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From: Andreas Veithen <andreas.veithen@gmail.com>
Date: Sat, 15 Sep 2012 08:18:25 +0200
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 <CADx4_uXrs=rwd61a7GofTGHn88pJ7AZxycVbVy5x6uUwq-en3Q@mail.gmail.com>
Subject: Re: Improving Synapse CBR performance.
To: dev@synapse.apache.org
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On Wed, Sep 12, 2012 at 10:36 PM, Hiranya Jayathilaka
<hiranya911@gmail.com> wrote:
> Hi Amila,
>
> AFAIU this improvement gets rid of the SOAP serialization overhead (at the
> cost of more memory). This is certainly an interesting idea but goes against
> the philosophy that we have been following up to now - we don't buffer any
> message content in-memory. This philosophy helps us to keep the memory usage
> at a reasonably constant level even under largest volumes of traffic. In
> general we can say the memory usage will not be highly affected by a burst
> of very large (say > 10M) messages. But the moment we start buffering
> message content in memory we loose that.

That argument is not entirely correct. What Amila proposes is to keep
in memory the part of the message that has already been read (plus of
course a few KB read in advance). That would only add to the memory
already consumed by the Axiom object model constructed for that part
of the message. There would thus be an increase in memory usage, but
it the increase would be roughly proportional.

> I think the proper way to improve current performance level in Synapse is to
> get Synapse to use the pass through transport by default. We already
> discussed this on the list [2] a few months back and the idea was to use the
> pass through transport by default and fix the transport so that it can also
> handle non-pass through scenarios (CBR, transform, security etc). I've
> actually done a POC for this and got pretty much all the Synapse samples to
> work except for RM scenarios. I'm currently doing some tweaks to this
> implementation and when completed I'll commit the code in.
>
> I agree with your idea about making mediators say whether they want to
> access the message content or not. Basically I had to implement this as a
> part of the above mentioned POC. However I did it by adding a new method to
> the Mediator interface (isContentAware). Each mediator returns true/false
> depending on what they do and how they are configured. For an example <log/>
> will return false where as <log level="full"/> will return true. <xslt/>
> will always return true. <filter/> will return true/false depending on the
> type of XPath expression used. This way we tackle the problem in a more
> elegant and flexible manner without involving the user. I think using
> properties for this purpose is a hack and will be a hassle to the users.
>
> With the above implementation applied to your proxy configuration, message
> will be built by the SOAPBuilder when it hits the filter mediator (due to
> the XPath). On the out sequence, neither the builder nor the formatter will
> get engaged, and the message will be simply passed through Synapse at the
> transport level.
>
> I also like your idea about implementing a more efficient XPath engine that
> only builds a part of the message. That's something we have lacked for a
> while
>
> Thanks,
> Hiranya
>
> [2] -
> http://old.nabble.com/Message-Relay-Support-for-Synapse-to33693068.html
>
>
> On Wed, Sep 12, 2012 at 9:01 AM, Amila Suriarachchi
> <amilasuriarachchi@gmail.com> wrote:
>>
>> hi all,
>>
>> For SOAP message based content based routing, currently we use SOAPBuilder
>> and SOAPMessageFormater to build the soap envelop and serialize it. But
>> however in the content based routing the only message part required to read
>> is the parts that has the content need for routing. On the other hand there
>> is no need to build the response xml message if no mediation required for
>> response.
>>
>> Therefore we can make this perform better with the following steps. First
>> at the message builder level we create a buffered input stream to buffer the
>> read message and set this as a message context property. Then at the synapse
>> engine level we can copy this bufferedInput stream to out message context.
>> Now at the out message context we can access the buffered input stream and
>> use that to directly serialize the message from the input stream after
>> resetting the input stream.
>>
>> I have created the related patch here[1]. With this patch I could improve
>> the TPS for the following proxy services with 10k message from 1,700.7 to
>> 12,135.48 (25% gain).
>>
>>
>> <proxy name="CBRProxy" transports="https http" startOnLoad="true">
>>
>> <target>
>>
>> <inSequence>
>>
>> <property name="passThroughProxy" value="true" scope="default"
>> type="STRING"/>
>>
>> <filter xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
>> source="//order[1]/symbol" regex="IBM">
>>
>> <then>
>>
>> <send>
>>
>> <endpoint key="RealService"/>
>>
>> </send>
>>
>> </then>
>>
>> <else>
>>
>> <makefault version="soap11">
>>
>> <code xmlns:sf11="http://schemas.xmlsoap.org/soap/envelope/"
>> value="sf11:Server"/>
>>
>> <reason value="First order must be for the symbol IBM"/>
>>
>> </makefault>
>>
>> <header name="To" action="remove"/>
>>
>> <property name="RESPONSE" value="true"/>
>>
>> <send/>
>>
>> </else>
>>
>> </filter>
>>
>> </inSequence>
>>
>> </target>
>>
>> <publishWSDL key="ProxyWSDL-embedded.wsdl"/>
>>
>> </proxy>
>>
>>
>> Here are the other improvements can be done for this method.
>>
>> Here user have to set whether it is a pass through proxy or not using a
>> property mediator. However we can use some mechanism where each synapse
>> mediator set a property if that change the incoming message. If the message
>> has not been changed that can be pass through like this.
>>
>> I have used buffered Input stream here. We may write a custom Input stream
>> reader to perform this job better.
>>
>> Currently Axiom xpath build the whole soap envelope. Therefore if we can
>> write an axiom xpath engine which only builds the required parts performance
>> can be further improved.
>>
>> I have created the patch basically demonstrate the concept. There can be
>> more efficient way of implementing as well.
>>
>> WDTY?
>>
>> Thanks,
>>
>> Amila.
>>
>> [1] https://issues.apache.org/jira/browse/SYNAPSE-909
>>
>>
>>
>> --
>> Amila Suriarachchi
>> WSO2 Inc.
>> blog: http://amilachinthaka.blogspot.com/
>
>
>
>
> --
> Hiranya Jayathilaka
> Mayhem Lab/RACE Lab;
> Dept. of Computer Science, UCSB;  http://cs.ucsb.edu
> E-mail: hiranya@cs.ucsb.edu;  Mobile: +1 (805) 895-7443
> Blog: http://techfeast-hiranya.blogspot.com

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