Rev 3823: Bring in the caching-basis logic for generic fetch. in http://bzr.arbash-meinel.com/branches/bzr/brisbane/generic_fetch_ordering

John Arbash Meinel john at arbash-meinel.com
Wed Feb 18 17:13:56 GMT 2009


At http://bzr.arbash-meinel.com/branches/bzr/brisbane/generic_fetch_ordering

------------------------------------------------------------
revno: 3823
revision-id: john at arbash-meinel.com-20090218171343-4l9rgozo4hbj3l2h
parent: john at arbash-meinel.com-20090218163618-isb3yg01ygdx3m2n
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: generic_fetch_ordering
timestamp: Wed 2009-02-18 11:13:43 -0600
message:
  Bring in the caching-basis logic for generic fetch.
-------------- next part --------------
=== modified file 'bzrlib/repository.py'
--- a/bzrlib/repository.py	2009-02-18 14:57:11 +0000
+++ b/bzrlib/repository.py	2009-02-18 17:13:43 +0000
@@ -3278,15 +3278,43 @@
             return False
         return True
 
-    def _fetch_batch(self, revision_ids, basis_id, basis_tree):
+    def _get_delta_for_revision(self, basis_id, basis_tree, last_batch,
+                                new_batch, tree, parent_ids):
+        """Get the best delta and base for this revision.
+
+        :return: (basis_id, basis_tree, delta)
+        """
+        possible_trees = []
+        for parent_id in parent_ids:
+            if parent_id == basis_id:
+                possible_trees.append((basis_id, basis_tree))
+            elif parent_id in new_batch:
+                possible_trees.append((parent_id, new_batch[parent_id]))
+            elif parent_id in last_batch:
+                possible_trees.append((parent_id, last_batch[parent_id]))
+        if len(possible_trees) == 0:
+            # There either aren't any parents, or the parents aren't in the
+            # caches, so just use the last converted tree
+            possible_trees.append((basis_id, basis_tree))
+        deltas = []
+        for basis_id, basis_tree in possible_trees:
+            delta = tree.inventory._make_delta(basis_tree.inventory)
+            deltas.append((len(delta), basis_id, basis_tree, delta))
+        deltas.sort()
+        return deltas[0][1:]
+
+    def _fetch_batch(self, revision_ids, basis_id, basis_tree, last_batch):
         """Fetch across a few revisions.
 
         :param revision_ids: The revisions to copy
         :param basis_id: The revision_id of basis_tree
         :param basis_tree: A tree that is not in revision_ids which should
             already exist in the target.
-        :return: (basis_id, basis_tree) A new basis to use now that these trees
-            have been copied.
+        :param last_batch: A dict of {revid: rev_tree}. Used as potential basis
+            trees for computing a new delta.
+        :return: (basis_id, basis_tree, new_batch) A new basis to use now that
+            these trees have been copied, new_batch is a dict that can be
+            passed back in via last_batch
         """
         # Walk though all revisions; get inventory deltas, copy referenced
         # texts that delta references, insert the delta, revision and
@@ -3294,15 +3322,20 @@
         text_keys = set()
         pending_deltas = []
         pending_revisions = []
+        new_batch = {}
+        parent_map = self.source.get_parent_map(revision_ids)
         for tree in self.source.revision_trees(revision_ids):
             current_revision_id = tree.get_revision_id()
-            delta = tree.inventory._make_delta(basis_tree.inventory)
+            new_batch[current_revision_id] = tree
+            parent_ids = parent_map.get(current_revision_id, ())
+            basis_id, basis_tree, delta = self._get_delta_for_revision(
+                basis_id, basis_tree, last_batch, new_batch, tree, parent_ids)
+            # Find text entries that need to be copied
             for old_path, new_path, file_id, entry in delta:
                 if new_path is not None:
                     if not (new_path or self.target.supports_rich_root()):
-                        # We leave the inventory delta in, because that
-                        # will have the deserialised inventory root
-                        # pointer.
+                        # We don't copy the text for the root node unless the
+                        # target supports_rich_root.
                         continue
                     # TODO: Do we need:
                     #       "if entry.revision == current_revision_id" ?
@@ -3333,7 +3366,7 @@
             except errors.NoSuchRevision:
                 pass
             self.target.add_revision(revision.revision_id, revision)
-        return basis_id, basis_tree
+        return basis_id, basis_tree, new_batch
 
     def _fetch_all_revisions(self, revision_ids, pb):
         """Fetch everything for the list of revisions.
@@ -3345,14 +3378,15 @@
         """
         basis_id, basis_tree = self._get_basis(revision_ids[0])
         batch_size = 100
+        last_batch = {}
         for offset in range(0, len(revision_ids), batch_size):
             self.target.start_write_group()
             try:
                 pb.update('Transferring revisions', offset,
                           len(revision_ids))
                 batch = revision_ids[offset:offset+batch_size]
-                basis_id, basis_tree = self._fetch_batch(batch,
-                    basis_id, basis_tree)
+                basis_id, basis_tree, last_batch = self._fetch_batch(batch,
+                    basis_id, basis_tree, last_batch)
             except:
                 self.target.abort_write_group()
                 raise



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