Provide a less expensive version of git annex copy --to, enabled via --fast. This assumes that location tracking information is correct, rather than contacting the remote for every file.

Command/Move.hs

@@ -84,8 +84,14 @@ toStart dest move file = isAnnexed file $ \(key, _) -> do
 			return $ Just $ toPerform dest move key
 toPerform :: Remote.Remote Annex -> Bool -> Key -> CommandPerform
 toPerform dest move key = do
-	-- checking the remote is expensive, so not done in the start step
-	isthere <- Remote.hasKey dest key
+	-- Checking the remote is expensive, so not done in the start step.
+	-- In fast mode, location tracking is assumed to be correct,
+	-- and an explicit check is not done, when copying. When moving,
+	-- it has to be done, to avoid inaverdent data loss.
+	fast <- Annex.getState Annex.fast
+	isthere <- if fast && not move
+		then return $ Right True
+		else Remote.hasKey dest key
 	case isthere of
 		Left err -> do
 			showNote $ show err

debian/changelog

@@ -3,6 +3,9 @@ git-annex (0.20110326) UNRELEASED; urgency=low
   * annex.diskreserve can be given in arbitrary units (ie "0.5 gigabytes")
   * Generalized remotes handling, laying groundwork for remotes that are
     not regular git remotes.
+  * Provide a less expensive version of `git annex copy --to`, enabled
+    via --fast. This assumes that location tracking information is correct,
+    rather than contacting the remote for every file.
 
  -- Joey Hess <joeyh@debian.org>  Sat, 26 Mar 2011 14:36:16 -0400
 

doc/forum/batch_check_on_remote_when_using_copy.mdwn

@@ -6,3 +6,22 @@ Once all checks are done, one single transfer session should be started. Creatin
 
 
 -- RichiH
+
+> (Use of SHA is irrelevant here, copy does not checksum anything.)
+> 
+> I think what you're seeing is
+> that `git annex copy --to remote` is slow, going to the remote repository
+> every time to see if it has the file, while `git annex copy --from remote`
+> is fast, since it looks at what files are locally present.
+> 
+> That is something I mean to improve. At least `git annex copy --fast --to remote`
+> could easily do a fast copy of all files that are known to be missing from
+> the remote repository. When local and remote git repos are not 100% in sync,
+> relying on that data could miss some files that the remote doesn't have anymore,
+> but local doesn't know it dropped. That's why it's a candidate for `--fast`.
+> 
+> I've just implemented that.
+> 
+> While I do hope to improve ssh usage so that it sshs once, and feeds
+> `git-annex-shell` a series of commands to run, that is a much longer-term
+> thing. --[[Joey]]

doc/git-annex.mdwn

@@ -85,19 +85,21 @@ Many git-annex commands will stage changes for later `git commit` by you.
 
 * move [path ...]
   
-  When used with the --to option, moves the content of annexed files from
-  the current repository to the specified one.
-
   When used with the --from option, moves the content of annexed files
   from the specified repository to the current one.
 
+  When used with the --to option, moves the content of annexed files from
+  the current repository to the specified one.
+
 * copy [path ...]
 
+  When used with the --from option, copies the content of annexed files
+  from the specified repository to the current one.
+
   When used with the --to option, copies the content of annexed files from
   the current repository to the specified one.
 
-  When used with the --from option, copies the content of annexed files
-  from the specified repository to the current one.
+  To avoid contacting the remote to check if it has every file, specify --fast
 
 * unlock [path ...]
 
@@ -137,11 +139,15 @@ Many git-annex commands will stage changes for later `git commit` by you.
 
   With parameters, only the specified files are checked.
 
+  To avoid expensive checksum calculations, specify --fast
+
 * unused
 
   Checks the annex for data that is not used by any files currently
   in the annex, and prints a numbered list of the data.
 
+  To only show unused temp files, specify --fast
+
 * dropunused [number ...]
 
   Drops the data corresponding to the numbers, as listed by the last
@@ -286,8 +292,7 @@ Many git-annex commands will stage changes for later `git commit` by you.
 * --fast
 
   Enables less expensive, but also less thorough versions of some commands.
-  What is avoided depends on the command. A fast fsck avoids calculating
-  checksums; a fast unused only shows temp files and not other unused files.
+  What is avoided depends on the command.
 
 * --quiet