Changeset c837493 in trunk

Timestamp:

2019-03-14T17:11:47Z (6 years ago)

Author:

Jean-Paul Calderone <exarkun@…>

Branches:

master

Children:

dd7cb99

Parents:

05eab3ce

git-author:

Jean-Paul Calderone <exarkun@…> (2019-03-11 16:26:53)

git-committer:

Jean-Paul Calderone <exarkun@…> (2019-03-14 17:11:47)

Message:

Avoid some function dispatch overhead

Also, we might avoid some dict lookup overhead by being optimistic about
finding the entry. At worst, we do two lookups - which is just what we did
before.

File:

• src/allmydata/frontends/magic_folder.py (modified) (1 diff)

src/allmydata/frontends/magic_folder.py ¶

@@ -1870 +1870 @@
                     (local_dbentry.version == remote_version and local_dbentry.last_downloaded_uri != remote_uri)):
                     ADD_TO_DOWNLOAD_QUEUE.log(relpath=relpath_u)
-                    if scan_batch.has_key(relpath_u):
+
+                    # The scan_batch is shared across the scan of multiple
+                    # DMDs.  It is expected the DMDs will most often be mostly
+                    # synchronized with each other.  The common case, then, is
+                    # that there is already an entry for relpath_u.  So try to
+                    # make that the fast path: assume there is a value already
+                    # and extend it.  If there's not, we'll do an extra lookup
+                    # to initialize it.
+                    try:
                         scan_batch[relpath_u] += [(file_node, metadata)]
-                    else:
+                    except KeyError:
                         scan_batch[relpath_u] = [(file_node, metadata)]
             self._status_reporter(