Merge pull request #4544 from ThomasWaldmann/improve-compact

small borg compact improvements, fixes #4522

docs/usage/compact.rst

@@ -7,9 +7,7 @@ Examples
     # compact segments and free repo disk space
     $ borg compact /path/to/repo
 
-    # same as above plus clean up 17byte commit-only segments,
-    # use this one time after upgrading borg (server) to 1.2+
-    # to clean up the tiny segments files created by borg 1.1:
+    # same as above plus clean up 17byte commit-only segments
     $ borg compact --cleanup-commits /path/to/repo
 
 

src/borg/archiver.py

@@ -2777,12 +2777,20 @@ class Archiver:
         This command frees repository space by compacting segments.
 
         Use this regularly to avoid running out of space - you do not need to use this
-        after each borg command though.
+        after each borg command though. It is especially useful after deleting archives,
+        because only compaction will really free repository space.
 
         borg compact does not need a key, so it is possible to invoke it from the
         client or also from the server.
 
-        Depending on the amount of segments that need compaction, it may take a while.
+        Depending on the amount of segments that need compaction, it may take a while,
+        so consider using the ``--progress`` option.
+
+        When using ``--verbose``, borg will output an estimate of the freed space.
+
+        After upgrading borg (server) to 1.2+, you can use ``borg compact --cleanup-commits``
+        to clean up the numerous 17byte commit-only segments that borg 1.1 did not clean up
+        due to a bug. It is enough to do that once per repository.
 
         See :ref:`separate_compaction` in Additional Notes for more details.
         """)

src/borg/repository.py

@@ -695,6 +695,7 @@ class Repository:
         if not self.compact:
             logger.debug('nothing to do: compact empty')
             return
+        freed_space = 0
         index_transaction_id = self.get_index_transaction_id()
         segments = self.segments
         unused = []  # list of segments, that are not used anymore
@@ -734,6 +735,7 @@ class Repository:
                              segment, freeable_ratio * 100.0, freeable_space)
                 pi.show()
                 continue
+            freed_space += freeable_space  # this is what we THINK we can free
             segments.setdefault(segment, 0)
             logger.debug('compacting segment %d with usage count %d (freeable: %2.2f%% [%d bytes])',
                          segment, segments[segment], freeable_ratio * 100.0, freeable_space)
@@ -814,6 +816,7 @@ class Repository:
             pi.show()
         pi.finish()
         complete_xfer(intermediate=False)
+        logger.info('compaction freed about %s repository space.', format_file_size(freed_space))
         logger.debug('compaction completed.')
 
     def replay_segments(self, index_transaction_id, segments_transaction_id):