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This blog is the extension of following blogs.

Background

Whenever large (binary) file needs to be transferred by using PI, there might be a chance for Out of Memory error which might results in server restart.  Technically, it often fails in the sender adapter.

/wp-content/uploads/2011/12/senderfailure_122168.png

The most popular work around is to split the file in to multiple parts in Sender Adapter and Combining them in Receiver Adapter (via OS Scripts)

From PI 7.30 onwards File/FTP adapter natively supports transferring large size files by splitting them in to smaller chunks based on the configured size. Each chunk will be processed as an individual XI Message in sender adapter and all the chunks are combined based on the sequence in receiver adapter. Since all the chunks have to be combined in the actual order, QoS EOIO has to be used to enable this feature.

LFTOverview.png

Configuration Options

Select ‘EOIO’ as a QoS under Processing tab.

/wp-content/uploads/2011/12/qosconfig_122170.png

After that select ‘Advanced Mode‘ under ‘Advanced’ Tab

Option 1

You can choose the required chunk size option from the given list of 1, 2, 5, 10, 20 and 50 MB.

/wp-content/uploads/2011/12/basicmode_122174.png

Option 2

Custom values which are not possible in default options can also be configured in additional parameters.

Parameter Name

Possible Values

chunkMode  

Non emptry string  will be considered as true

chunkSizeKB

Positive Numeric  Value

/wp-content/uploads/2011/12/advancedmode_122175.png

Processing in Sender Adapter

  • Basic Mode will be enabled only if QoS is EOIO
  • Chunk Mode related Advanced Mode parameters will be ignored if QoS  not EOIO
  • If chunkSizeKB is not defined /incorrect value, default is 10KB
  • If both are configured, Basic mode will have higher precedence

Sender Adapter will create XI message with additional dynamic headers for each chunk and forwarded to Messaging System for IRD processing.

Example

For this example, chunk size is configured as 2 MB and the below input file (~4.5 MB) is used.

/wp-content/uploads/2011/12/inputfile_122176.png

For demo purpose and to identify/analyze how the actual split happens, the input file is created with the data like below ( 1 to 600000)

inputfilecontent.PNG

As per the configuration, three chunks should be created with the size of 2 MB, 2MB and ~500 KB.

/wp-content/uploads/2011/12/mdt_122178.png

Chunk 1 (2 MB)

Transferring first 2 MB

/wp-content/uploads/2011/12/chunk1_122179.png

Chunk 2 (2 MB)

Transferring next 2 MB (Total 4 MB)

/wp-content/uploads/2011/12/chunk2_122180.png

Chunk 3 (~500 KB)

Transferring the remaining ~500 KB (Total ~4.5 MB)

/wp-content/uploads/2011/12/chunk3_122181.png

Dynamic Headers

The entire chunk mode related dynamic headers will be set under the namespace http://sap.com/xi/XI/System/Generic

Header Value
ChunkStart Start of the Chunk (Position of bytes)
ChunkMode Active/End
ChunkKey Unique Key (Same for all the chunks for a particular file)

The corresponding screenshots for all 3 chunks are given below.

First Chunk

/wp-content/uploads/2011/12/dc1_122182.png

Next Chunk

/wp-content/uploads/2011/12/dc2_122183.png

Last Chunk

/wp-content/uploads/2011/12/dc3_122184.png

If multiple files sent from different file sender channels, receiver adapter uses the chunk key to identify the proper output file(for combining). During the creation(and append) of output file, it uses the chunk key like below.

http://wiki.sdn.sap.com/wiki/download/attachments/286097433/chunkkey.png

In Temp mode, the temp files won’t be deleted till the last chunk is received.

Overall Control Flow

control.PNG

Recovery Mode

If the input file is very large, it would normally take more time to be transferred completely.  If there is any server failure in the middle, the transfer can resumed from the chunk it stopped (Not from the beginning)

Individual Payloads after Split

Though this feature operates only on binary mode, text file is used to analyze how the split happens during chunk creation.

Payload of Chunk 1

payload1.PNG

Payload of Chunk 2

http://wiki.sdn.sap.com/wiki/download/attachments/286097433/payload2.PNG

Payload of Chunk 3

http://wiki.sdn.sap.com/wiki/download/attachments/286097433/payload3.PNG

As per the above screenshots, the split never cosiders the payload. It’s just a binary split. So the following limitations would apply

  • Only for File Sender to File Receiver
  • No Mapping
  • No Content Based Routing
  • No Content Conversion
  • No Custom Modules

Technically, other type of receiver adapters can be used. But it won’t have the option to combine the chunks.

Does any special configuration required in File Receiver?

No. File receiver will automatically identify & combine the chunks using dynamic headers.

How to choose the chunk size? Smaller chunk size ensures more reliability?

Yes.  But significantly affects the performance. Smaller chunk size creates more chunks (more XI messages)

Troubleshooting

If chunks are stuck in the EOIO queue, it can be monitored with

http://host:port/MessagingSystem/monitor/sequenceMonitor.jsp

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20 Comments

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  1. Bhavesh Kantilal
    Hello, The blog links in your blog point to the same blog. Is this feature available on 7.1? I was under the impression that this is a feature available only from 7.31

    A very helpful feature! Great blog with good explanation!

    (0) 
  2. Bhavesh Kantilal
    Hello
    Does this feature continue to support ASMA – FileName? Can I use it to transfer files from source to target with same original filename?

    I see no reason it shouldn’t but would be good if this can be confirmed.

    Regards
    Bhavesh

    (0) 
  3. Martin Babayan

    Hi,

    Have you ever been able to do the same within ICO?

    I configured a classical scenario in Pi 7.40 and it worked fine. Then I decided to migrate it ICO (just for test) and now it’s failing with error in sender CC “Unable to parse XML message payload”. But why it is trying to parse the file?

    Will appreciate your input.

    (0) 
  4. Venu Gopal D

    Hi Siva,

    Chunk mode will be only useful for file to file scenarios? not useful for File to Proxy interfaces? Please let me know

    Thanks,

    Venu

    (0) 
  5. G SHIVA

    Hi Siva ,

    Can we append two files at receiver side, when we are using QOS : EOIO for sender communication channel with advanced selection for source option (when are try to pick multiple files from multiple directories??)

    Thanks,
    Shiva
     

    (0) 
  6. Carlo Zabala

    I’ve tried using this temp mode together with chunk mode and it is working on File to File Scenario but not on File to SFTP scenario.

    on SFTP it always overwrites the file.  Is there a way to use this function in SFTP Receiver?

    (0) 

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