For those that weren’t able to attend the fantastic NoSQL Now Conference in San Jose last week, but are still interested in the slides about how people are doing Ad Hoc analytics on top of NoSQL data systems, here’s my slides from my presentation:

No sql now2011_review_of_adhoc_architectures View more presentations from ngoodman We obviously continue to hear from our community that LucidDB is a great solution sitting in front of a Big Data/NoSQL system. Allowing easy SQL access (including super fast, analytic database cached views) is a big win for reducing …

3 ways your MySQL migration project can shake you up

Once a development or operations team gets over the hurdle of open-source, and start to feel comfortable with the way software works outside of the enterprise world, they will likely start to settle in and feel comfortable.  Best not to get too cushy though for there are more surprises hiding around the corner.  Here are a few of the biggest ones.

1. Replication Is Not Perfect

Yes, you've installed MySQL, setup a slave, and got it replicating properly.  You check the slave and it's 0 seconds behind the master.  What's more you monitor the error log file, and have a check in place to alert you if something happens there.  Job completed, good job!

Not so fast.  Unfortunately this is not the end of the story.  Many MySQL replication slaves are not consistent with their masters, but they drift apart silently.  …

The problem For illustration, let's assume a MySQL server, with a couple of users (A, B, C, ...) who perform queries against some tables (T1, T2, etc) in the database.
Sooner of later, someone will want to know which user is performing which amount of table io against which table ... How can instrumentation help with that ?

A few days ago, we faced an interesting problem on one of our customer’s slave mysqld servers.  An Alter for adding a new column was run on master server took 542 seconds where as it took few hours on the slave server to complete due to a SELECT blocking the Alter was not allowed to complete.

Here is the the select on the master server and it’s execution time from the binary logs.

# at 825737566
#110720 19:55:21 server id 31415  end_log_pos 825737730         Query   thread_id=83250629      exec_time=542   error_code=0
use collect/*!*/;
SET TIMESTAMP=1311216921/*!*/;
/*!\C latin1 *//*!*/;
SET @@session.character_set_client=8,@@session.collation_connection=8,@@session.collation_server=8/*!*/;
ALTER TABLE `track` ADD `source_track_id` int(10) UNSIGNED NULL DEFAULT NULL  AFTER `vendor_track_id`
/*!*/;

Alter statement completed well on the master and it got blocked by a SELECT on the slave where as the time frames of the …

 After publishing MySQL MHA in the end of July, I received a few requests for supporting multi-master configuration. So I spent time for extending MHA for supporting multi-master, and now it's published at a separated GitHub branch (a new development tree). I'll take some time for people to evaluate the new feature, and after verifying it's stable enough, I'll merge it to the main branch and will release as a new version (tarball release).

The below is procedures to install MHA Manager multi-master tree.

$ git clone git://github.com/yoshinorim/MySQL-MasterHA-Manager.git

$ cd MySQL-MasterHA-Manager

$ git checkout -b multimaster origin/multimaster
 …

This is the first in a series of posts on MySQL® for those new to the database, or those migrating from another DBMS.

So you've made the decision to try MySQL.  Now you just have to get it installed. Luckily for most purposes MySQL is quite often already available.  If you have a Linux installation then chances are that both the server and client are installed.  If you are planning on using MySQL for your website, chances are the hosting provider gives you several MySQL databases for your use.

Before diving in too deep though, let's get some background and terminology out of the way.

What is MySQL?

This depends.  MySQL was a company, is a trademark, is an ecosystem and is the name of arguably the most popular relational database management system (RDBMS) on the planet.  Originally developed by MySQL AB, MySQL (both the database and the trademark) are now owned by Oracle Corporation. But …

MySQL is needlessly slow at accepting new connections. People usually work around that by having various sorts of connection pools, but there’s always a scale at which connection pools are not feasible. Sometimes connection avalanches come unexpected, and even if MySQL would have no trouble dealing with queries, it will have problems letting clients in. Something has to be done about it.

Lots of these problems have been low hanging fruits for years – it ‘was not detected’ by benchmarks because everyone who benchmarks MySQL would know that persistent connections are much faster and therefore wouldn’t look at connection speeds anymore.

Usually people attribute most of slowness to the LOCK_thread_count mutex – they are only partially right. This mutex does not just handle the counter of active running connections, but pretty much every operation that deals with increase or decrease of threads (thread cache, active thread …

Just wanted to record for the history books that:


drizzle> select js_eval('var d = new Date(); "Drizzle started running JavaScript at: " + d;')\g
+----------------------------------------------------------------------------------+
| js_eval('var d = new Date(); "Drizzle started running JavaScript at: " + d;') |
+----------------------------------------------------------------------------------+
| Drizzle started running JavaScript at: Mon Aug 29 2011 00:23:31 GMT+0300 (EEST) |
+----------------------------------------------------------------------------------+
1 row in set (0.001792 sec)


I will push this onto launchpad tomorrow, after a good nights sleep and final code cleanups.

read more

Introduction to Search with Sphinx

Introduction to Search with Sphinx by Andrew Aksyonoff, O’Reilly Media 2011. About 146 pages. (Here’s a link to the publisher’s page.)

This is an engaging short introduction to Sphinx. At 146 pages, you shouldn’t expect it to go into every detail, and it doesn’t. There are major topics that it omits entirely or mentions only tangentially, such as distributed searching across a cluster of machines, real-time updating of indexes and attributes, and so on. But although the book doesn’t boil the ocean, it does a great job at covering an introductory …

Did you know that you can subscribe to Oracle Magazine for free? It doesn’t have much content on MySQL, but it’s not such a bad thing to stay at least a little bit in touch with what Oracle is doing with the Oracle database server, too. You can subscribe online free.

Further Reading:

• Subscribe
• Spring 2008 issue of MySQL Magazine
• Thanks Oracle for the ACE Award
• Oracle is not screwing MySQL
…