This week again, the Log Buffer Edition covers the exciting and ever-evolving galaxies of Oracle, MySQL and SQL Server.
Oracle:
When does an Oracle process know it’s on Exadata?
MobaXterm 6.3 has been released. You can find the download and changelog in the usual place.
A new major release (version 3.0) of Randolf’s XPLAN_ASH tool is available for download.
Important !! Clustering Factor Calculation Improvement
…
[Read more]Having an InnoDB table without a PRIMARY KEY is not good. Many have known this for years, but exact opinions as to why have differed. From observation, it was clear to me that it impacted performance.
InnoDB stores its row data in the leaf nodes of the primary key B+tree structure, that means that it can’t work without… so if you don’t specify a PK, it makes one up. Seems pretty innocuous and shouldn’t actually perform any worse than an auto-inc field. Except that in reality the performance can be much much worse. Annoying. Naturally we recommend clients to always have a PK (auto-inc, a composite of foreign keys, or if need be a natural key) but production systems cannot always be quickly changed, depending on the app code adding a column is not something you can just do at the DBA level.
Recently my good friend and former colleague Jeremy Cole, who has been delving into the depths of InnoDB, asked me if I had any …
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It's now safe to backup InnoDB with mysqldumpBefore MySQL 5.6,
running mysqldump to make backup of InnoDB tables could cause
your backup to 'loose' some data. The problem is described in our
manual here.
In latest MySQL 5.6 this is no longer a problem, this means you
no longer risk 'loosing' data when using mysqlbackup together
with DDL statements on your InnoDB tables. If you are
interested in metadata-locking (MDL) you can read more about MDL
here.
To test this we need to create a few tables and also look at
which order mysqldump processes tables.
mysql> CREATE DATABASE ted;
mysql> USE ted;
mysql> CREATE TABLE `a` (`i` int(11) DEFAULT NULL)
ENGINE=InnoDB
mysql> CREATE …
Replication is a hot topic in MySQL 5.6, and for good reason: There are many excellent features that make it a strong well-supported feature, from the new Global Transaction Identifiers (GTIDs), to simplified replication configuration and automated failover using MySQL Utilities (now available in alpha as a separate download).
Circular Replication
The simplest topology consists of a master server that accepts changes, and slaves that replicate those changes from the master. A common requirement is for a network to have multiple servers that accept changes and replicate to each other. This is possible by means of circular …
[Read more]We use Amazon RDS for database servers and historically have had a practice of having smaller database server in QA and DEV to save cost. I would consider this a pretty common practice - but what I have also discovered is that it can lead to fixing non-bugs, or issues that will not arrise in production.
Let me try and describe a (~) worst case and some simple math to illustrate:
Production
QA
Production is serving its 10K queries/second with a 100% cache hit rate, but with the 1G less RAM, QA is only able to serve with a 99% cache hit rate. Each query touches on average 10 distinct …
[Read more]Hi Karthik,
Thanks for your feedback. I've made a note of your request. Either me or someone from our team will explain about the redo log format.
Rgds,
anna
This is the start of the heavy travel season for the MySQL Community Team. So if you are attending PHPTek, Drupalcon, Texas LinuxFest, SELF, Redhat Summit, or Lonestar PHP please make sure to say ‘hi’ while you are in Chicago, Portland, Austin, Charlotte, Boston, or Addison. This group of trips is starting with a swag bag full of MySQL stickers, thumb drives, and ‘boogie bots’
MySQL Boogie Bots
Talks PHPTek – Ten Things to Make Your MySQL Servers Faster and Happier — May 16th, 2:45p – 3:45p Texas Linuxfest – The Proper Care and Feeding of a MySQL Database for Linux Administrators — May 31st, 11:25a – 12:20p SELF – Two full days of MySQL talks but I am talking on Ten Things to Make Your MySQL Servers Faster and Happier. MySQL 101, MySQL User Administration — June 8th – 9th Redhat Summit – Big & Traditional Databases — June 12th, 4:40p – 5:50p</li?
So let’s clone our current Drupal 7.22 site from MySQL 5.1 that came with CentOS 6.4 and get it running on MySQL 5.6.
Upgrading MySQL 5.1 -> 5.6 has an official recommendation of making sure the intermediate 5.5 update is performed too. Please review Section 2.11.1 while you make a backup of all your data. Yes, you do have to make a backup. When you run the upgrade, there are tables in the mysql scehma that will be tweaked and skipping a step can make for a very messy late night in an attempt to recover.
An other thing to look for is that on occasion new reserved words are introduced that may conflict with column names in use in your schemas. So it pays to read through the release notes for new reserved words and then run a quick grep on your tables to be safe. If you find that there is a new reserved word …
[Read more]SkySQL & Monty Program’s MariaDB Team coming to a city near you!
During the last months we’ve worked hard on a new and exiting project!
“We’re making it easier to show your databases in a glance”
I’m very proud to reveal the project for the first time because I am convinced that Glimpsee will change the way you “watch” the status of your databases…
Glimpsee is not another monitoring tool, it is the easiest way we’ve found to make DBA’s life easier.
I can’t say more about Glimpsee at this point but keep in mind these few words: simple, simple and… simple!
An alpha release of Glimpsee is already running for a
lucky few. Register now to be the firsts to discover
Glimpsee!
…
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