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[closed] How can SCM data transfer between client and server be improved even more?


Arne Bister (2.6k12732) | asked Feb 10 '13, 12:12 p.m.
JAZZ DEVELOPER
closed Aug 17 '13, 10:45 a.m.
Since SCM data is compressed at the server, there is a concern that the following scenario is not yet optimized for performance:
- 10 MByte of XML File are loaded to a remote location
- one line of code is changed at client
- upon checkin 10 MByte of XML are transferred back, then compressed at server
This would mean 20 MByte of data transfer for a change of a few bytes.

Apparently Enhancement 34511 is asking for a similar improvement in Jazz Foundation.

In the meantime, what measures can be taken to prevent performance impact due to above scenario?

- Arne

Comments
Martin Wassermann commented Apr 08 '13, 9:17 a.m.

I’m very interested in this topic too. Did the RTC only transfer the delta of the changes or the complete file? And is the compression only on the jazz server or is the file transferred compressed and the client decompresses the file?

Is there an article that describe the transfer of the files from the server to the clients?


sam detweiler commented Apr 08 '13, 10:11 a.m.

SCM content sent to the client is compressed depending on the settings in the CCM server advanced properties (default = true)
the files are complete, not deltas.. the current state resolution is done at the server.

com.ibm.team.scm.service.internal.content.VersionedContentService
com.ibm.team.scm.service.internal.replication.ScmImportContentService

content INTO the server from the client is NOT compressed, and the entire file is sent, not a delta.

the files are stored and sent using the UUID name, not the filename. the UUID is unique for every change. The composition of the 'file' might be the entire changeset, not just one file.  (when using the caching proxy for builds, I see one file sent, but multiple files show up in the build workspace).


sam detweiler commented Apr 08 '13, 10:18 a.m.

that Enhancement appears targeted at reducing CPU load, not bytes sent from the server.

The question has been closed for the following reason: "The question is answered, right answer was accepted" by abister Aug 17 '13, 10:45 a.m.

Accepted answer


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sam detweiler (12.5k6189201) | answered Feb 10 '13, 4:49 p.m.
well, its not 10MB on the way out, cause the content is GZIP compressed.. the client end decompresses.

on our intranet, we have router implemented WAN acceleration which reduces the source content to ~5% of original data size to reduce waste WAN capacity. (the server and client both think they sent 10MB, but only 500k actual crosses the wan).  We are deploying caching proxy servers in our remote offices too, to eliminate even more need to transmit outbound..

but upload is so small compared to download for us.. 94-5% of all traffic (according to Jazzmon) is outbound.
Arne Bister selected this answer as the correct answer