[MERGE] Accelerate merge by skipping file existence check when merging execute bit

[Aaron Bentley]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi all,

This patch speeds up merge by avoiding unnecessary file-existence tests.

During merge, we may wish to set or unset the execute bit, but if the
file does not exist, we must not.  Currently, we check whether the file
exists whether or not we will set it.  This can happen for many files in
the tree.  This patch avoids unnecessary existence checks.

This accelerates execute bit merging, and also accelerates conflict
resolution.  Conflict resolution scales with the number of files that
have been referenced.  The fewer the number of referenced files, the
faster the resolution.  The existence check was causing files to be
referenced that otherwise would not have been, so skipping it speeds up
conflict resolution as well.

Aaron
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFH4W3/0F+nu1YWqI0RAj1lAJ4qgQDYRqa4CvUB25D1PS361jO2iACdFV71
xg7LMtOvg+N1TXlUYGo/1wU=
=pjxR
-----END PGP SIGNATURE-----
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Aaron's mergeable stuff-1921.patch
Type: text/x-diff
Size: 5357 bytes
Desc: not available
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20080319/28b79fff/attachment.bin