[MYFACES-3586] Performance improvement in Resource loading - HIGH CPU inflating bytes in ResourceHandlerImpl.handleResourceRequest

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.1.11
• Environment: ALL
• Assignee: Leonardo Uribe
• Reporter: Rohit Dilip Kelapure
• Created: 19/Jul/12 14:45
• Updated: 28/Mar/13 16:00
• Resolved: 27/Mar/13 22:21

Description

In a high concurrency load test with Apache MyFaces + RichFaces component library we found that under peak load majority of our web container threads were stuck in this call stack

at java/util/zip/Inflater.inflateBytes(Native Method)
at java/util/zip/Inflater.inflate(Inflater.java:249(Compiled Code))
at java/util/zip/InflaterInputStream.read(InflaterInputStream.java:146(Compiled Code))
at java/util/zip/InflaterInputStream.read(InflaterInputStream.java:116(Compiled Code))
at java/io/FilterInputStream.read(FilterInputStream.java:77(Compiled Code))
at java/io/FilterInputStream.read(FilterInputStream.java:77(Compiled Code))
at java/io/PushbackInputStream.read(PushbackInputStream.java:133(Compiled Code))
at org/apache/myfaces/shared_impl/resource/ResourceImpl$ValueExpressionFilterInputStream.read(ResourceImpl.java:117(Compiled Code))
at java/io/InputStream.read(InputStream.java:175(Compiled Code))
at java/io/InputStream.read(InputStream.java:97(Compiled Code))
at org/apache/myfaces/application/ResourceHandlerImpl.pipeBytes(ResourceHandlerImpl.java:402(Compiled Code))
at org/apache/myfaces/application/ResourceHandlerImpl.handleResourceRequest(ResourceHandlerImpl.java:357(Compiled Code))
at org/richfaces/resource/ResourceHandlerImpl.handleResourceRequest(ResourceHandlerImpl.java:257(Compiled Code))
at javax/faces/webapp/FacesServlet.service(FacesServlet.java:183(Compiled Code))
at org/richfaces/webapp/ResourceServlet.httpService(ResourceServlet.java:110(Compiled Code))
at org/richfaces/webapp/ResourceServlet.service(ResourceServlet.java:105(Compiled Code))

After looking at the src code of org.apache.myfaces.application.ResourceHandlerImpl.handleResourceRequest(FacesContext) I can see that the ResourceHandlerCache caches the Resource metadata ; however the actual output of the resource which is written to the outputstream in ResourceHandlerImpl.pipeBytes is NEVER cached.

This causes a scalability problem in our case because each access to the resource involves cracking open a jar, inflating the bytes and parsing a stream of bytes. This is done multiple times for the same resource(say a css file) inside the richfaces jar inspite of the resource not changing.

I propose a much needed performance optimization wherein we cache the output of the Resource handled and stash the output byte[] it as softReference in the ResourceHandlerCache.ResourceValue.