[D'Espice]

Hi,

I wrote a Java application for small and medium sized hotels and found out, that it's terribly slow on Macs for some reason. The app loads a reservation table via FileInputStream/ObjectInputStream which contains an ArrayList of String[100000] for each room. For 34 rooms it takes about 3s to load on my Opteron, about 5s on the P4/1.8 GHz at work yet several minutes on a G4/867 running OS X 10.3 with the latest Apple Java MRJ.

I had to create a special Mac Version with only 20,000 entries for each room which however is still unbearably slow. Less than 1s on my Opteron, 1-2s on the P4 yet almost 17s on a G4. I assume that Apple's Java Implementation is just, well, awful. Is there any workaround that will NOT require me to switch to RandomFileAccess or make me decrease the database size to less than 10000 entries per room?

You can check it out for yourselves, download v. 0.62 from http://sourceforge.net/projects/jhotel. That's the version with 100,000 entries per room and completely unusable on Macs. If you want the version with 20,000 entries per room (v 0.62.1) which I do not intend to publish on SF, email/pm me and I'll send it to you via email.

[Arkham_c]

How do I run it to test the I/O?

A few observations:

1) All those internal classes -- yuck!
2) Consider an ant build script
3) setNextFocusableComponent(java.awt.Component) in javax.swing.JComponent has been deprecated
4) Have you considered package management? 32 source files in the default package.

[thefamousmred]

Originally posted by D'Espice:
Hi,

I wrote a Java application for small and medium sized hotels and found out, that it's terribly slow on Macs for some reason. The app loads a reservation table via FileInputStream/ObjectInputStream which contains an ArrayList of String[100000] for each room. For 34 rooms it takes about 3s to load on my Opteron, about 5s on the P4/1.8 GHz at work yet several minutes on a G4/867 running OS X 10.3 with the latest Apple Java MRJ.

This isn't much more than a wild-assed guess, but from looking at your code and the results I'd say it's a buffering problem. You creat ObjectInputStreams with a FileInputStream; any object you read from the OIS will result in one or more calls to the FIS. Since the FIS isn't buffered by default, that will result in a disk access for each read call. Disk access is very slow, and should be avoided whenever possible. My guess is that this performs fine on Windows because Windows systems buffer file access at the OS level, whereas OS X won't necessarily do that.

To fix performance, try wrapping the FileInputStream in a BufferedInputStream, and pass the BIS to the ObjectInputStream constructor:

FileInputStream fis = new FileInputStream("./db/restable.jh");
BufferedInputStreambfis = new BufferedInputStream(fis);
ObjectInputStream ois = new ObjectInputStream(fbs);

The BufferedInputStream will read a chunk of data from the FileInputStream, and use that to service requests from the ObjectInputStream. Once the buffer runs out, the BIS will read another chunk from the FIS. This should dramatically reduce the number of disk reads, speeding up the app. For even more performance you can experiment with different buffer sizes in the BIS constructor.

[D'Espice]

Hmm... that sounds interesting, I'm gonna give that a shot, thanks.

@Arkham_c

I run the test by simply opening the reservation management window. I know that it's deprecated but it's working, I'm gonna take care of that as soon as it stops working
And about those internal classes, how would you do it? I tried to split it up into as many source files as possibe cause IMHO several small files/classes are better than a huge one.