etcdserver: remove possibly compacted entry look-up #7513
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
heyitsanthony
approved these changes
Mar 15, 2017
etcdserver/server.go
Outdated
| @@ -1254,8 +1257,9 @@ func (s *EtcdServer) sendMergedSnap(merged snap.Message) { | |||
| // apply takes entries received from Raft (after it has been committed) and | |||
| // applies them to the current state of the EtcdServer. | |||
| // The given entries should not be empty. | |||
| func (s *EtcdServer) apply(es []raftpb.Entry, confState *raftpb.ConfState) (uint64, bool) { | |||
| var applied uint64 | |||
| func (s *EtcdServer) apply(es []raftpb.Entry, confState *raftpb.ConfState) (uint64, uint64, bool) { | |||
There was a problem hiding this comment.
func (s *EtcdServer) apply(es []raftpb.Entry, confState *raftpb.ConfState) (appliedt uint64, appliedi uint64, shouldStop bool) { to make the return values clearer?
|
lgtm defer to @xiang90 |
gyuho
force-pushed
the
raft-applied-term
branch
from
aa157f7
to
8671fb8
Compare
xiang90
reviewed
Mar 15, 2017
etcdserver/server.go
Outdated
| } | ||
| return applied, shouldstop | ||
| return |
|
LGTM. Great analysis. |
Fix etcd-io#7470. This patch removes unnecessary term look-up in 'createMergedSnapshotMessage', which can trigger panic if raft entry at etcdProgress.appliedi got compacted by subsequent 'MsgSnap' messages--if a follower is being (in this case, network latency spikes), it could receive subsequent 'MsgSnap' requests from leader. etcd server-side 'applyAll' routine and raft's Ready processing routine becomes asynchronous after raft entries are persisted. And given that raft Ready routine takes less time to finish, it is possible that second 'MsgSnap' is being handled, while the slow 'applyAll' is still processing the first(old) 'MsgSnap'. Then raft Ready routine can compact the log entries at future index to 'applyAll'. That is how 'createMergedSnapshotMessage' tried to look up raft term with outdated etcdProgress.appliedi. Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>
gyuho
force-pushed
the
raft-applied-term
branch
from
8671fb8
to
80c10e1
Compare
Codecov Report
@@ Coverage Diff @@
## master #7513 +/- ##
=========================================
Coverage ? 70.25%
=========================================
Files ? 320
Lines ? 26203
Branches ? 0
=========================================
Hits ? 18408
Misses ? 6338
Partials ? 1457
Continue to review full report at Codecov.
|
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fix #7470.
This patch removes unnecessary term look-up in
'createMergedSnapshotMessage', which can trigger panic
if raft entry at etcdProgress.appliedi got compacted
by subsequent 'MsgSnap' messages--if a follower is
being (in this case, network latency spikes) slow, it
could receive subsequent 'MsgSnap' requests from leader.
etcd server-side 'applyAll' routine and raft's Ready
processing routine becomes asynchronous after raft
entries are persisted. And given that raft Ready routine
takes less time to finish, it is possible that second
'MsgSnap' is being handled, while the slow 'applyAll'
is still processing the first(old) 'MsgSnap'. Then raft
Ready routine can compact the log entries at future
index to 'applyAll'. That is how 'createMergedSnapshotMessage'
tried to look up raft term with outdated etcdProgress.appliedi.