Select from a map in GSP?

Logging in grails 1.3.7

Logging capabilities haven improved a lot in grails 2.0, but my main project is still running on grails 1.3.7 and somehow I never managed to get any of the profiling plugins to work. I was suspecting that my application made a lot of repetitive and unnecessary requests to the SQL database so I needed a way to figure out what was happening between hibernate and the JDBC connection. Hibernate comes with its own logging but unfortunately it doesn't tell you anything about the response time of the database. So I was digging google and found this very promising approach on http://piraguaconsulting.blogspot.com/2010/06/grails-p6spy-and-sql-profiler.html, where p6spy basically replaces your database driver with a shadow version that logs all communication. Unfortunately this didn't work for my project. I use a C3P0 connection pool and the shadow driver of p6spy can't handle that (at least not as far as I could see). A pity since it seemed to be a good idea especially in combination with http://sourceforge.net/projects/sqlprofiler/ which combines the logging with a nice GUI.

However, this approach gave me a basic idea of what I was looking for and googling deeper I found http://code.google.com/p/log4jdbc/ which in contrast to p6spy is actively developed. Hooking it up with grails is super easy. You add the lib file to your project, exchange the database driver in your dataSource config with

net.sf.log4jdbc.DriverSpy

and adjust your database url:

Before:
jdbc:sqlserver://localhost:1433;databaseName=olabdb;

After:
jdbc:log4jdbc:sqlserver://localhost:1433;databaseName=olabdb;

Simple as that. The shadow driver of log4jdbc seems to recognize the most common SQL drivers and includes them without any effort from my side.

In order to turn logging on you add 'jdbc.sqltiming' to you log4j config in Config.groovy, e.g.
Log4j config is also explained here: http://grails.org/doc/latest/guide/conf.html#logging

Now it already works and gives you a nice and informative output including the parameters that are actually part of the SQL query. This helps a lot to learn how your domain model is reflected in the SQL world.


2012-03-08 10:58:10,515 [http-8080-5] INFO  jdbc.sqltiming  - select genes0_.recombinant_genes_id as recombin1_0_, genes0_.gene_id as gene2_0_ from gtRecombinant_gtGene
genes0_ where genes0_.recombinant_genes_id=977


My lesson was that inheritance is actually a bad thing since it causes multiple joins for each query that you do on a child class. Another thing I don't like is how hard it is to read the statements since all column names are referred to by a different name. A little more digging and I found this really nice post:

http://softdevbuilttolast.wordpress.com/2010/02/22/hibernate-sql-logging-log4jdbc-haciendo-log-de-sql-con-hibernate-log4jdbc/

It teaches you how to configure log4jdbc efficiently and to tailor it towards your needs. In my case I added a few starting parameters to my VM:

-Dlog4jdbc.debug.stack.prefix=org.openlab

This one allows you to specify your applications main package, which in turn allows log4jdbc to see where your own code begins. As a result it tells you which line of code caused the SQL query. SUPER NICE. Note that it only seems to work on log level 'all'.

Among hundreds of queries you want to see the "bad guys" that just take too long. You can set time thresholds for log.warn and log.error via

-Dlog4jdbc.sqltiming.warn.threshold=200
-Dlog4jdbc.sqltiming.error.threshold=1000

IDEA 11 and grails 1.3.7 / 2.0

Last week I gave IntelliJIDEA a shot at grails since we now have both, a new version of grails (2.0) and IDEA (11) which has a reputation for good grails support in the ultimate edition. Creating a new grails project with grails 2.0 was no problem at all. Although you have to inconveniently download and extract grails yourself, everything else works like a charm. IDEA has very good in-build support for grails, meaning you can install plugins via IDE etc. It provides a dedicated grails view for your projects and thus is offering kind of the same support as Springsource's own IDE called STS. A feature for building different kinds of grails classes is also given. What I particularly like is that you can create controller, views and tests directly via buttons offered on top of the domain class editor view. Just great :-)

But so far we haven't seen anything worth what Jetbrains charge for their software. This only becomes apparent if you use it for a little while. In the process you'll learn that code completion is by far superior to STS. IDEA always knows exactly what your domain classes look like and offers the right completion for dynamic finders à la findAllBy*. Cool stuff, but most convincing to me is actually the very good reaction time of IDEA compared to STS with mostly sluggish behaviour and an auto-update function that never worked for me. Bottom line for me was that I know decided to switch to IDEA.

For people moving from STS to IDEA, another thing will be most important. How difficult is it to move existing grails projects to IDEA? I mainly work on one project upgraded to grails 1.3.7 that involves a number of inplace-plugins. I told IDEA to create a new project from existing sources, selected the encompassing folder of all my projects and clicked next. IDEA recognized all my projects as grails/groovy projects, so I just had to select grails. Next, it asked for the SDK to use. Instead of using the 2.0 grails I added a new SDK pointing to the grails 1.3.7 folder of STS. After that, IDEA recognized all my plugins correctly (my former projects are now modules) and my application works out of the box with a normal startup (mainly thanks to using the same grails installation that already has downloaded all the necessary plugins). I was astonished how well that actually went :-)

obtain class with only short class name at hand

If you use packages in grails it's sometimes not easy to resolve a domain class, e.g. if you only have the short class name "gene" in your params when you would actually need "package.name.gene". Here is how I managed to resolve the problem:

grailsApplication.getArtefactByLogicalPropertyName("Domain", domainName.toString().toLowerCase())

how to ask user for confirmation before executing remoteLink

before:"if(!confirm('Are you sure?')) return false"

The trick is not to return "true". Credits go to this jira.

short reminder for stupid me

If the tag does not work, it is most probably because I forgot to add the braces to the variable:

never works!

usually does work!

grails and SVN

I added my grails projects to a SVN repository, in order to be able to work someplace else. When I tried to check my projects out however, they did not run.

I included .project and .classpath files as I already learned that they are needed for eclipse to recognize them as grails projects.

Problem: When I ran run-app I got error messages complaining that plugins could not be resolved (locally). Also the plugin manager in STS did not list any plugins. Nothing worked.

What I missed however was that you have to run grails upgrade to reinstantiate other missing files. Afterwards plugins are resolved correctly and downloaded from the internet. This solution was found here.