[WW-4485] New cacheKey is too expensive to create

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 2.3.28, 2.5
• Component/s: Core Actions, Expression Language
• Labels: ognl
• Assignee: Lukasz Lenart
• Reporter: Jasper Rosenberg
• Created: 06/Apr/15 21:33
• Updated: 29/Mar/16 10:14
• Resolved: 07/Apr/15 10:41

Description

So we pushed ognl 3.0.10 to production this afternoon, and promptly had to rollback because load on the servers went through the roof. Looking at the stack traces, the issue was tons of threads doing this:

      at java.lang.Class.getEnclosingMethod0(Native Method)
      at java.lang.Class.getEnclosingMethodInfo(Class.java:1059)
      at java.lang.Class.isLocalOrAnonymousClass(Class.java:1449)
      at java.lang.Class.getCanonicalName(Class.java:1377)
      at ognl.OgnlRuntime.buildCacheKey(OgnlRuntime.java:1944)
      at ognl.OgnlRuntime.getGetMethod(OgnlRuntime.java:1926)
      at ognl.OgnlRuntime.hasGetMethod(OgnlRuntime.java:1985)
      at ognl.OgnlRuntime.hasGetProperty(OgnlRuntime.java:2045)
      at com.opensymphony.xwork2.ognl.accessor.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:141)

The problem is that the change to buildCacheKey() for https://issues.apache.org/jira/browse/WW-4113 is way to expensive considering how often it is called.

I'd like to suggest replacing the current buildCacheKey() implementation with this:

    private static Object buildCacheKey(Class targetClass, String propertyName) {
        return new CacheKey(targetClass, propertyName);
    }
    
    private static final class CacheKey {
        private final Class clazz;
        private final String propertyName;

        public CacheKey(Class clazz, String propertyName) {
            this.clazz = clazz;
            this.propertyName = propertyName;
        }
        
        public boolean equals(Object obj) {
            CacheKey cacheKey = (CacheKey) obj;
            return clazz.equals(cacheKey.clazz)
                && propertyName.equals(cacheKey.propertyName);
        }
        
        public int hashCode() {
            return clazz.hashCode() * 31 + propertyName.hashCode();
        }
    }

Issue Links

• is broken by: WW-4113 Wrong cache key generated in OGNL 3.0.5/3.0.6