openstack/swift
Code Issues Proposed changes

Avoid premature shrinking in sharder probe test

Browse Source 
Previously test_misplaced_object_movement() deleted objects from both
shards and then relied on override-partitions option to selectively
run the sharder on root or shard containers and thereby control when
each shard range was identified for shrinking. This approach is flawed
when the second shard container lands in the same partition as the
root: running the sharder on the empty second shard's partition would
also cause the sharder to process the root and identify the second
shard for shrinking, resulting in premature shrinking of the second
shard.

Now, objects are only deleted from each shard range as that shard is
wanted to shrink.

Change-Id: I9f51621e8414e446e4d3f3b5027f6c40e01192c3
Drive-by: use the run_sharders() helper more often.
This commit is contained in:
Alistair Coles 2018-05-22 13:27:13 +01:00
parent 201223f7ff
commit 37ee89e47a
1 changed files with 29 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
test/probe/test_sharder.py
View File

@ -1778,54 +1778,60 @@ class TestContainerSharding(BaseTestContainerSharding):
self.assert_container_post_ok('sharded')
self.assert_container_listing(all_obj_names)
# delete all objects - updates redirected to shards
self.delete_objects(all_obj_names)
self.assert_container_listing([])
self.assert_container_post_ok('has objects')
# run sharder on shard containers to update root stats
# delete all objects in first shard range - updates redirected to shard
shard_ranges = self.get_container_shard_ranges()
self.assertLengthEqual(shard_ranges, 2)
self.run_sharders(shard_ranges)
self.assert_container_object_count(0)
shard_0_objects = [name for name in all_obj_names
if name in shard_ranges[0]]
shard_1_objects = [name for name in all_obj_names
if name in shard_ranges[1]]
self.delete_objects(shard_0_objects)
self.assert_container_listing(shard_1_objects)
self.assert_container_post_ok('has objects')
# run sharder on first shard container to update root stats
self.run_sharders(shard_ranges[0])
self.assert_container_object_count(len(shard_1_objects))
# First, test a misplaced object moving from one shard to another.
# run sharder on root to discover first shrink candidate
self.sharders.once(additional_args='--partitions=%s' % self.brain.part)
# then run sharder on first shard range to shrink it
shard_part, shard_nodes_numbers = self.get_part_and_node_numbers(
shard_ranges[0])
self.sharders.once(additional_args='--partitions=%s' % shard_part)
self.run_sharders(shard_ranges[0])
# force a misplaced object into the shrunken shard range to simulate
# a client put that was in flight when it started to shrink
misplaced_node = merge_object(shard_ranges[0], 'alpha', deleted=0)
# root sees first shard has shrunk, only second shard range used for
# listing so alpha object not in listing
self.assertLengthEqual(self.get_container_shard_ranges(), 1)
self.assert_container_listing([])
self.assert_container_object_count(0)
self.assert_container_listing(shard_1_objects)
self.assert_container_object_count(len(shard_1_objects))
# until sharder runs on that node to move the misplaced object to the
# second shard range
shard_part, shard_nodes_numbers = self.get_part_and_node_numbers(
shard_ranges[0])
self.sharders.once(additional_args='--partitions=%s' % shard_part,
number=misplaced_node['id'] + 1)
self.assert_container_listing(['alpha'])
self.assert_container_object_count(0) # root not yet updated
self.assert_container_listing(['alpha'] + shard_1_objects)
# root not yet updated
self.assert_container_object_count(len(shard_1_objects))
# run sharder to get root updated
self.run_sharders(shard_ranges[1])
self.assert_container_listing(['alpha'])
self.assert_container_object_count(1)
self.assert_container_listing(['alpha'] + shard_1_objects)
self.assert_container_object_count(len(shard_1_objects) + 1)
self.assertLengthEqual(self.get_container_shard_ranges(), 1)
# Now we have just one active shard, test a misplaced object moving
# from that shard to the root.
# run sharder on root to discover second shrink candidate
# delete most objects from second shard range and run sharder on root
# to discover second shrink candidate
self.delete_objects(shard_1_objects)
self.run_sharders(shard_ranges[1])
self.sharders.once(additional_args='--partitions=%s' % self.brain.part)
# then run sharder on the shard node to shrink it to root - note this
# moves alpha to the root db
shard_part, shard_nodes_numbers = self.get_part_and_node_numbers(
shard_ranges[1])
self.sharders.once(additional_args='--partitions=%s' % shard_part)
self.run_sharders(shard_ranges[1])
# now there are no active shards
self.assertFalse(self.get_container_shard_ranges())
@ -1836,6 +1842,8 @@ class TestContainerSharding(BaseTestContainerSharding):
self.assert_container_listing(['alpha'])
self.assert_container_object_count(1)
# until sharder runs on that node to move the misplaced object
shard_part, shard_nodes_numbers = self.get_part_and_node_numbers(
shard_ranges[1])
self.sharders.once(additional_args='--partitions=%s' % shard_part,
number=misplaced_node['id'] + 1)
self.assert_container_listing(['beta'])