OK, so here is the next installment in the Drizzle replication article series. Today, I'll be talking about the flow of the Command message object through the CommandReplicator and CommandApplier APIs. If you missed the first article about the structure of the Command message and Google Protobuffers, you may want to read that first. We'll only be talking in this article about what happens on one server. We will be discussing the Command Log in the next article, and then discuss how messages are passed from one server to another. But, before we discuss those things, it is critical to first understand the CommandReplicator and CommandApplier plugin classes, which

If you  have asynchronous replication where the slave database is using MySQL Cluster then you can use the NDB API events functionality to mask/overwrite data. You might do this for example if the replica is to be used for generating reports where some of the data is sensitive and not relevant to those reports. Unlike stored procedures, NDB API events will be triggered on the slave.

The first step is to set up replication (master->slave rather than multi-master) as described in Setting up MySQL Asynchronous Replication for High Availability).

In this example, the following table definition is used:

mysql> use clusterdb;
mysql> create table ASSETS (CODE int not null primary key, VALUE

1. Create the database, table, and populate some data into it as shown below:
   
     [Read more...]
   A decade of open source IPOs

   +0 -0

   posted by The 451 Group on Thu 13 Aug 2009 07:30 UTC (Add To MySQL Librarian)
   Tags:

   (edit) IPO, Linux, 451 group, 451caostheory, 451group, caldera, caostheory, IPOs, mandriva, matt aslett, mattaslett, matthew aslett, matthewaslett, open-source, opensource, Red Hat, scourcefire, sourceforge, The 451 Group, the451group, Trolltech, turbolinux, VA linux

   (close)

   Red Hat is celebrating the 10 year anniversary of its initial public offering. An anniversary to be proud of for Red Hat, but one that has given The VAR Guy pause for thought about the relative success of open source in the past 10 years.

   “Would anyone have predicted that no additional open source companies would launch IPOs over the next decade? Ten years without an open source IPO … amazing and somewhat depressing for open source business advocates,” writes the VAR Guy.

   It is somewhat depressing that there are not more public open source vendors. However, the statement

     [Read more...]
   Fun With Information Schema!!

   +4 -0

   posted by Mark Schoonover on Thu 13 Aug 2009 07:09 UTC (Add To MySQL Librarian)
   Tags:

   (edit) mysql

   (close)

   Lately, I've had a few people ask me "How much data is in our database?". Sure, you can look at the file sizes of MyISAM tables and indexes and get a ballpark figure, but what if you need exact results, or are running InnoDB storage engine? That proves to be more challenging! In playing around with the information_schema, I've put together some queries to help:
   
   Calculate index sizes
   
   mysql> SELECT CONCAT(ROUND(SUM(index_length)/(1024*1024*1024), 2), ' GB') AS 'Total Index Size'
   FROM information_schema.TABLES WHERE table_schema LIKE 'database';
   
   +------------------+
   | Total Index Size |
   +------------------+
   | 1.70 GB |
   +------------------+
   1 row in set (1.60 sec)
   
   To calculate the total size of the data in the database
     [Read more...]
   Group commit and InnoDB

   +2 -0

   posted by Mark Callaghan on Wed 12 Aug 2009 23:04 UTC (Add To MySQL Librarian)
   Tags:

   (edit)

   (close)

   The InnoDB 1.0.4 plugin for MySQL 5.1 supports group commit. This is a big improvment for high-throughput workloads. I read the post from Yoshinori and then the source to understand the change. As I don't think I have ever described this correctly, I wanted to write it down for future reference. The protocol used to keep the binlog and InnoDB in sync on commit is implemented by ha_commit_trans and does the following:

   1. call binlog_prepare which does nothing
   2. call innodb_xa_prepare
      • call trx_prepare_for_mysql which writes the InnoDB in memory transaction log buffer to the current log file. The data written to the log file may include redo for other transactions so the optional fsync call done in this step may be amortized over several transactions. It then forces the writes to

     [Read more...]
   Indexing text columns in MySQL

   +2 -0

   posted by Fernando Ipar on Wed 12 Aug 2009 22:07 UTC (Add To MySQL Librarian)
   Tags:

   (edit) mysql, indexes, optimization, performance

   (close)

   This time, I’m talking about indexes for string typed columns. In particular, I’ll show a procedure I find useful while looking for good index length values for these columns.
   

   
   

   I’ll use a sample table called people.
   

   
   

   Here’s what it looks like:
   

   
   

   mysql> desc people;
   +————+——————+——+—–+———+—————-+
   | Field      | Type             | Null | Key | Default | Extra          |
   +————+——————+——+—–+———+—————-+
   | id         | int(11) unsigned | NO   | PRI | NULL    | auto_increment |
   | title      | varchar(250)     | NO   |     | NULL    |

     [Read more...]
   InnoDB Plugin 1.0.4 Now Available

   +0 -0

   posted by The Aquarium on Wed 12 Aug 2009 19:54 UTC (Add To MySQL Librarian)
   Tags:

   (edit) mysql, innodb, opensource, Oracle, sun

   (close)

   Ken Jacobs (Dr. DBA) has Announced Plugin 1.0.4. This release has significant performance improvements, including a number of key 3rd Party Contributions. Reactions from the community so far seem very positive ([

     [Read more...]