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From "Kim Horn" <kim.h...@icsglobal.net>
Subject RE: VFS - Synapse Memory Leak
Date Fri, 20 Mar 2009 00:41:17 GMT
Not really; I cannot see why memory should permanently grow when I pass the same file
repeatedly through VFS. In theory this means VFS will always consume all the available memory
given enough time and file iterations. Therefore VFS cannot be used in a production system.
This is definition of Memory Leak. I would expect SOME overhead on top of file size but
I would assume the memory no longer required would be re-claimed. I would also assume
The overhead was not 10 times the file size; seems excessive.

Yes I understand the streaming approach should in theory use a fixed and much smaller amount
of memory;
but haven't tested that yet either. No reason given above memory leak that it should not permanently
grow
but at a smaller rate aswell.

Thanks 
Kim

-----Original Message-----
From: Andreas Veithen [mailto:andreas.veithen@gmail.com] 
Sent: Friday, 20 March 2009 10:52 AM
To: dev@synapse.apache.org
Subject: Re: VFS - Synapse Memory Leak

If N is the size of the file, the memory consumption caused by the
transport is O(N) with transport.vfs.Streaming=false and O(1) with
transport.vfs.Streaming=true. The getTextAsStream and writeTextTo
methods in org.apache.axis2.format.ElementHelper are there to allow
you to implement your mediator with O(1) memory usage, so that the
overall memory consumption remains O(1). Does that answer your
question?

Andreas

On Thu, Mar 19, 2009 at 23:33, Kim Horn <kim.horn@icsglobal.net> wrote:
> It's the same Synapse.xml as specified originally and same trace. If you are using Nabble
you can see this, in case you lost the prior emails I can post them again.
>
> I must admit I did not set those extra parameters, you mentioned, but I don't see why
you should set parameter to Stop a memory leak. I guessed these parameter would just reduce
the large amounts of memory it appears to be using, e.g. 10 times the file size, via streaming
? Why is their 10 copies of the data floating around ? Lots of buffering. This issue suggests
to me that any use of VFS will eventually kill the Server. Even with smaller files it will
eventually use all available memory. I guess I did not understand the actual reason for this
issue from prior discussion.
>
> I will try your extra parameters today though.
>
> Thanks
> Kim
>
>
> -----Original Message-----
> From: Andreas Veithen [mailto:andreas.veithen@gmail.com]
> Sent: Thursday, 19 March 2009 5:48 PM
> To: dev@synapse.apache.org
> Subject: Re: VFS - Synapse Memory Leak
>
> Kim,
>
> Can you post your current synapse.xml as well as the stack trace you get now?
>
> Andreas
>
> On Thu, Mar 19, 2009 at 07:20, kimhorn <kim.horn@icsglobal.net> wrote:
>>
>> Using the last stable build from 15 March 2009 I still get exactly same
>> behaviour as originally
>> described with the above script. VFS still just dies. Would your fixes be in
>> this ?
>>
>> Using the last st
>>
>> Andreas Veithen-2 wrote:
>>>
>>> I committed the code and it will be available in the next WS-Commons
>>> transport build. The methods are located in
>>> org.apache.axis2.format.ElementHelper in the axis2-transport-base
>>> module.
>>>
>>> Andreas
>>>
>>> On Thu, Mar 12, 2009 at 00:06, Kim Horn <kim.horn@icsglobal.net> wrote:
>>>> Hello Andreas,
>>>> This is great and really helps, have not had time to try it out but will
>>>> soon.
>>>>
>>>> Contributing the java.io.Reader would be a great help but it will take me
>>>> a while to get up to speed to do the Synapse iterator.
>>>>
>>>> In the short term I am going to use a brute force approach that is now
>>>> feasible given the memory issue is resolved. Just thought of this one
>>>> today. Use VFS proxy to FTP file locally; so streaming helps here. A
>>>> POJOCommand on <out> to split file into another directory, stream in
and
>>>> out. Another independent VFS proxy watches that directory and submits
>>>> each file to Web service. Hopefully memory will be fine. Overloading the
>>>> destination may still be an issue ?
>>>>
>>>> Kim
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Andreas Veithen [mailto:andreas.veithen@gmail.com]
>>>> Sent: Monday, 9 March 2009 10:55 PM
>>>> To: dev@synapse.apache.org
>>>> Subject: Re: VFS - Synapse Memory Leak
>>>>
>>>> The changes I did in the VFS transport and the message builders for
>>>> text/plain and application/octet-stream certainly don't provide an
>>>> out-of-the-box solution for your use case, but they are the
>>>> prerequisite.
>>>>
>>>> Concerning your first proposed solution (let the VFS write the content
>>>> to a temporary file), I don't like this because it would create a
>>>> tight coupling between the VFS transport and the mediator. A design
>>>> goal should be that the solution will still work if the file comes
>>>> from another source, e.g. an attachment in an MTOM or SwA message.
>>>>
>>>> I thing that an all-Synapse solution (2 or 3) should be possible, but
>>>> this will require development of a custom mediator. This mediator
>>>> would read the content, split it up (and store the chunks in memory or
>>>> an disk) and executes a sub-sequence for each chunk. The execution of
>>>> the sub-sequence would happen synchronously to limit the memory/disk
>>>> space consumption (to the maximum chunk size) and to avoid flooding
>>>> the destination service.
>>>>
>>>> Note that it is probably not possible to implemented the mediator
>>>> using a script because of the problematic String handling. Also,
>>>> Spring, POJO and class mediators don't support sub-sequences (I
>>>> think). Therefore it should be implemented as a full-featured Java
>>>> mediator, probably taking the existing iterate mediator as a template.
>>>> I can contribute the required code to get the text content in the form
>>>> of a java.io.Reader.
>>>>
>>>> Regards,
>>>>
>>>> Andreas
>>>>
>>>> On Mon, Mar 9, 2009 at 03:05, kimhorn <kim.horn@icsglobal.net> wrote:
>>>>>
>>>>> Although this is a good feature it may not solve the actual problem ?
>>>>> The main first issue on my list was the memory leak.
>>>>> However, the real problem is once I get this massive files I  have to
>>>>> send
>>>>> it to a web Service that can only take it in small chunks (about 14MB)
.
>>>>> Streaming it straight out would just kill the destination Web service.
>>>>> It
>>>>> would get the memory error. The text document can be split apart easily,
>>>>> as
>>>>> it has independant records on each line seperated by <CR> <LF>.
>>>>>
>>>>> In an earlier post; that was not responded too, I mentioned:
>>>>>
>>>>> "Otherwise; for large EDI files a VFS iterator Mediator that streams
>>>>> through
>>>>> input file and outputs smaller
>>>>> chunks for processing, in Synapse, may be a solution ? "
>>>>>
>>>>> So I had mentioned a few solutions, in prior posts, solution now are:
>>>>>
>>>>> 1) VFS writes straight to temporary file, then a Java mediator can
>>>>> process
>>>>> the file by splitting it into many smaller files. These files then
>>>>> trigger
>>>>> another VFS proxy that submits these to the final web Service.
>>>>> The problem is is that is uses the file system (not so bad).
>>>>> 2) A Java Mediator takes the <text> package and splits it up by
wrapping
>>>>> into many XML <data> elements that can then be acted on by a Synapse
>>>>> Iterator. So replace the text message with many smaller XML elements.
>>>>> Problem is that this loads whole message into memory.
>>>>> 3) Create another Iterator in Synapse that works on Regular expression
>>>>> (to
>>>>> split the text data) or actually uses a for loop approach to chop the
>>>>> file
>>>>> into chunks based on the loop index value. E.g. Index = 23 means a 14K
>>>>> chunk
>>>>> 23 chunks into the data.
>>>>> 4) Using the approach proposed now - just submit the file straight
>>>>> (stream
>>>>> it) to another web service that chops it up. It may return an XML
>>>>> document
>>>>> with many sub elelements that allows the standard Iterator to work.
>>>>> Similar
>>>>> to (2) but using another service rather than Java to split document.
>>>>> 5) Using the approach proposed now - just submit the file straight
>>>>> (stream
>>>>> it) to another web service that chops it up but calls a Synapse proxy
>>>>> with
>>>>> each small packet of data that then forwards it to the final WEb
>>>>> Service. So
>>>>> the Web Service iterates across the data; and not Synapse.
>>>>>
>>>>> Then other solutions replace Synapse with a stand alone Java program
at
>>>>> the
>>>>> front end.
>>>>>
>>>>> Another issue here is throttling: Splitting the file is one issues but
>>>>> submitting 100's of calls in parralel to the destination service would
>>>>> result in time outs... So need to work in throttling.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Ruwan Linton wrote:
>>>>>>
>>>>>> I agree and can understand the time factor and also +1 for reusing
>>>>>> stuff
>>>>>> than trying to invent the wheel again :-)
>>>>>>
>>>>>> Thanks,
>>>>>> Ruwan
>>>>>>
>>>>>> On Sun, Mar 8, 2009 at 4:08 PM, Andreas Veithen
>>>>>> <andreas.veithen@gmail.com>wrote:
>>>>>>
>>>>>>> Ruwan,
>>>>>>>
>>>>>>> It's not a question of possibility, it is a question of available
time
>>>>>>> :-)
>>>>>>>
>>>>>>> Also note that some of the features that we might want to implement
>>>>>>> have some similarities with what is done for attachments in Axiom
>>>>>>> (except that an attachment is only available once, while a file
over
>>>>>>> VFS can be read several times). I think there is also some existing
>>>>>>> code in Axis2 that might be useful. We should not reimplement
these
>>>>>>> things but try to make the existing code reusable. This however
is
>>>>>>> only realistic for the next release after 1.3.
>>>>>>>
>>>>>>> Andreas
>>>>>>>
>>>>>>> On Sun, Mar 8, 2009 at 03:47, Ruwan Linton <ruwan.linton@gmail.com>
>>>>>>> wrote:
>>>>>>> > Andreas,
>>>>>>> >
>>>>>>> > Can we have the caching at the file system as a property
to support
>>>>>>> the
>>>>>>> > multiple layers touching the full message and is it possible
make it
>>>>>>> to
>>>>>>> > specify a threshold for streaming? For example if the message
is
>>>>>>> touched
>>>>>>> > several time we might still need streaming but not for the
100KB or
>>>>>>> lesser
>>>>>>> > files.
>>>>>>> >
>>>>>>> > Thanks,
>>>>>>> > Ruwan
>>>>>>> >
>>>>>>> > On Sun, Mar 8, 2009 at 1:12 AM, Andreas Veithen <
>>>>>>> andreas.veithen@gmail.com>
>>>>>>> > wrote:
>>>>>>> >>
>>>>>>> >> I've done an initial implementation of this feature.
It is
>>>>>>> available
>>>>>>> >> in trunk and should be included in the next nightly
build. In order
>>>>>>> to
>>>>>>> >> enable this in your configuration, you need to add the
following
>>>>>>> >> property to the proxy:
>>>>>>> >>
>>>>>>> >> <parameter name="transport.vfs.Streaming">true</parameter>
>>>>>>> >>
>>>>>>> >> You also need to add the following mediators just before
the <send>
>>>>>>> >> mediator:
>>>>>>> >>
>>>>>>> >> <property action="remove" name="transportNonBlocking"
>>>>>>> scope="axis2"/>
>>>>>>> >> <property action="set" name="OUT_ONLY" value="true"/>
>>>>>>> >>
>>>>>>> >> With this configuration Synapse will stream the data
directly from
>>>>>>> the
>>>>>>> >> incoming to the outgoing transport without storing it
in memory or
>>>>>>> in
>>>>>>> >> a temporary file. Note that this has two other side
effects:
>>>>>>> >> * The incoming file (or connection in case of a remote
file) will
>>>>>>> only
>>>>>>> >> be opened on demand. In this case this happens during
execution of
>>>>>>> the
>>>>>>> >> <send> mediator.
>>>>>>> >> * If during the mediation the content of the file is
needed several
>>>>>>> >> time (which is not the case in your example), it will
be read
>>>>>>> several
>>>>>>> >> times. The reason is of course that the content is not
cached.
>>>>>>> >>
>>>>>>> >> I tested the solution with a 2GB file and it worked
fine. The
>>>>>>> >> performance of the implementation is not yet optimal,
but at least
>>>>>>> the
>>>>>>> >> memory consumption is constant.
>>>>>>> >>
>>>>>>> >> Some additional comments:
>>>>>>> >> * The transport.vfs.Streaming property has no impact
on XML and
>>>>>>> SOAP
>>>>>>> >> processing: this type of content is processed exactly
as before.
>>>>>>> >> * With the changes described here, we have now two different
>>>>>>> policies
>>>>>>> >> for plain text and binary content processing: in-memory
caching +
>>>>>>> no
>>>>>>> >> streaming (transport.vfs.Streaming=false) and no caching
+ deferred
>>>>>>> >> connection + streaming (transport.vfs.Streaming=true).
Probably we
>>>>>>> >> should define a wider range of policies in the future,
including
>>>>>>> file
>>>>>>> >> system caching + streaming.
>>>>>>> >> * It is necessary to remove the transportNonBlocking
property
>>>>>>> >> (MessageContext.TRANSPORT_NON_BLOCKING) to prevent the
<send>
>>>>>>> mediator
>>>>>>> >> (more precisely the OperationClient) from executing
the outgoing
>>>>>>> >> transport in a separate thread. This property is set
by the
>>>>>>> incoming
>>>>>>> >> transport. I think this is a bug since I don't see any
valid reason
>>>>>>> >> why the transport that handles the incoming request
should
>>>>>>> determine
>>>>>>> >> the threading behavior of the transport that sends the
outgoing
>>>>>>> >> request to the target service. Maybe Asankha can comment
on this?
>>>>>>> >>
>>>>>>> >> Andreas
>>>>>>> >>
>>>>>>> >> On Thu, Mar 5, 2009 at 07:21, kimhorn <kim.horn@icsglobal.net>
>>>>>>> wrote:
>>>>>>> >> >
>>>>>>> >> > Thats good; as this stops us using Synapse.
>>>>>>> >> >
>>>>>>> >> >
>>>>>>> >> >
>>>>>>> >> > Asankha C. Perera wrote:
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> >> >>> Exception in thread "vfs-Worker-4" java.lang.OutOfMemoryError:
>>>>>>> Java
>>>>>>> >> >>> heap
>>>>>>> >> >>> space
>>>>>>> >> >>>         at
>>>>>>> >> >>>
>>>>>>> >> >>>
>>>>>>> java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:99)
>>>>>>> >> >>>         at
>>>>>>> >> >>>
>>>>>>> java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:518)
>>>>>>> >> >>>         at java.lang.StringBuffer.append(StringBuffer.java:307)
>>>>>>> >> >>>         at java.io.StringWriter.write(StringWriter.java:72)
>>>>>>> >> >>>         at
>>>>>>> org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1129)
>>>>>>> >> >>>         at
>>>>>>> org.apache.commons.io.IOUtils.copy(IOUtils.java:1104)
>>>>>>> >> >>>         at
>>>>>>> org.apache.commons.io.IOUtils.copy(IOUtils.java:1078)
>>>>>>> >> >>>         at
>>>>>>> org.apache.commons.io.IOUtils.toString(IOUtils.java:382)
>>>>>>> >> >>>         at
>>>>>>> >> >>>
>>>>>>> >> >>>
>>>>>>> org.apache.synapse.format.PlainTextBuilder.processDocument(PlainTextBuilder.java:68)
>>>>>>> >> >>>
>>>>>>> >> >> Since the content type is text, the plain text
formatter is
>>>>>>> trying
>>>>>>> to
>>>>>>> >> >> use a String to parse as I see.. which is a
problem for large
>>>>>>> content..
>>>>>>> >> >>
>>>>>>> >> >> A definite bug we need to fix ..
>>>>>>> >> >>
>>>>>>> >> >> cheers
>>>>>>> >> >> asankha
>>>>>>> >> >>
>>>>>>> >> >> --
>>>>>>> >> >> Asankha C. Perera
>>>>>>> >> >> AdroitLogic, http://adroitlogic.org
>>>>>>> >> >>
>>>>>>> >> >> http://esbmagic.blogspot.com
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> ---------------------------------------------------------------------
>>>>>>> >> >> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>>>>>> >> >> For additional commands, e-mail: dev-help@synapse.apache.org
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> >> >>
>>>>>>> >> >
>>>>>>> >> > --
>>>>>>> >> > View this message in context:
>>>>>>> >> >
>>>>>>> http://www.nabble.com/VFS---Synapse-Memory-Leak-tp22344176p22345904.html
>>>>>>> >> > Sent from the Synapse - Dev mailing list archive
at Nabble.com.
>>>>>>> >> >
>>>>>>> >> >
>>>>>>> >> >
>>>>>>> ---------------------------------------------------------------------
>>>>>>> >> > To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>>>>>> >> > For additional commands, e-mail: dev-help@synapse.apache.org
>>>>>>> >> >
>>>>>>> >> >
>>>>>>> >>
>>>>>>> >>
>>>>>>> ---------------------------------------------------------------------
>>>>>>> >> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>>>>>> >> For additional commands, e-mail: dev-help@synapse.apache.org
>>>>>>> >>
>>>>>>> >
>>>>>>> >
>>>>>>> >
>>>>>>> > --
>>>>>>> > Ruwan Linton
>>>>>>> > http://wso2.org - "Oxygenating the Web Services Platform"
>>>>>>> > http://ruwansblog.blogspot.com/
>>>>>>> >
>>>>>>>
>>>>>>> ---------------------------------------------------------------------
>>>>>>> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>>>>>> For additional commands, e-mail: dev-help@synapse.apache.org
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Ruwan Linton
>>>>>> http://wso2.org - "Oxygenating the Web Services Platform"
>>>>>> http://ruwansblog.blogspot.com/
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> View this message in context:
>>>>> http://www.nabble.com/VFS---Synapse-Memory-Leak-tp22344176p22405973.html
>>>>> Sent from the Synapse - Dev mailing list archive at Nabble.com.
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>>>> For additional commands, e-mail: dev-help@synapse.apache.org
>>>>>
>>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>>> For additional commands, e-mail: dev-help@synapse.apache.org
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>>> For additional commands, e-mail: dev-help@synapse.apache.org
>>>>
>>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>>> For additional commands, e-mail: dev-help@synapse.apache.org
>>>
>>>
>>>
>>
>> --
>> View this message in context: http://www.nabble.com/VFS---Synapse-Memory-Leak-tp22344176p22594321.html
>> Sent from the Synapse - Dev mailing list archive at Nabble.com.
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: dev-unsubscribe@synapse.apache.org
>> For additional commands, e-mail: dev-help@synapse.apache.org
>>
>>
>
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>
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