rsync - Jan 2017 - [Bug 12498] New: --fuzzy --fuzzy hugely impacts performance even if its' not needed

https://bugzilla.samba.org/show_bug.cgi?id=12498

            Bug ID: 12498
           Summary: --fuzzy --fuzzy hugely impacts performance even if
                    its' not needed
           Product: rsync
           Version: 3.1.2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P5
         Component: core
          Assignee: wayned at samba.org
          Reporter: ben.rubson at gmail.com
        QA Contact: rsync-qa at samba.org

Hello,

I make backups to a Rsync daemon.
Each backup is made to an empty directory, using 20 --link-dest parameters, so
that already uploaded files are hard-linked.
Perfect.

I made some tests adding --fuzzy --fuzzy so that non-existing files can use a
base-file, when possible.

It works perfectly, really good thing to find a base-file within link-dest
directories.

However, it really slows down the backup process, even when it's not needed.
For example, it terribly impacts performance even for a backup with no new
files at all, for which all files will be hard-linked.

Here are some backup durations for a backup with no new files :
- without -yy                 :  9 seconds
- with -y                     :  9 seconds
- with --y and  1 --link-dest : 11 seconds
- with --y and  8 --link-dest : 22 seconds
- with --y and 20 --link-dest : 37 seconds

My question is then, could it be possible for --fuzzy --fuzzy (-yy) to only
work for files which really need to be uploaded ?
So to avoid working for files which will simply be hard-linked.

Would such a modification only impact daemon side ? (would be great)

Thank you very much !

Best regards,

Ben

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https://bugzilla.samba.org/show_bug.cgi?id=12498

--- Comment #1 from Ben RUBSON <ben.rubson at gmail.com> ---
Created attachment 13748
  --> https://bugzilla.samba.org/attachment.cgi?id=13748&action=edit
Do fuzzy only when needed

Here's a patch for this issue. Thx !

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https://bugzilla.samba.org/show_bug.cgi?id=12498

Ben RUBSON <ben.rubson at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|3.1.2                       |3.1.3

--- Comment #2 from Ben RUBSON <ben.rubson at gmail.com> ---
This patch still works as expected with rsync 3.1.3.
Thx !

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Ben RUBSON <ben.rubson at gmx.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |MOVED
             Status|NEW                         |RESOLVED

--- Comment #3 from Ben RUBSON <ben.rubson at gmx.com> ---
Patch moved : https://github.com/WayneD/rsync/pull/1

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