Friday, June 14, 2013

Welcome Tungsten Replicator 2.1.0!


Overview


First off, the important news. Tungsten Replicator 2.1.0 was released today.
You can download it and give it a try right now.


Second, I would say that I am quite surprised at how much we have done in this release. The previous release (2.0.7) was in February, which is just a few months ago, and yet it looks like ages when I see the list of improvements, new features and bug fixes in the Release Notes. I did not realized it until I ran my last batch of checks to test the upgrade from the previous release, which I hadn’t run for quite a long time. It’s like when you see a son growing in front of your eyes day by day, and you don’t realize he’s grown a full foot until a distant relative comes visit you. The same happened to me here. I looked at the ./cookbook directory in 2.0.7, and I saw just a handful of commands (most of them now deprecated), and then at 2.1.0, which has about 30 new commands, all nicely categorized and advertised in the embedded documentation. If you are starting today with Tungsten Replicator 2.1.0, you can run


./cookbook/readme

and

./cookbook/help

Upgrade


If you were using Tungsten Replicator before, you need to know how to upgrade. If, by any unfortunate chance, you were not using the Cookbook recipes to run the installation, the method for installing is the following:

  • unpack the tarball in a staging directory
  • For each node in your deployment:
    • stop the replicator
    • run
      ./tools/update –release-directory=$PATH_TO_DEPLOYED_TUNGSTEN –host=$NODE
  • If your node has more than one service, restart the replicator


If you are using the cookbook, you can run an upgrade using

./cookbook/upgrade

This command will ask for your current topology and then show all the commands that you should run to perform the upgrade, including adapt the cookbook scripts to use the new deployment.

So, What’s New:

The list of goodies is long. All the gory details are in the Release Notes. Here I would like to mention the ones that have impressed me more.

Oracle Extractor Is Open Source

Up to the previous release, you could extract from MySQL and appley to Oracle, all using open source tools. If you wanted to extract from Oracle, you needed a commercial license. Now all the replication layer is completely open source. You can replicate from and to Oracle using Tungsten Replicator 2.1.0 under the terms of the GPL v2. However, you will still have to buy database licenses from Oracle!

Installation and Administration

There is a long list of utilities released inside the ./cookbook directory, which will help you install and maintain the cluster with a few strokes. See References #2 and #3 below. The thing that you should try right away is:

 # edit ./cookbook/COMMON_NODES.sh
 # edit ./cookbook/USER_VALUES.sh
 ./cookbook/validate_cluster

This will tell you if your servers are ready for deployment, without actually deploying anything.

Documentation!

We have hired a stellar professional writer (my former colleague at MySQL AB, well known book writer MC Brown) and the result is that our well intentional but rather unfocused documentation is now shaping up nicely. Among all the things that got explained, Tungsten Replicator has its own getting started section.

Metadata!

Tungsten replication tools now give information using JSON. Here’s a list of commands to try:

trepctl status -json
trepctl services -json -full
trepctl properties | less
thl list -headers -high 100 [-json]

For example:

$ trepctl services -json
[
{
"appliedLatency": "0.81",
"state": "ONLINE",
"role": "slave",
"appliedLastSeqno": "1",
"started": "true",
"serviceType": "local",
"serviceName": "cookbook"
} 
]

$ trepctl properties -filter replicator.service.comments
{
"replicator.service.comments": "false"
}

More Tools

My colleague Linas Virbalas has made the team (and several customers) happy when he created two new tools:

  • ddlscan, a Utility to Help Analyze and Migrate Database Schemas
  • the rename filter A supercharged filter that can rename mostly any object in a relational database, from schema down to columns.

Linas coded also the above mentioned JSON-based improvements.

MongoDB Installation

It was improved and tested better. It’s a pleasure top see how data from a relational database flow into a rival NoSQL repository as if they belong there! See reference #4 below.

More to Come

What’s listed here is what we have tested and documented. But software development is not a linear process. There is much more boiling in the cauldron, ready to be mixed into the soup of release 2.1.1.

We’re working hard at making filters better. You will see soon the long awaited documentation for them, and a simplified interface.

Another thing that I have tested and worked surprisingly well is the creation of Change Data Capture for MySQL. This is a feature that is usually asked for by Oracle users, but I tried it for MySQL and it allowed me to create shadow tables with the audit trace of their changes. I will write about that as soon as we smooth a few rough edges.

Scripting! This going to be huge. Much of it is already available in the source, but not fully documented or integrated yet. The thing that you will see soon in the open is a series of Ruby libraries (the same used by the very sophisticated Tungsten installation tools) that is exposed for general usage by testers and tool creators. While the main focus of this library is aimed at the commercial tools, there is a significant portion of work that needs to end up in the replicator, and as a result its usability will increase.

What else? I may have forgot something important amid all the excitement. If so, I will amend in my next articles. Happy hacking!

References

  1. Tungsten Replicator documentation
  2. Installing and Administering Tungsten Replicator - Part 1 - basics
  3. Installing and administering Tungsten Replicator - Part 2 : advanced
  4. Getting started with replication from MySQL to MongoDB

1 comment:

Eric Stone said...

Fantastic work, thank you!

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