A comparison of Jaspersoft iReport and Pentaho Reporting
By Josh Tolley
October 2, 2011
I’ve recently been involved in reporting projects using both Jaspersoft’s iReport and Pentaho’s Reporting, so this seemed a good opportunity to compare the two. Both are Java-based, open source reporting systems which claim to build “pixel-perfect” documents (“pixel-perfect” means that when you put something somewhere on a report design, it doesn’t move around. That this isn’t taken for granted is a rant for another time). I have more experience with Pentaho than with Jaspersoft, and once reviewed a book on Pentaho; I’ll try to give the two a fair evaluation, but in the end I can’t promise my greater experience with Pentaho won’t affect my conclusions one way or the other. Both suites are available in open source and commercial flavors; I’ll consider only the open source versions here.
First let me point out that Jaspersoft and Pentaho both produce business intelligence software suites. The two suites exist in both community (open source) and enterprise (commercial) forms, are well worth comparing in their entirety, but I’m focusing principally on the report builder component of each, because that’s where my recent experience has led me. These report builder packages allow users to …
analytics database open-source reporting pentaho casepointer
Rails 3.1: Upgrading a Simple App — Part 2
By Steph Skardal
September 29, 2011
I recently wrote about upgrading a simple Rails app, which involved applying routing, mailer, ActiveRecord, etc. updates to my Rails 2.1.2 application. An equally important part of the upgrade is working with the asset pipeline, a framework that creates an architecture for managing JavaScript, CSS, and image assets in your Rails 3.1 application.
File Reorganization
Prior to the upgrade, my assets were organized in the following structure:
RAILS_ROOT/
public/
javascripts/
jquery.site.js
jquery.home.js
jquery.services.js
jquery.team.js
jquery.bios.js
...
stylesheets/
site.css
images/
.. a lot of images ..
As you can see, the JavaScript files were already split into page specific code that was included where it was needed. But the application had one global stylesheet which included styles for the entire site. In general, the site followed performance best practices of minimizing http requests with this organization.
In Rails 3.1, the generators encourage you to build out individual JavaScript and CSS files for each controller by creating the files upon each controller instantiation. While in development, those files are …
rails
PostgreSQL Serializable and Repeatable Read Switcheroo
By Greg Sabino Mullane
September 28, 2011
PostgreSQL allows for different transaction isolation levels to be specified. Because Bucardo needs a consistent snapshot of each database involved in replication to perform its work, the first thing that the Bucardo daemon does when connecting to a remote PostgreSQL database is:
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE READ WRITE;
The ‘READ WRITE’ bit sets us in read/write mode, just in case the entire database has been set to read only (a quick and easy way to make your slave databases non-writeable!). It also sets the transaction isolation level to ‘SERIALIZABLE’. At least, it used to. Now Bucardo uses ‘REPEATABLE READ’ like this:
SET TRANSACTION ISOLATION LEVEL REPEATABLE READ READ WRITE;
Why the change? In version 9.1 of PostgreSQL the concept of SSI (Serializable Snapshot Isolation) was introduced. How it actually works is a little complicated (follow the link for more detail), but before 9.1 PostgreSQL was only sort of doing serialized transactions when you asked for serializable mode. What it was really doing was repeatable read and not trying to really serialize the transactions. In 9.1, PostgreSQL is doing true serializable transactions. It also adds a new distinct …
bucardo database postgres
Another Post-Postgres Open Post
By Josh Williams
September 22, 2011
Well, that was fun! I’ve always found attending conferences to be an invigorating experience. The talks are generally very informative, it’s always nice to put a face to names seen online in the community, and between the “hall track”, lunches, and after-session social activities it’s difficult to not find engaging discussions.
My favorite presentations:
- Scaling servers with Skytools — seeing what it takes to balance several high-velocity nodes was intriguing.
- Mission Impossible — lots of good arguments for why Postgres can be an equivalent, nay, better replacement for an enterprise database.
- The PostgreSQL replication protocol — even if I never intend to write something that’ll interact with it directly, knowing how something like the new streaming replication works under the hood goes a long way to keeping it running at a higher level.
- True Serializable Transactions Are Here! — I’ll admit I haven’t had a chance to fully check out the changes to Serializable, so getting to hear some of the reasoning and stepping through some of the use cases was quite helpful.
But what of my talks? Monitoring went well—it seemed to get the message out. There was a lot of “gee, I have Postgres, …
conference postgres bucardo
Rails 3.1: Upgrading a Simple App — Part 1
By Steph Skardal
September 21, 2011
Here at End Point, I’ve worked with a few Rails 3 applications in production and a couple of Rails 3.1 apps in development, so I’ve become familiar with the new features and functionality including the Rails 3.1 Asset Pipeline that I mentioned earlier this year. I thought it was a good time to upgrade our website to Rails 3.1 and share the experience.
To start, here’s a quick summary of our website:
- Simple Rails application running on Rails 2.1.2 with no database
- Static pages throughout the site, fully cached
- Rake tasks to generate partials throughout the site to display dynamic blog content
- Site uses a moderate amount of jQuery and jQuery plugins.
- Site is optimized in terms of asset serving (ETags, Expires headers, CSS sprites, etc.)
While I’ve worked with a few Rails 3 apps, I haven’t been involved in the actual upgrade process myself. There are plenty of resources out there with upgrade advice, including a few RailsCasts (one, two, and three). My favorite resource was the rails_upgrade gem, a gem that is now officially supported by Rails to help with the upgrade process. I followed the instructions to install the gem (script/plugin install …
javascript jquery rails
Headed out to PgWest next week
By David Christensen
September 20, 2011
I’m gearing up to go out to San Jose to attend and speak at the PG West PostgreSQL conference in sunny San Jose. (Does anyone have directions…?)
I’m excited to again meet and mingle with more PostgreSQL experts and enthusiasts and look forward to the various talks, technical discussions, and social opportunities. My talk will be on Bucardo and many uses for it as a general tool. It’ll also cover additional changes coming down the pipe in Bucardo 5.
I look forward to seeing everyone!
conference postgres bucardo
Bucardo, 9.1, and you!
By Josh Williams
September 13, 2011
A little bit of bad news for Bucardo fans, Greg Sabino Mullane won’t be making Postgres Open due to scheduling conflicts. But not to worry, I’ll be giving the “Postgres masters, other slaves” talk in the meantime in his place.
In looking over the slides, one thing that catches my eye is how quickly Bucardo is adopting PostgreSQL 9.1 features. Specifically, Unlogged Tables will be very useful in boosting performance where Bucardo stages information about changed rows for multi-database updates. I also wonder if the enhanced Serializable Snapshot Isolation would be helpful in some situations. Innovation encouraging more innovation, gotta love open source!
If I hadn’t said it before, thanks to everyone that made Postgres 9.1 possible. Some of the other enhancements are just as exciting. For instance, I’m eager to see some creative uses for Writable CTE’s. And it’ll be very interesting to see what additional Foreign Data Wrappers pop up over time.
Now, back to packing…
conference postgres bucardo
OpenSSH known_hosts oddity
By Jon Jensen
September 12, 2011
A new version of the excellent OpenSSH was recently released, version 5.9. As you’d expect from such widely-used mature software, there are lots of minor improvements to enjoy rather than anything too major.
But what I want to write about today is a little surprise in how ssh handles multiple cached host keys in its known_hosts files.
I had wrongly thought that ssh stopped scanning known_hosts when it hit the first hostname or IP address match, such as happens with lookups in /etc/hosts. But that isn’t how it works. The sshd manual reads:
It is permissible (but not recommended) to have several lines or different host keys for the same names. This will inevitably happen when short forms of host names from different domains are put in the file. It is possible that the files contain conflicting information; authentication is accepted if valid information can be found from either file.
The “files” it refers to are the global /etc/ssh/known_hosts and the per-user ~/.ssh/known_hosts.
The surprise was that if there are multiple host key entries in ~/.ssh/known_hosts, say, for 10.0.0.1. If the first one has a non-matching host key, the ssh client tries the second one, and so on until it …
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