Showing entries 11511 to 11520 of 44105
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High Availability with MySQL Fabric: Part I

In our previous post, we introduced the MySQL Fabric utility and said we would dig deeper into it. This post is the first part of our test of MySQL Fabric’s High Availability (HA) functionality.

Today, we’ll review MySQL Fabric’s HA concepts, and then walk you through the setup of a 3-node cluster with one Primary and two Secondaries, doing a few basic tests with it. In a second post, we will spend more time generating failure scenarios and documenting how Fabric handles them. (MySQL Fabric is an extensible framework to manage large farms of MySQL servers, with support for high-availability and sharding.)

Before we begin, we recommend you read this post by Oracle’s …

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MySQL Tech Day @Paris, 22/May-2014


The next MySQL TechDay is taking place in Paris, 22/May (the next week!!!) - if you're MySQL lover and will be in Paris area this day - hurry up to register on the event page and attend it - trust me, you'll not regret ;-))

We're continuing to follow our TechDay tradition:

  • the event is completely free (but places are limited, so you have to be registered to attend)
  • the content is pure technical and directly from Oracle engineering, no marketing ;-)
  • this is a true full day event, and we're reserving enough time to go in depth for each presented stuff..
  • the event is taking place in Oracle office in a pretty wide and comfortable amphitheater, covered by WiFi, so you may twit live about #mysqltechday and remain "connected" if this is a part of your constrains …
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Why ALTER TABLE runs faster on Percona Server 5.5 vs. MySQL 5.5

Some of us Perconians are at OpenStack summit this week in Atlanta. Matt Griffin, our director of product management, tweeted about the turbo-hipster CI talk about their experience of ALTER TABLEs running faster on Percona Server. Oracle’s Morgan Tocker then tweeted in response, asking why this was the case. I decided that the simplest way to answer that was here in this post.

The reason for this is the …

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A look at MySQL 5.7 DMR

So I figured it was about time I looked at MySQL 5.7. This is a high level overview, but I was looking over the MySQL 5.7 in a nutshell document:

So I am starting with a fresh Fedora 20 (Xfce) install.
Overall, I will review a few items that I found curious and interesting with MySQL 5.7. The nutshell has a lot of information so well worth a review.

I downloaded the MySQL-5.7.4-m14-1.linux_glibc2.5.x86_64.rpm-bundle.tar

The install was planned on doing the following
# tar -vxf …

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InnoDB with reduced page sizes wastes up to 6% of disk space

In InnoDB bugs found during research on InnoDB data storage I mentioned MySQL Bug #67963 which was then titled “InnoDB wastes 62 out of every 16384 pages”. I said:

InnoDB needs to occasionally allocate some internal bookkeeping pages; two for every 256 MiB of data. In order to do so, it allocates an extent (64 pages), allocates the two pages it needed, and then adds the remainder of the extent (62 free pages) to a list of extents to be used for single page allocations called FREE_FRAG. Almost nothing allocates pages from that list, so these pages go to waste.

This is fairly subtle, wasting only 0.37% of disk space in any large InnoDB table, but nonetheless interesting and quite fixable.

Wasting 0.37% of disk space was …

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Percona Live MySQL Conference and Expo

The post Percona Live MySQL Conference and Expo appeared first on Pythian.

MySQL EXPLAIN Explained

In years past, MySQL was a bit of a black box when it came to understanding what was happening and why. In MySQL 5.6 and 5.7, we’ve added many new features that provide much needed transparency and insight into the inner workings of MySQL. The single biggest feature was the new Performance Schema, but some other examples are:

  1. The ability to see what query generated a row based binary log event.
  2. The ability to see a tremendous amount of data points for InnoDB.
  3. The ability to see an extended query …
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Tips on benchmarking Go + MySQL

We just released, as an open source release, our new percona-agent (https://github.com/percona/percona-agent), the agent to work with Percona Cloud Tools. This agent is written in Go.

I will give a webinar titled “Monitoring All MySQL Metrics with Percona Cloud Tools” on June 25 that will cover the new features in percona-agent and Percona Cloud Tools, where I will also explain how it works. You are welcome to register now and join me. …

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Proposal to deprecate the old password format

Improving security has been a high priority for MySQL 5.7. To give you an idea of some of the changes to date, I recommend reading Todd Farmer's blog: Redefining --ssl option, Password expiration policy, AES256 encryption.

In MySQL 5.7, we are also proposing to remove the 'old' format for saving passwords. To provide some historical context:

  • The old password format is a 16-byte hash and considered to be cryptographically weak. Code appears online (I won't link to it) which allows the hash to be brute-forced in …
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An interesting case in ORDER BY LIMIT optimization

Recently, I was asked about an interesting case in ORDER BY … LIMIT optimization. Consider a table

create table tbl (
  …
  KEY key1(col1, col2),
  PRIMARY KEY (pk)
) engine=InnoDB;

Consider queries like:

  select * from tbl where col1=’foo’ and col2=123 order by pk limit 1;
  select * from tbl where col1=’bar’ and col2=123 order by pk limit 1;

These run nearly instantly. But, if one combines these two queries with col1='foo' and col1='bar' into one query with col1 IN ('foo','bar'):

  select * from tbl where col1 IN (’foo’,'bar’) and col2=123 order by pk limit 1;

then the query is be orders of magnitude slower than both of the queries with col1=const.

The first thing to note when doing investigation is to note that the table uses InnoDB engine, which has …

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