https://bz.apache.org/bugzilla/show_bug.cgi?id=58328
Bug ID: 58328
Summary: Very slow rendering time when there are undefined el
variables - no caching in ImportHandler
Product: Tomcat 8
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: regression
Priority: P2
Component: EL
Assignee: [email protected]
Reporter: [email protected]
Created attachment 33062
--> https://bz.apache.org/bugzilla/attachment.cgi?id=33062&action=edit
Sample page showing the problem
As it says in https://tomcat.apache.org/migration-8.html#JavaServer_Pages_2.3
static fields can be used in expressions. The problem is that every undefined
variable in such expression is checked agains configured set of packages due to
lack of caching this lookup is performed on every request. Class that performs
the lookup is the javax.el.ImportHandler
http://svn.apache.org/viewvc/tomcat/tc8.0.x/trunk/java/javax/el/ImportHandler.java?view=markup
. It has clazzes and statics variables, their initialization suggest that they
could be used in multithreaded environment yet ImportHandler is constructed
every time new ELContext is created (and if I understand correctly this is done
in context of a single page request thus it's executed by single thread).
I think that fields clazzes and statics should be static.
To reproduce this issue:
1. Get Tomcat, unpack and start it
2. Take attached jsp page and put it on ie to webapps/ROOT
3. Use tool like siege ( https://www.joedog.org/siege-home/ ) to test the
performance:
siege http://localhost:8080/heavyPage.jsp -c 1 -d 0 -t 10s
My results are pasted below (Tomcat7, Tomcat8, and Tomcat8 with
ImportHandler.clazzes and ImportHandler.statics changed to static).
Apache Tomcat 7.0.64:
Transactions: 6938 hits
Availability: 100.00 %
Elapsed time: 9.41 secs
Data transferred: 16.03 MB
Response time: 0.00 secs
Transaction rate: 737.30 trans/sec
Throughput: 1.70 MB/sec
Concurrency: 0.97
Successful transactions: 6938
Failed transactions: 0
Longest transaction: 0.03
Shortest transaction: 0.00
Apache Tomcat 8.0.26:
Transactions: 7 hits
Availability: 100.00 %
Elapsed time: 9.14 secs
Data transferred: 0.02 MB
Response time: 1.27 secs
Transaction rate: 0.77 trans/sec
Throughput: 0.00 MB/sec
Concurrency: 0.97
Successful transactions: 7
Failed transactions: 0
Longest transaction: 1.36
Shortest transaction: 1.22
Apache Tomcat - trunk version with suggested fix:
Transactions: 5786 hits
Availability: 100.00 %
Elapsed time: 9.93 secs
Data transferred: 13.36 MB
Response time: 0.00 secs
Transaction rate: 582.68 trans/sec
Throughput: 1.35 MB/sec
Concurrency: 0.97
Successful transactions: 5786
Failed transactions: 0
Longest transaction: 0.02
Shortest transaction: 0.00
Best,
Janusz
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