALL-BINARY

groupadd mysql
useradd -r -g mysql mysql
tar -xzf mysql-5.7.5-labs-dd-linux-el6-x86_64.tar.gz
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Rackspace doubling-down on open-source databases, Percona Server
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Founded in 1998, Rackspace has evolved over the years to address the way customers are using data – and more specifically, databases. The San Antonio-based company is fueling the adoption of cloud computing among organizations large and small.

Today Rackspace is doubling down on open source database technologies. Why? Because that’s where the industry is heading, according to Sean Anderson, Manager of Data Services at Rackspace. The company, he said, created a separate business unit of 100+ employees focused solely on database workloads.

The key technologies under the hood include both relational databases (e.g., MySQL,

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Sysbench IO-bound updates: MySQL 5.7 vs previous releases
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I repeated the sysbench update-only test after reducing the InnoDB buffer pool to 1G. The test database is 16G so the test should be IO-bound. MySQL 5.7.5 is 10% worse than 5.0.85 at 1 thread and much better at 8+ threads.

The previous blog post has more details on the setup. The configuration is not crash safe as the doublewrite buffer and binlog are disabled and innodb_flush_log_at_trx_commit=2. This test continued to use direct IO for InnoDB but this test requires a high rate of reads from storage. The previous test did many writes but no reads. A fast flash device is used for storage.

results at 1-thread

Only 1 table is used so there is a 2G database and 1G buffer pool. This test is less IO-bound than the many threads tests reported in

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Recover orphaned InnoDB partition tablespaces in MySQL
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A few months back, Michael wrote about reconnecting orphaned *.ibd files using MySQL 5.6. I will show you the same procedure, this time for partitioned tables. An InnoDB partition is also a self-contained tablespace in itself so you can use the same method described in the previous post.

To begin with, I have an example table with a few orphaned partitions and we will reconnect each partition one by one to the original table.

mysql [localhost] {msandbox} (recovery) > SHOW CREATE TABLE t1 G
*************************** 1. row ***************************
Table: t1
Create Table: CREATE TABLE `t1` (
KEY `h_date` (`h_date`)
/*!50100 PARTITION BY RANGE (year(h_date))
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libAttachSQL 0.9.0 RC - Connection Groups
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It has been just over 4 months since I started working on libAttachSQL for HP's Advanced Technology Group. Today marks the first (and hopefully only) RC release of the library.

Connection Groups

The only real new feature that has been added to 0.9.0 is the concept of connection groups which is something I'm pretty excited about. Internally libAttachSQL uses event loops to supply the non-blocking API. Connection Groups join a bunch of connections together into a group that uses a single event loop. This makes things much more efficient internally and makes applications easier to code too.

Here is a simplified example of how to use it (for a more detailed example see our example in the documentation).

First we

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10 Newer Entries Showing entries 31 to 40 of 33316 10 Older Entries

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