Delta compression

Legacy Execution
1

Hi,
I would like to know how delta compression works in Octopus. In my project, though the delta compression is applied, the package size is same as the previous package. What exactly does applying delta means?
Also, I would like to know if it is possible that the package will have only the file which is modified.
So that, if I turn off “Purge” option, and i have modified only once single JS file, the package will contain only that file and nothing else?

Thanks

3

Hi,

Thanks for getting in touch! We have a great in-depth documentation page on our Delta Compression feature.

As for the Purge option, this is related to using a Custom Installation Directory (CID). If this option is enabled, the CID you are deploying to will be purged before the entire package is extracted and copied over from the temp directory to the CID.

If you have any further questions here or are running into any issues, please let me know. :slight_smile:

Best regards,
Daniel

4

Thanks very much for the response, Daniel.
What exactly the delta package include? It is of the same size as of the actual package. We couldn’t understand the exact behavior from the documentation. Could you please explain that?

5

Hi,

Thanks for getting back! We have a more in-depth description of exactly what is going on with our delta compression over on our Octodiff GitHub page.

Essentially the delta file includes:

* Metadata about the signature file and algorithms used

* Hash of the file that the original signature was created from (basis file hash)

* A series of instructions to re-create the new-file which reference the basis file.

The delta file will always be smaller than the package. If over 80% of the package is changed, we will upload the entire package without any delta compression.

This feature is designed to make transferring files quicker when the target already has a mostly similar version of the file. Essentially by only copying what has changed and some extra data required to rebuild the package on the other end, then rebuilding the entire package at the target using the changes in the delta package.

I hope that helps clear things up a bit. Let me know if you have any further questions here. :slight_smile:

Best regards,
Daniel

6

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.