Zoly's Blog

As expected work is in progress to replace Linux as the OS building block in Oracle's Database Machines:

http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6965606

Optimizations are being done for a "solexadata_demo"

Nice to see Linux being replaced by the best OS :-)

With the new generation of developers I increasingly see less desire of writing efficient code. It also makes me quite angry when I hear arguments like "disk is cheap", "memory is cheap", ... "premature optimization is evil".

Writing code is a difficult task, it is a continuous balancing between implementation choices,  but writing a efficient implementation is not always hard and time consuming.

I will give a small, recent example:

I recently spent 10 minutes of my time to optimize a data cache component that was taking up 250 Mb of RAM, and reduced the memory usage by 150Mb. Since this optimization was on a component that was reused in several processes my 10 minutes spent became even more valuable. All I did I internalized the string attributes that were highly redundant.

By reducing the amount of memory my application uses, I also increased the performance:

Less GC overhead, higher CPU cache hit ratios, less interconnect utilization (NUMA), more memory available to the disk cache, less process swapping.

One of the metrics you can monitor is:  "cycles per instruction"  (how to measure: http://blogs.sun.com/brendan/entry/amd64_pics). This metric can improve significantly by reducing your memory footprint.

Conclusion: Using String.intern is a simple and efficient way of optimizing your implementation.

My "favorite" part of the brochure: "the ideal server to refresh inefficient and outdated HP Itanium and IBM Power servers." 

They also forgot to mention that the servers are unbreakable :-)

When embedding ZEL the implementation of the Floating point numbers can be chosen as:

ExtendedMathContext.DECIMAL64_MATHCONTEXT

ExtendedMathContext.DECIMAL128_MATHCONTEXT 

ExtendedMathContext.DOUBLE64_MATHCONTEXT

ExtendedMathContext.NATIVE.GNUFLOAT128_MATHCONTEXT 

ExtendedMathContext.NATIVE.GNUFLOAT256_MATHCONTEXT 

ExtendedMathContext.NATIVE.GNUFLOAT512_MATHCONTEXT  

A few days of bad wether and the ZEL language gets some significant enhancements:

Deterministic functions:

Q: What is a deterministic function?

A: A funtion that always returns the same value, for the same parameters.

How do we define a deterministic function:

fib= lambda deterministic (x) { fib( x-1) + fib( x-2); };

fib(0)=0; fib(1)=1;

You can find more info here:

http://blogs.sun.com/bonwick/

Congrats to jeff & co.

One more reason to use opensolaris for your file serving needs. If you want to build your own here is a good example:

http://blogs.sun.com/mebius/entry/diy_home_nas_box_with2

Today's latest trend is going Green, everybody is talking about reducing it's carbon footprint, we have Green cars, Green Buildings, Green Data Centers,.....

The major hardware vendors battle each other on who makes the most energy efficient hardware, and some electricity utility companies even offer rebates for using energy efficient hardware (ex: Sun's UltraSparc T1). 

One day, I wanted to get my MS Project tasks into MS Outlook, here is how I did it:

http://geekswithblogs.net/nestor/archive/2006/12/29/102260.aspx

There is no secret that I am a big Solaris fan. For me as a developer ZFS and DTrace changed my life, improoving my productivity significantly. With ZFS and its snapshoting/cloning capabilities, I have no fear in doing experiments and I can always go back in time and recover in case something goes wrong. On the other hand DTrace with D-Light allows you to look inside your running application.

If you want to learn more there is an excellent tutorial that describes how to use DLight to profile your applications:

http://developers.sun.com/sunstudio/documentation/tutorials/d_light_tutorial/index.html

My server, as every member of my family recently moved to Jersey City, so I i finally  was forced to configure vnc on it to be able to do my unix work.

The Xwin redirect does not work as well as VNC even on my local network...

found this useful blog that assisted me:

http://blogs.sun.com/scf/entry/vnc_setup_on_open_solaris

I have added support for lambda expressions in ZEL, also added a FOR statement that can iterate all variables that match a wildcard and apply a lambda function to it.

abc=1;

afe=2;

bfa =3;

x=0;

result=for("`a*`",lambda(x=x+arg(0);));

print x; // x will be 3

Functions are objects, so you can do, and apply using the () operator:

x = lambda(return arg(1)+arg(0);); z= x(1,2); print z;  //will return 3

In my projects I am required to switch back and forth from C++ and Java.

The typical reason for using C++ is performance and tight integration with OS/Hardware (ex: process management).

The typical reason for using Java is coding speed and portability.

One of the major barriers  that I encounter in my development work  is how software is organized in C++ vs Java, at this chapter java is arguably better than the classic  C++ way. (the hpp/cpp separation is evil :-) )

I found an interesting article about how C++ code can be organized in a more Java like way:

http://strlen.com/rants/javaclassesincpp.html

Now I think this might work if you create "modules" (groups of classes) ....

Last few weeks, the technology news were dominated by the IBM and SUN merger rumors. I went on to do some reading on Sun blogs and found:

 Jonathan's opinion about IBM - Redhat relationship: http://blogs.sun.com/jonathan/entry/ibm_is_in_a_pickle

I also found a simple and funny comparison between IBM and SUN cultures done by a Sun employee:

http://blogs.sun.com/gameguy/entry/sex_at_ibm_and_sun

I have contributed a Maven 2 plugin for the pldoc project, the plugin is also available in the central repository.

One excuse less to document your PLSQL code.

Sometimes you have a reporting application running reports on a oracle database. Your oracle database might consolidate data from quite a few mysql databases (via ETL). However some detail data remains always on the mysql databases. Of course the day will come when the reporting application will need the ability to drill down to the detail data from the mysql databases.

That day you will read up on Oracle Heterogeneous Data Access, ODBC, Mysql Proxy...

In case you need only read access to the mysql databases,  you might not feel like dealing with licensing for Oracle Heterogeneous Data Access via ODBC or Mysql protocol manipulation in LEA. Here is what you might want to do:

Use oracle table functions implemented in java to access your mysql tables via JDBC and your queries might look like:

select * from table (typeName_FT('SELECT * FROM remoteTable where condition' ,'jdbc:mysql://host:port/database', 'user', 'password', timeout,'typeName'));

(to create typeName_FT table function you need to call createSqlObjects defined in the code that follows)

To write a java stored procedure is straight forward, use your favorite IDE, make sure your JVM is same version with the Oracle JVM, after you are done, load your jar[s] with:

loadjava -thin -user user/password@localhost:1521:[sid] -resolve -verbose {path}/*.jar

your java stored procedures/functions are nothing else than java static functions, however for you to access them from plsql you need to create a PLSQL call wrapper:

   CREATE OR REPLACE PROCEDURE createSqlObjects( p1 IN VARCHAR2,
      p2 IN VARCHAR2,
      p3 IN VARCHAR2,
      p4 IN VARCHAR2,
      p5 IN VARCHAR2)
      RETURN VARCHAR2 AS
      LANGUAGE JAVA NAME 'mypack.JDBCUtil.createSqlObjects(java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.lang.String)';
 

Here is the java source you need for my sql example:

Got a new "workstation" from Dell, a XPS 730 with the new Core I7 cpu and DDR3 memory. (the usual with Dell, you always feel funny when you buy from them with their confusing deals and coupons...)

This machine is basically a gaming machine, but I thought that opensolaris would not complain about it ...

Hmm, instalation was far from painless...

the following parts were not recognized out of the box:

1. Nvidia gforce 9800 GTS

2. Broadcom Netlink BCM5784M Gigabit Ethernet

3. Creative Labs Sound Blaster XFI

the video card problem I resolved with help from the xwin-discuss mailing list:

# update_drv -a -i '"pci10de,605"' nvidia
# reboot

The sound card I have attempted to resolve with oss, however the sbxfi driver provided is beta and looks like it does not recognize my card... I have posted my issue on the driver-discuss mailing list ... hope that a future update will resolve the issue.

UPDATE: I have removed the plastics that were covering the onboard audio, removed the creative card and activated in BIOS the onboard audio and I have some bad quality sound on my system right now, better than nosound.

Sun's project boomer will redo the Sun audio and marry it with the open sound system, expected delivery will be in snv_115, meanwhile I am working with the beta code from http://www.opensolaris.org/os/project/opensound/files/

The Network card issue I temporarily resolved by installing a pci network card that was recognized by opensolaris. Meanwhile a RFE has been filled: http://bugs.opensolaris.org/view_bug.do?bug_id=6786742   it does not look like too much priority is given to desktop cards by Broadcom, well I will have to go ahead and purchase a card from their competitors...

JBoss Rules is one of the best open source rules engines available to integrate inside your application (for more information on features: http://www.jboss.org/drools/).

JBoss Rules provides both a Rule Engine and a Rule Management System (Guvnor).

1. Integrating the Rule Management System UI.

Guvnor is a web based jbrms that allows you to create, test, deploy your rules and a lot more. It uses Apache Jackrabit to persist the rules, Apache Jackrabbit is a fully conforming implementation of the Content Repository for Java Technology API (JCR). here is how your J2EE app will look like:

 You will need to create an war maven 2 project that will overlay the guvnor war, and allow you to customize rules persistence and integrate security, for this you will only need to customize components.xml located in WEB-INF.

here is how your pom.xml will look like:

in src/war you will add your version of components.xml (based on the one from the guvnor war).

in your pom.xml from your application ear you will add your guvnor overlay web module:

                        <webModule>
                            <artifactId>my-guvnor</artifactId>
                            <groupId>my-apps</groupId>
                            <contextRoot>rules</contextRoot>
                        </webModule>

You will also need to add some menu item or buttons to jump to your new BRMS GUI from your app and you have a brand spanking new gui module in your app.

2. Integrating the Rule Engine:

create a rule agent:

agent = RuleAgent.newRuleAgent("/rules.properties");

where rules.properties can be:

newInstance=true
localCacheDir=/tmp
url=http://localhost:8080/rules/org.drools.guvnor.Guvnor/package/com.mycompany.myapp/production
poll=30
name=myrules

the RuleAgent will poll for rules at the provided url (where your BRMS GUI will publish them).

Create a statefull engine session, assert your facts and fire your rules:

And enjoy troubleshooting and debugging the new world of declarative programming issues that are in my view not any easier to debug...

I upgraded to snv101a and to my surprise a feature called Time Slider was available.

The implementation is quite nice, in nautilus you have a time line slider that you activate pushing the new time buton in the toolbar, you slide to the desired point in time right click on the file/folder you want to recover and select restore to desktop ...

Finally a rainy day to give me some time to update my workstation/server to a newer release of opensolaris. 

This is why:

1. ZFS everywhere,  I used to have UFS, with 2 alternate boot environments. With ZFS I will have more flexibility in my experiments (snapshots to rollback in case something will go wrong, clones for test environments), it is so easy with ZFS...

2. IPS for the easier updates and installs.

3. Up to date desktop environment.

Since I started writing java applications about 10 years ago I saw quite a few OOMs, today I had the honor to see a new one:

java.lang.OutOfMemoryError: GC overhead limit exceeded

Hmm, so if the garbage collector is running like crazy (98% of the time) then the jvm will throw a OOM. This seems to be a feature of the paralel GC ...

I see a lot of java code every day with code that does Exception handling in non-conventional ways (download jboss or glassfish sources and take a look and see the aboundance of catch(Throwable)). Here is my opinion about theese practices and it is pretty much in line with the java documentation.