Showing entries 10153 to 10162 of 43992
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What is a data type?

I'd suppose that these statements are generally accepted:

A data type is a set of values.

So any value that belongs to that set is said to "have" or "belong to" that data type.

And any column which is defined as "of" that data type is going to contain values which have that data type, only.

For example a column C may be defined as of type INTEGER and will only contain values which belong to the set of integers.

And now for the exceptions, details, caveats, and errors.

What is synonymous with data type?

There are no synonyms; no other term should ever be used.

Not datatype. Oracle's manual has "datatype" but IBM's doesn't and …

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Popular PHP Frameworks

My students often ask me about popular PHP frameworks and MySQL approaches. I wish a PHP framework choice was as clear as a JavaScript framework, like AngularJS. Unfortunately, PHP frameworks aren’t that clear cut.

It seems that the most popular PHP frameworks are: Laravel (1st), Phalcon (2nd), and Symphony2 (3rd). I found the following graphic (from December 2013) that highlights popularity by percentage of the market (though I can’t guarantee its accuracy). As far as jobs go, on Dice.com only Laravel had more than 3 positions referring to the framework by name. There were actually 42 PHP developer positions that mention Laravel out of 2,115 PHP developer …

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Testing TokuDB’s Group Commit Algorithm Improvement

The MySQL 5.6 Release has introduced some changes to how two phase commit works and is managed.  In particular, the commit phase of transactions to the binary log is now serialized and this behavior is something we identified fairly immediately.  We implement a group commit algorithm that needed to be altered so that TokuDB’s group commit to its recovery log would function effectively.

As part of our effort to verify the new Binary Log Group Commit functionality introduced in TokuDB 7.5.4 for Percona Server, we wanted to demonstrate the substantial increase in throughput scaling but also show the bottleneck caused by the skewed interaction between the binary log group commit algorithm in MySQL 5.6 and the transaction commit mechanism used in TokuDB 7.5.3 for Percona Server.  During our testing, we noticed that the throughput scaling was diminished when we turned on the binlog.

Here are the relevant system …

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File carving methods for the MySQL DBA

This is a long overdue blog post from London’s 44con Cyber Security conference back in September. A lot of old memories were brought to the front as it were; the one I’m going to cover in this blog post is: file carving.

So what is file carving? despite the terminology it’s not going to be a full roast dinner; unless you have an appetite for data which as you’re here I’m assuming you have.

The TL;DR of “what is file carving” is taking a target blob of data (often a multi GB / TB file) and reducing it in to targeted pieces of data, this could be for instance grabbing all the jpeg images in a packet capture / mysqldump; or pulling that single table/schema out of a huge mysqldump with –all-databases (if you’re not using mydumper you really …

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December London MySQL Meetup

The London MySQL Meetup Group hosted a new evening of MySQL related talks on December 11, this time in Canonical’s offices in the Blue Fin Building. Conveniently, it was timed so that it coincided with the Debian/Ubuntu packaging sprint, which I also attended.

We started with pizza, beer and small talk. Since this was my first meetup in London, there were lots of new and interesting people to meet and talk to.

The topic of the evening was “MySQL distributions: in the cloud and on bare metal”, but before we got that far, James Page and Robie Basak presented the results so far of our ongoing …

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Happy Holidays From Monitis General Manager

Dear Customer,

 

We at Monitis want to thank you for being with us this past year and tell you what a pleasure it has been to help you reach your everyday business goals. Monitis is growing fast and we sincerely appreciate the trust you put in us to help you manage all of your IT challenges.

 

During the past year we have worked diligently to expand and improve our suite of services to match your needs. We were especially excited to bring you new offerings such as;

 

  • Powerful integrations with industry leading partners such as; WHMCS, Zapier, PagerDuty and VictorOps
  • Enriching our Application monitoring and added; Log Monitor, Email Round Trip, MySQL and Node.js monitors
  • Real User Monitoring to a clear and quick view into the experience of your …
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Reducing VividCortex's Agent Overhead With Partial Network Capture

VividCortex now supports partial network capture to reduce load while monitoring MySQL database servers, where a tradeoff between full visibility and monitoring overhead might be desirable. This reduces our already-low overhead and enables higher accuracy in certain circumstances. Here’s a before-and-after image:

To review, one of ways we measure production MySQL query behavior at VividCortex is with libpcap, which sniffs network packets passively. Sometimes people think we’re “polling” or “sampling” to capture only a fraction of server activity, but in fact by default we see and analyze everything in full, packet-by-packet detail. And therein lies the problem.

The Problem

Our default network capture technique means we measure literally everything your server communicates with apps that query it. Every query, every error, everything.

We’ve worked extensively to optimize this process, reducing …

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New Option to Stop the Server If Binlogging Fails in MySQL 5.6

In this post I will try to explain the new MySQL binlog_error_action server option. This new option is available from MySQL 5.6.22 and later.

Background:
——————–
As part of MySQL replication all data changes that happen on the master server are recorded into a binary log so that they can be sent to slave and replayed there. If an error occurs that prevents mysqld from writing to the binary log (disk full, readonly file system, etc.) then the logs are simply disabled and operations continue on the master. This error mainly occurs during rotation of the binary log or while opening a binary log file.

This problem creates a serious potential for data loss …

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Testing backup locks during Xtrabackup SST on Percona XtraDB Cluster

Background on Backup Locks

I was very excited to see Backup locks support in release notes for the latest Percona XtraDB Cluster 5.6.21 release. For those who are not aware, backup locks offer an alternative to FLUSH TABLES WITH READ LOCK (FTWRL) in Xtrabackup. While Xtrabackup can hot-copy Innodb, everything else in MySQL must be locked (usually briefly) to get a consistent snapshot that lines up with Innodb. This includes all other storage engines, but also things like table schemas (even on Innodb) and async replication binary logs. You can skip this lock, but it isn’t …

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Happy Holidays From Monitis

Hello,

 

We at Monitis want to thank you for being with us this past year and tell you what a pleasure it has been to help you reach your everyday business goals. Monitis is growing fast and we sincerely appreciate the trust you put in us to help you manage all your IT challenges.

 

 

 

 

During the past year we have worked diligently to expand and improve our suite of services to match your needs. We were especially excited to bring you new offerings such as;

 
– Powerful integrations with industry leading partners such as; WHMCS, Zapier, PagerDuty and VictorOps

 

– Enriching our Application monitoring and added; Log Monitor, Email Round Trip, MySQL and Node.js monitors

 

– Real …

[Read more]
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