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From Clinton Begin <clinton.be...@gmail.com>
Subject Re: ResultHandler - OutOfMemory Exception
Date Tue, 13 Oct 2009 02:28:41 GMT
Okay, even though you didn't have a Jira ticket open for this, as an added
bonus of rewriting the entire result handler, there's now an optimized
implementation that should be able to handle any number of rows, as long as
you're not using nested result mapping (which makes it impossible to
avoid).
Clinton

On Tue, Sep 15, 2009 at 4:34 PM, Clinton Begin <clinton.begin@gmail.com>wrote:

> Hmmm... I don't think so. I suppose it would make sense to add that !  :-)
> Jira ticket!
>
>
> On Tue, Sep 15, 2009 at 11:57 AM, K. Arnold <akarnold@comcast.net> wrote:
>
>>
>> Out of curiosity, is it possible to create my own DefaultSetResultHandler?
>>  I
>> wrote an plugin that would intercept the call, and I was going to walk
>> through the result set myself.  Unfortunately I'm not sure how to get the
>> parameters that are used in the constructor.  Looking at the code it seems
>> to jump through some hoops passing the objects through.  Is there a
>> context
>> that contains the references to those that I could use?
>>
>>
>>
>> Clinton Begin wrote:
>> >
>> > Ah, then yes, iBATIS 3 might be more aggressive about using the nested
>> > objects cache...(even without join mapping), I can't remember if iBATIS
>> 2
>> > would behave the same way.  Might be worth a try... if it works in 2,
>> then
>> > I'll revisit the design to see if I can get 3 to only cache if it
>> detects
>> > a
>> > nested result map.
>> > Clinton
>> >
>> > On Tue, Sep 15, 2009 at 10:44 AM, K. Arnold <akarnold@comcast.net>
>> wrote:
>> >
>> >>
>> >> I have not used iBATIS 2 to do a comparison.  It is very well that the
>> >> assumption given to me about how RowHandler works is false.  I am in
>> the
>> >> process of trying to figure out a good limit size to pick utilizing an
>> >> AS400
>> >> jdbc driver working on a DB2 database.
>> >>
>> >> We have decided that utilizing the select statement with the limit is
>> the
>> >> better decision choice for us.  Now we need to figure out how to
>> optimize
>> >> it.
>> >>
>> >> Any suggestions would be appreciated :ninja:
>> >>
>> >> Just to make sure I understand your reply for any future work.  I don't
>> >> believe I am using a join mapper.  I have a POJO that maps directly to
>> a
>> >> custom (yet extremely complicated) sql statement.  The POJO doesn't
>> have
>> >> any
>> >> collections, and is basically stand alone.  It is my understanding from
>> >> your
>> >> code, that my type of POJO isn't going to utilize the join mapper
>> method,
>> >> since the next POJO will be unique.
>> >>
>> >> Clinton Begin wrote:
>> >> >
>> >> > The difference between RowHandler and ResultHandler is only in name.
>> >>  They
>> >> > did the same thing.
>> >> > I'd be interested to know if iBATIS 2.x works for you in this regard.
>> >> As
>> >> > far
>> >> > as I can recall, 2.x had the same design if you invoked the join
>> >> mapper...
>> >> >
>> >> > See, as soon as you try to use a JOIN to load a complex object graph,
>> >> we
>> >> > need to cache the results so that iBATIS knows to append to the
>> parent,
>> >> > rather than instantiate a new object.
>> >> >
>> >> > Clinton
>> >> >
>> >> > On Tue, Sep 15, 2009 at 9:04 AM, K. Arnold <akarnold@comcast.net>
>> >> wrote:
>> >> >
>> >> >>
>> >> >> Thank you for the reply.  Is it possible to make the join mapping
>> >> cache
>> >> a
>> >> >> configurable attribute on the mapping file?   This is my first
time
>> >> using
>> >> >> Ibatis and I was confidently informed that we could walk row by
row
>> >> over
>> >> >> a
>> >> >> result set.  I was told to look up the RowHandler interface.  It
is
>> my
>> >> >> understanding that in Ibatis 3 that the ResultHandler has replaced
>> the
>> >> >> RowHandler.  Was there a specific design decision made not to allow
>> a
>> >> row
>> >> >> by
>> >> >> row walk through?
>> >> >>
>> >> >> As a work around I was looking into the Plugin feature.  It looks
>> like
>> >> I
>> >> >> can
>> >> >> Intercept the resultSetsHandler method, and write my own code to
>> >> process
>> >> >> it.
>> >> >> In theory I could utilize the DefaultResultSetHandler code and
>> remove
>> >> the
>> >> >> cache feature in my implementation.  However I am not sure if I
have
>> >> >> access
>> >> >> to the same constructor parameters at the point of the intercept.
>> >> >>
>> >> >> There is some concern around the performance of also introducing
>> >> multiple
>> >> >> call backs to the Database for each "set" of data to process. 
I
>> need
>> >> to
>> >> >> balance the design choice of writing my own resultSetsHandler with
>> the
>> >> >> number of sql calls being made to the database via an offset Select
>> >> call.
>> >> >>
>> >> >> I appreciate your replies to this subject.
>> >> >>
>> >> >> Clinton Begin wrote:
>> >> >> >
>> >> >> > The nestedResultObjects is necessary for join mapping.  One
way to
>> >> deal
>> >> >> > with
>> >> >> > this though, is to use batches of reads as well as writes.
 Use
>> the
>> >> >> > pagination facilities and possibly even the proprietary
>> offset/limit
>> >> >> > features of your database to grab subsets of the results.
>> >> >> > Incidentally I'm rewriting the DefaultResultSetHandler to
be
>> easier
>> >> to
>> >> >> > understand.  But I don't see the need for that cache going
away
>> >> anytime
>> >> >> > soon...
>> >> >> >
>> >> >> > Clinton
>> >> >> >
>> >> >> > On Mon, Sep 14, 2009 at 1:47 PM, K. Arnold <akarnold@comcast.net>
>> >> >> wrote:
>> >> >> >
>> >> >> >>
>> >> >> >> I am trying to iterate over a result set of 2million records,
for
>> a
>> >> >> large
>> >> >> >> bulk load and transformation into a new ODS.  It appears
that I
>> am
>> >> >> >> getting
>> >> >> >> an OutOfMemoryException because the DefaultResultSetHandler
is
>> >> caching
>> >> >> >> the
>> >> >> >> object in the nestedResultObjects property.  Is there
some
>> property
>> >> I
>> >> >> >> should
>> >> >> >> set or statement/ method call I should be using that will
allow
>> me
>> >> to
>> >> >> >> process one line at a time and not have the nestedResultObjects
>> >> store
>> >> >> >> each
>> >> >> >> object?
>> >> >> >>
>> >> >> >> My goal:
>> >> >> >> * Grab a row
>> >> >> >> * Send it to be processed
>> >> >> >> * Once processed, move on to the next row.
>> >> >> >> Note: Once a row is processed I no longer need a tie back
to the
>> >> >> object.
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >> I have included the custom ResultHandler, the unit test
and the
>> >> >> >> configuration file.  Please let me know if you need other
>> >> information.
>> >> >> >>
>> >> >> >> package com.primetherapeutics.benplanmgr.entity.rxclaim;
>> >> >> >>
>> >> >> >> import org.apache.ibatis.executor.result.ResultContext;
>> >> >> >> import org.apache.ibatis.executor.result.ResultHandler;
>> >> >> >> import org.apache.log4j.Logger;
>> >> >> >>
>> >> >> >> /**
>> >> >> >>  * @author kjarnold
>> >> >> >>  *
>> >> >> >>  */
>> >> >> >> public class GroupEligibilityResultHandler implements
>> ResultHandler
>> >> {
>> >> >> >>        Logger logger =
>> >> >> >> Logger.getLogger(GroupEligibilityResultHandler.class);
>> >> >> >>
>> >> >> >>        int count = 0;
>> >> >> >>
>> >> >> >>        public void handleResult(ResultContext context)
{
>> >> >> >>                if(context.getResultObject() != null) {
>> >> >> >>                        count++;
>> >> >> >>                        logger.debug(count);
>> >> >> >>                }
>> >> >> >>                //context.stop();
>> >> >> >>        }
>> >> >> >>
>> >> >> >>        public int getCount() {
>> >> >> >>                return count;
>> >> >> >>        }
>> >> >> >>
>> >> >> >> }
>> >> >> >>
>> >> >> >>        @Test
>> >> >> >>        public void getGroupElibibilitiesByResultHandler()
{
>> >> >> >>                Map<String, String> parameterMap
= new
>> >> HashMap<String,
>> >> >> >> String>();
>> >> >> >>                parameterMap.put("gelThruDate", "1090101");
>> >> >> >>                parameterMap.put("addDate", "1090911");
>> >> >> >>                parameterMap.put("chgDate", "1090911");
>> >> >> >>                parameterMap.put("planDate", "1090101");
>> >> >> >>                try {
>> >> >> >>                        GroupEligibilityResultHandler handler
=
>> new
>> >> >> >> GroupEligibilityResultHandler();
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >>
>> >>
>> session.select("com.primetherapeutics.benplanmgr.entity.rxclaim.data.GroupEligibilityMapper.getGroupEligibilities",
>> >> >> >>                                        parameterMap, handler);
>> >> >> >>                        logger.debug(handler.getCount());
>> >> >> >>
>> >> >> >>                } finally {
>> >> >> >>                        session.close();
>> >> >> >>                }
>> >> >> >>
>> >> >> >>        }
>> >> >> >>
>> >> >> >>
>> >> >> >> Here are my mapping files:
>> >> >> >>
>> >> >> >> <?xml version="1.0" encoding="UTF-8" ?>
>> >> >> >> <!DOCTYPE configuration PUBLIC "-//ibatis.apache.org//DTD
Config
>> >> >> 3.0//EN"
>> >> >> >>        "http://ibatis.apache.org/dtd/ibatis-3-config.dtd">
>> >> >> >> <configuration>
>> >> >> >> <settings>
>> >> >> >>        <setting name="multipleResultSetsEnabled" value="false"/>
>> >> >> >>        <setting name="defaultExecutorType" value="BATCH"/>
>> >> >> >> </settings>
>> >> >> >>        <mappers>
>> >> >> >>                <mapper
>> >> >> >>
>> >> >> >>
>> >> >>
>> >>
>> resource="com/primetherapeutics/benplanmgr/entity/rxclaim/data/BenefitMaxSchedule.xml"/>
>> >> >> >>                <mapper
>> >> >> >>
>> >> >> >>
>> >> >>
>> >>
>> resource="com/primetherapeutics/benplanmgr/entity/rxclaim/data/GroupEligibility.xml"/>
>> >> >> >>        </mappers>
>> >> >> >> </configuration>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >> --
>> >> >> >> View this message in context:
>> >> >> >>
>> >> >>
>> >>
>> http://www.nabble.com/ResultHandler---OutOfMemory-Exception-tp25442025p25442025.html
>> >> >> >> Sent from the iBATIS - User - Java mailing list archive
at
>> >> Nabble.com.
>> >> >> >>
>> >> >> >>
>> >> >> >>
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>> >> >> >> For additional commands, e-mail:
>> user-java-help@ibatis.apache.org
>> >> >> >>
>> >> >> >>
>> >> >> >
>> >> >> >
>> >> >>
>> >> >> --
>> >> >> View this message in context:
>> >> >>
>> >>
>> http://www.nabble.com/ResultHandler---OutOfMemory-Exception-tp25442025p25455710.html
>> >> >> Sent from the iBATIS - User - Java mailing list archive at
>> Nabble.com.
>> >> >>
>> >> >>
>> >> >>
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>> >> >>
>> >> >>
>> >> >
>> >> >
>> >>
>> >> --
>> >> View this message in context:
>> >>
>> http://www.nabble.com/ResultHandler---OutOfMemory-Exception-tp25442025p25457565.html
>> >> Sent from the iBATIS - User - Java mailing list archive at Nabble.com.
>> >>
>> >>
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>> >>
>> >>
>> >
>> >
>>
>> --
>> View this message in context:
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>> Sent from the iBATIS - User - Java mailing list archive at Nabble.com.
>>
>>
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>

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