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From is_maximum <mnr...@gmail.com>
Subject Re: [URGENT] performance issues
Date Wed, 28 Jan 2009 18:13:18 GMT

Hi Kevin
Thanks for your reply

>>How are you invoking the enhancer?
First I tried to set the javaagent in my App server but there was a
NoClassDefFoundError so I leave it out and in OpenJPA manual I found that
the enhancer in Java EE 5 will be automatically enabled. Thus actually I am
relying on App server. and container-managed persistence 

>>The methods that you mention below are very minor, from a processing
viewpoint.
each call is minor but when I see the JProbe reports it shows that a single
save() method in which we used em.persist() have taken say 200000 millis and
almost 60 percent of this time is taken cumulatively by methods used by
enhancer rather than the call to persist() method.


>>Are your Entities "versioned"?
No. Actually we don't use optimistic locking purposely because the number of
update to the records are really high and also the number of requests is
really high as well. Let me tell you this is a banking system and this
business method we are testing is one of the critical methods that supposed
to have high performance. By optimistic locking, all other requests will
face problem and we need to ask the users to retry their request and neither
the users nor the bank managers will accept this.

>>Are you using Lazy or Eager fetching of attributes and relationships?
well generally we are using lazy relationships but in this specific case, we
don't need any eager fetching and the entities are single fortunately.

>>I see in your persistence.xml that you have turned off statement batching
for your Oracle database
Well I didn't get attention to it and I'll ask my colleagues in the team if
they had any reason to turn it off.

>>And, turning on the data cache should also help, not cause you to go
backwards.  You do mention that you are using the 1.2.0 release.  Have you
tried moving to a later revision in the 1.2.x service stream?  Or, even the
1.3.x branch?  Just to help narrow down whether something has already been
discovered and resolved for your environment.

No I didn't try later versions and yes I have to test it
But regarding the data cache, I am wondered why using that we got lower
performance!!!
We set the data cache with a size of 2000 and soft cache enabled with a size
of 100. However I am a bit scared of getting unusual results using data
cache due to frequent update we make into the tables.

finally I appreciate your reply and trying to help me. thanks


Kevin Sutter wrote:
> 
> Hi is_maximum,
> The results you are experiencing are atypical.  Normally, when the Entity
> classes are enhanced, OpenJPA's performance is one of or the best,
> depending
> on the specific benchmark.  Let's start with a few questions to see if we
> can narrow in on the problem.
> 
> o  First off, you mention the enhancer.  How are you invoking the
> enhancer?
> Are you statically pre-enhancing the Entity classes?  Or, are you using
> the
> -javaagent jvm parameter?  Or, are you relying on the Container
> classloader
> integration?  I see that you are using the Sun Application Server, but are
> you relying on the container-managed persistence or are you using
> application-managed persistence?
> 
> o  The methods that you mention below are very minor, from a processing
> viewpoint.  So, I really don't think the slow-down is due to enhancement.
> 
> o  Are your Entities "versioned"?  That is, are you using an @Version
> field
> in your Entities?  Due to the optimistic locking that JPA does by default,
> determining whether a given Entity is different from the database contents
> is much, much more efficient if we can just check the @Version field
> instead
> of comparing all of the individual fields.
> 
> o  Are you using Lazy or Eager fetching of attributes and relationships?
> Depending on the type of the attribute and/or relationship, the default
> fetch type may be different.  For example, if you have a relationship
> defined as having a Lazy fetch type, but you are constantly accessed the
> contents of that relationship, then instead of waiting until you touch
> that
> relationship to get the contents from the database (lazy), you should
> probably change that to eager to allow us to get the data on the first
> trip
> to the database.  The default values for the fetch type are meant to fit
> the
> 80/20 rule, but depending on your application, they may not fit your
> needs.
> 
> o  I see in your persistence.xml that you have turned off statement
> batching
> for your Oracle database.  That's kind of surprising since under normal
> circumstances, statement batching can only help your performance concerns.
> Unless you are hitting some condition that forced you to turn it off?
> 
> o  And, turning on the data cache should also help, not cause you to go
> backwards.  You do mention that you are using the 1.2.0 release.  Have you
> tried moving to a later revision in the 1.2.x service stream?  Or, even
> the
> 1.3.x branch?  Just to help narrow down whether something has already been
> discovered and resolved for your environment.
> 
> Let's start with that and see where these questions and answers take us.
> 
> Kevin
> 
> On Wed, Jan 28, 2009 at 7:41 AM, is_maximum <mnrz57@gmail.com> wrote:
> 
>>
>> Hi
>>
>> We have a big problem in performance. We are using JProbe to inspect what
>> happens in our code and there is a critical business method which is
>> required to have a high TPS but unfortunately this method is doing its
>> job
>> really slow.
>>
>> Using JProbe, we found out that in a simple query or persist methods
>> (merger() / persist()...) those methods related to OpenJPA's enhancer
>> such
>> as pcReplaceField(int), pcNewInstance() and generally pc* methods have
>> long
>> duration in compare to our methods.
>>
>> As I read in OpenJPA manual the enhancer is engaged to obtain higher
>> performnce but in action we see a different result.
>>
>> Do we missed something that make enhancer not work properly or is there
>> anything else we should consider?
>>
>> I also enabled the data caching but strangely the performance has been
>> decreased!!!
>>
>> Please share your exprience with me.
>>
>> OpenJPA 1.2.0
>> Sun Java Application Server 9.1
>>
>> -----
>>
>> persistence.xml
>>
>>            <property name="openjpa.jdbc.DBDictionary"
>> value="oracle(batchLimit=0)"/>
>>            <property name="openjpa.jdbc.SubclassFetchMode" value="join"/>
>> -->
>>            <property name="openjpa.jdbc.SynchronizeMappings"
>>
>> value="buildSchema(foreignKeys=true,schemaAction='none')"/>
>>
>>            <property name="openjpa.jdbc.MappingDefaults"
>>
>>
>> value="ForeignKeyDeleteAction=restrict,JoinForeignKeyDeleteAction=restrict"/>
>>           <property name="openjpa.RestoreState" value="all"/>
>>
>>
>> --
>> View this message in context:
>> http://n2.nabble.com/-URGENT--performance-issues-tp2232295p2232295.html
>> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>>
>>
> 
> 

-- 
View this message in context: http://n2.nabble.com/-URGENT--performance-issues-tp2232295p2233824.html
Sent from the OpenJPA Users mailing list archive at Nabble.com.


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