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https://issues.apache.org/jira/browse/OOZIE-3409?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16726008#comment-16726008
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Praneeth edited comment on OOZIE-3409 at 12/20/18 4:46 PM:
-----------------------------------------------------------

Actually, I don't think it is just the actions that have EL expressions that 
sit in the cache, I think the parsing is taking place for every action (or some 
part of workflow config), whether or not it has an EL (call to parsing takes 
place irrespectively) [1]. If it doesn't have an EL, the cache would store the 
same content as both key and value. I was able to verify this by looking at the 
contents of the cache.

This is only to point out that it is not just for EL based content. I do not 
have a good proposal for a solution given the dependency is dormant. What is 
the general practice for fixes to dormant projects ? Is it to try to find an 
alternative and if none is found, try to revive the project ?

I agree that it is probably a problem to few deployments like ours which are 
long running and relatively large workflows, but this crashes our instances 
once in 2-3 months.

 
 # I was checking the usage of 
[https://github.com/apache/oozie/blob/master/core/src/main/java/org/apache/oozie/util/ELEvaluator.java#L201.]


was (Author: praneeth.varma):
Actually, I don't think it is just the actions that have EL expressions that 
sit in the cache, I think the parsing is taking place for every action (or some 
part of workflow config), whether or not it has an EL (call to parsing takes 
place irrespectively) [1]. If it doesn't have an EL, the cache would store the 
same content as both key and value. I was able to verify this by looking at the 
contents of the cache.

This is only to point out that it is not just for EL based content. I do not 
have a good proposal for a solution given the dependency is dormant. What is 
the general practice for fixes to dormant projects ? Is it to try to find an 
alternative and if none is found, try to revive the project ?

I agree that it is probably a problem to few deployments like ours which are 
long running and relatively workflows, but this crashes our instances once in 
2-3 months.

 
 # I was checking the usage of 
[https://github.com/apache/oozie/blob/master/core/src/main/java/org/apache/oozie/util/ELEvaluator.java#L201.]

> Oozie Server : Possible memory leak in EL evaluation
> ----------------------------------------------------
>
>                 Key: OOZIE-3409
>                 URL: https://issues.apache.org/jira/browse/OOZIE-3409
>             Project: Oozie
>          Issue Type: Bug
>    Affects Versions: 5.1.0
>            Reporter: Praneeth
>            Priority: Major
>
> I have noticed that there is a potential memory leak in the Oozie server due 
> to one of its dependencies - {{commons-el:commons-el:1.0}}. Our oozie servers 
> have been running out of memory occasionally. It happens more often when we 
> have more activity. Upon analysis of the heap dump, it seems that the culprit 
> here is the {{org.apache.commons.el.ExpressionEvaluatorImpl}} from 
> {{commons-el}} which is used in the Oozie server through 
> {{org.apache.oozie.util.ELEvaluator}} [1] . {{ExpressionEvaluatorImpl}} uses 
> a static {{Map}} [2] to cache the EL evaluations. This map never gets 
> cleared, eventually taking up all the memory. So, in an environment with 
> heavy usage and long running oozie servers, this would lead to an OOM. The 
> configurations for workflow actions we have are possibly larger than normal 
> which is worsening the situation as the Map has to maintain larger strings.
>  # 
> [https://github.com/apache/oozie/blob/release-5.1.0/core/src/main/java/org/apache/oozie/util/ELEvaluator.java#L143]
>  # 
> [http://svn.apache.org/viewvc/commons/dormant/el/trunk/src/java/org/apache/commons/el/ExpressionEvaluatorImpl.java?view=markup#l94]



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