items tagged with tuning

Still not enough, we were forced to profile the java code and make some big changes.... (from part 1)

Profiling

You either profile an application for speed and/or memory usage and/or memory leaks. Our application is fast enough at the moment. Our major concern is optimizing memory usage and thus avoiding disk memory swapping.

Some words about architecture

It is not possible to profile any applications without having a deep understanding of the architecture behind. The Product Catalog is an innovative product which is a meta model for storing insurances product in a database, a Product is read only and  can derivate instance that we call Policies. Policies are users data holder, containing no text, just values, and sharing a similar structure as the Product. This let the product know everything about (cross) default values, (cross) validations,  multiple texts, attributes order/length/type etc... and thus separate definition (Products) from implementation (Policies). Products and Policies can be fully described  with Bricks, Attributes in a tree manner.

Reduce the number of object created

Looking at the code, we have seen that too many Products (17 Products has 15000 objects either Attributes/Bricks/Texts/Value/ValueRange) were loaded in memory. While this is clearly giving a speed advantage on an application server, it is simply killing the offline platform with it 1GB RAM (remember memory really free is 500Mb)
The problem is that Attributes and Brick are using/can use  a lot of fields/meta data in the database which translate into simple java type (String for UUID, and meta data keys and values) in  memory. We start looking at the profiler and the 100 MB used by the product cache.
Reducing this amount of object was the first priority, a lot of them are meta data which are common and spread across the Product Tree in memory. Since avoiding creation of unneeded object is always recommended, we decide to remove duplicate element in the tree by singularizing them. This is possible because the product is Read Only and made of identical meta data keys, meta keys value.

We are working since 3 days on tuning a big application: 

• Client server enterprise grade application,
• Run on 2 JVM  with 4Gb (Tomcat/Application server) of RAM each!
• Run on 2 Double core AMD 64 bits server,
• Linux 64bits,
• Has a lot of parallel users and > 10000 are registered
• Use a product meta model which separate definition from implementation data.
• Java server faces, java, ajax

• The same code as above,
• In windows XP, 
• IBM T40,  Intel Pentium M 1.6 GHz,  DDR266/PC2100
• 1 JVM with 500Mb in Tomcat,
• 1 GB of physical Ram,
• 1 Desktop user who may run also Lotus Notes, Microsoft Office at the same time...