The latest from the MySQL community

While writing up a review on a database tool I discovered today, I was inspired to spark a discussion about database GUIs in general. The value of GUI tools for administering database systems like MySQL has been a topic of much debate. ...

Cluster

This blog entry describes how to install MySQL clusters on Solaris.

MySQL cluster consist of 3 seperate types of nodes:

• SQL nodes
• Storage nodes
• Management nodes

The SQL nodes are the nodes that applications can connect to. Internally SQL nodes connect to storage nodes to  process the queries and return the result set to the end client.

The storage nodes are controlled by management nodes. They do most of the work in processing the queries.

Managment nodes manages the entire cluster. They start and stop the data and SQL nodes and manage backups.

Lets start with the simplistic installation where all the nodes of the cluster are on the same box. Of course this is not how you would do a typical MySQL cluster installation...but this is just to get a feel of what is involved in MySQL cluster …

http://www.allthingsdistributed.com/2007/10/amazons_dynamo.html

"Most of these services only store and retrieve data by primary key
and do not require the complex querying and management functionality
offered by an RDBMS. This excess functionality requires expensive
hardware and highly skilled personnel for its operation, making it a
very inefficient solution. In addition, the available replication
technologies are limited and typically choose consistency over
availability."

1) Most web work is primary key.
2) Its not transactional.
3) Availability is more important then a lost data

When I joined MySQL four years ago, there was quite a lot of debate about product management. We didn't actually have any product managers and the view in Engineering was "we don't need 'em." The rationale was that we were so far behind in implementing features requested by customers that there was no need to have another opinion. "We already know exactly what we need to do" or "The Community tells us what we should focus on" were typical responses. It took me a while to convince people that product management could add value in helping to prioritize things and... READ MORE

The hiatus is over; I am reasonably settled at my new home. Therefore, HackMySQL.com is back to normal operation.

Parlez-vous le français? Je peux parler le français mais pas bien. Si vous voulez, on peut essayer à parler en français. Merci de votre patience.

In previous MySQL 6.0 alpha’s, the new Falcon engine didn’t handle ‘large’ transactions (meaning lots of rows inserted at one time) very well. You typically had to fall back to looping through the data with various commit points to get all the data inserted in a timely fashion.

The Falcon team should get some good kudos for putting out the latest alpha release that has much improved handling of large transactions. Below are just a few examples of large inserts on a Fedora Core box with a single CPU. Falcon was given a 200MB record cache size and InnoDB got a comparable 200MB buffer pool size.

mysql> show create table t_mG
*************************** 1. row ***************************
       Table: t_m
Create Table: CREATE TABLE `t_m` (
  `client_transaction_id` int(11) NOT NULL DEFAULT '0',
  `client_id` int(11) NOT NULL DEFAULT '0',
  `investment_id` int(11) NOT NULL DEFAULT '0',
  `action` varchar(10) NOT NULL,
  `price` …

Cluster

This blog entry describes how to install MySQL clusters on Solaris.

MySQL cluster consist of 3 seperate types of nodes:

• SQL nodes
• Storage nodes
• Management nodes

The SQL nodes are the nodes that applications can connect to. Internally SQL nodes connect to storage nodes to  process the queries and return the result set to the end client.

The storage nodes are controlled by management nodes. They do most of the work in processing the queries.

Managment nodes manages the entire cluster. They start and stop the data and SQL nodes and manage backups.

Lets start with the simplistic installation where all the nodes of the cluster are on the same box. Of course this is not how you would do a typical MySQL cluster installation...but this is just to get a feel of what is involved in MySQL cluster …

Cluster

This blog entry describes how to install MySQL clusters on Solaris.

MySQL cluster consist of 3 seperate types of nodes:

• SQL nodes
• Storage nodes
• Management nodes

The SQL nodes are the nodes that applications can connect to. Internally SQL nodes connect to storage nodes to  process the queries and return the result set to the end client.

The storage nodes are controlled by management nodes. They do most of the work in processing the queries.

Managment nodes manages the entire cluster. They start and stop the data and SQL nodes and manage backups.

Lets start with the simplistic installation where all the nodes of the cluster are on the same box. Of course this is not how you would do a typical MySQL cluster installation...but this is just to get a feel of what is involved in MySQL cluster …

I’ve been asked by a number of people on how to do an upgrade from DRBD version 0.7 to DRBD 8. This upgrade does necessitate some minimal service down time, but it’s really not rocket science. And no, it does not force you to sync all of your data all over again.

Here’s my quick write-up.

An initial word of caution

Do not, I repeat do not attempt your upgrade unless you have at least read this blog entry to the finish.

Getting ready

First, you need to make sure that you have both your DRBD 8 userland binaries and kernel module ready to install. For our support customers, this means that you simply download two RPMs (or .debs) from our support web site. Make sure you have the right packages; you want those that match your system architecture and (for the kernel module) also your running kernel. Also, make sure you get …

Quick experiment with online changing of enabling/disabling compressed backups and local checkpoints (LCPs).

Backup is incredibly trivial and correct (even have some nodes do compressed, some not).

LCPs are a bit trickier when it comes to restore… currently how the code sits is that a block using the compressed file interface in NDBFS must specify if it wants to use the compressed read/write interface or not. So when you have LCPs that differ in compressed/non-compressed than the current config file setting, you’re not going to be able to restore them (although setting CompressedLCP=1 should let you restore either compressed or non-compressed LCPs).

At some point, I’ll probably move AsyncFile (our async file IO class) to just use azio alway, and modify azio to be transparent for non-compressed files…. I just have to fix up azio for direct io.