This is not a new feature by any means but it is a question I
have happen to see pop up every now and then. So a quick example
is following.
To generate a random integer within MySQL you can use the Floor
and Rand functions. The MySQL manual documents this here:
http://dev.mysql.com/doc/refman/5.5/en/mathematical-functions.html#function_rand
"To obtain a random integer R in the range i <=
R < j, use the expression FLOOR(i + RAND() * (j –
i))"
So to give an example:
> SET @I = 3; # lower range
> SET @J = 43 - @I; # max range minus lower range
> SELECT FLOOR( @I + (RAND() * @J )) as
lottery_numbers\G
…
If you need analytics insight into huge data sets in real-time, you probably at some point googled “Big Data”, “Columnar Database”, “SQL on Hadoop”, “MySQL Storage Engine”, “Massively Parallel Database” or “Distributed Database”. And it is highly likely that you came across InfiniDB as one of the results. In this post, I will help you with get to know InfiniDB and to see how these google keywords applies to InfiniDB.
MySQL Fabric – High Availability & Automated Sharding for MySQL
MySQL Fabric is built around an extensible and open source framework for managing farms of MySQL Servers. Currently two features have been implemented – High Availability (built on top of MySQL Replication) and scaling out using data sharding. These features can be used in isolation or in combination. MySQL Fabric aware connectors allow transactions and queries to be routed to the correct servers without the need for a proxy node, so operations run as quickly as ever. In this webinar you will learn what MySQL Fabric is, what it can achieve and how it is used – by DBAs, Dev-Ops and developers. You’ll also be exposed to what is happening under the covers. In addition to the presentation, there will be live on-line Q&A with the engineering team. This is a great opportunity to learn about the latest developments directly from the people building them. …
[Read more]
On Thursday (19th June), Mats Kindahl and I will be presenting a free webinar on why and how you should be using MySQL Fabric to add Sharding (scaling out reads & writes) and High Availability to MySQL. This product has only recently gone GA and so this is a good chance to discover it’s for you and to get your questions answered by the people who wrote the software! All you need to do is register for the MySQL Fabric webinar here.
Abstract
MySQL Fabric is built around an extensible and open source framework for managing farms of MySQL Servers. Currently two features have been implemented – High Availability (built on top of MySQL Replication) and scaling out using …
[Read more]Release Notes Changelog What is MariaDB 10.0?
MariaDB APT and YUM Repository Configuration Generator
The MariaDB project is pleased to announce the immediate availability of MariaDB 10.0.12. This is a Stable (GA) release.
See the Release Notes and …
[Read more]We had really great webinar on Replicating to/from Oracle earliest this month, and you can view the recording of that Webinar here.
A good sign of how great a Webinar was is the questions that come afterwards, and we didn’t get through them all. so here are all the questions and answers for the entire webinar.
Q: What is the overhead of Replicator on source database with asynchronous CDC?
A: With asynchronous operation there is no substantial CPU overhead (as with synchronous), but the amount of generated redo logs becomes bigger requiring more disk space and better log management to ensure that the space is used effectively.
Q: Do you support migration from Solaris/Oracle to Linux/Oracle?
A: The replication is not certified for use on Solaris, however, it is possible to …
[Read more]This week we discuss advanced pt-table-sync, including bidirectional sync. Ear Candy is starting MySQL on low-memory virtual machines, and At the Movies is "What's New With MySQL and MariaDB?"
pt-table-sync
Episode 188,
where we talked about pt-table-sync basics
pt-table-sync documentation
Options discussed:
--bidirectional
--chunk-column
--conflict-column
--conflict-comparison - greatest, least, newest, oldest, equals,
matches
--conflict-value
--conflict-error
I have just released version 3.5.5 of MyQuery, which is a
minor feature, cleanup and bugfix release. If you don't know
MyQuery since before, this is an Open-Source Windows based
MySQL and MariaDB ad-hoc query tool. What makes MyQuery
slightly different from all the other similar tools is that
MyQuery has a focus on SQL-scripting, allowing statements in a
script to be run one at the time, to restart a script where it
left of in the case of an error and some other features like
this. MyQuery features colour coded syntax as it uses
Scintilla for editing, and this is highly configurable. Also,
multiple editing tabs are supported. Another thing that
makes MyQuery stand out a bit is that it is highly
flexible. If you have SQL statements that you run often to
monitor the state of the server or your application, then it is
real easy to implement this as a simple tool accessible from the
MyQuery menu.
There …
In the latest release of MySQL Utilities 1.4.3 GA, the
performance of the mysqldbcompare utility has been considerably
improved along with some bug fixes. This blog briefly explains
some of the improvements that were made and shows evidence of the
increased performance of database comparison.
- A new step was added to the data consistency check. It now
executes a full table checksum, which is faster when no
differences are expected. The algorithm to find row differences
is only executed if this preliminary table
checksum fails.
- A new --skip-checksum-table option was added to skip this new step should you wish to (when you know there are differences it saves a bit of time).
- The current algorithm to find row differences was optimized to internally store and access the generated hash values.
What follows are some examples comparing the world database with …
[Read more]