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Posted to dev@ratis.apache.org by GitBox <gi...@apache.org> on 2021/01/05 08:20:31 UTC
[GitHub] [incubator-ratis] runzhiwang opened a new pull request #378: RATIS-1268. Fix leader can not vote for candidate
runzhiwang opened a new pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378
## What changes were proposed in this pull request?
**What's the problem ?**
For example, when s0 is leader, and s1 askForVote, in the first rpc of askForVote, s0 can not vote for s1, even though s1's log catch up. When s1 askForVote the second time, s0 has become follower in the first askForVote, so s0 can vote for s1, waste one rpc call.
**What's the reason ?**
As the following code shows, when s0 is leader, `role.getFollowerState().orElse(null)` should return null,
then can not pass check `if (fs != null && candidate != null)` because fs is null, so s0 can not vote for s1.
```
FollowerState fs = role.getFollowerState().orElse(null);
if (shouldWithholdVotes(candidateTerm)) {
...
} else if (state.recognizeCandidate(candidateId, candidateTerm)) {
final boolean termUpdated = changeToFollower(candidateTerm, true, "recognizeCandidate:" + candidateId);
RaftPeer candidate = getRaftConf().getPeer(candidateId);
if (fs != null && candidate != null) {
...
}
```
**How to fix ?**
After leader `final boolean termUpdated = changeToFollower(candidateTerm, true, "recognizeCandidate:" + candidateId);`, we can get fs again.
## What is the link to the Apache JIRA
https://issues.apache.org/jira/browse/RATIS-1268
## How was this patch tested?
no need to add new ut.
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[GitHub] [incubator-ratis] runzhiwang closed pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
runzhiwang closed pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378
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[GitHub] [incubator-ratis] runzhiwang commented on pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
runzhiwang commented on pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378#issuecomment-754469273
> I somehow have overlooked this pull request.
@szetszwo Thanks for review. It does not matter.
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[GitHub] [incubator-ratis] runzhiwang commented on a change in pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
runzhiwang commented on a change in pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378#discussion_r551763473
##########
File path: ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java
##########
@@ -1047,13 +1047,18 @@ private RequestVoteReplyProto requestVote(
synchronized (this) {
// Check life cycle state again to avoid the PAUSING/PAUSED state.
assertLifeCycleState(LifeCycle.States.RUNNING);
- final FollowerState fs = role.getFollowerState().orElse(null);
+ FollowerState fs = role.getFollowerState().orElse(null);
if (shouldWithholdVotes(candidateTerm)) {
LOG.info("{}-{}: Withhold vote from candidate {} with term {}. State: leader={}, term={}, lastRpcElapsed={}",
getMemberId(), role, candidateId, candidateTerm, state.getLeaderId(), state.getCurrentTerm(),
fs != null? fs.getLastRpcTime().elapsedTimeMs() + "ms": null);
} else if (state.recognizeCandidate(candidateId, candidateTerm)) {
final boolean termUpdated = changeToFollower(candidateTerm, true, "recognizeCandidate:" + candidateId);
+ if (fs == null) {
Review comment:
@lokeshj1703 Thanks for review. I have updated the patch.
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[GitHub] [incubator-ratis] lokeshj1703 closed pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
lokeshj1703 closed pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378
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[GitHub] [incubator-ratis] runzhiwang commented on pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
runzhiwang commented on pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378#issuecomment-754558533
@lokeshj1703 @szetszwo Thanks for review.
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[GitHub] [incubator-ratis] lokeshj1703 commented on pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
lokeshj1703 commented on pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378#issuecomment-754531751
@runzhiwang Thanks for the contribution! @szetszwo Thanks for the review! I have committed the PR to master branch.
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[GitHub] [incubator-ratis] runzhiwang closed pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
runzhiwang closed pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378
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[GitHub] [incubator-ratis] lokeshj1703 commented on a change in pull request #378: RATIS-1268. Fix leader can not vote for candidate
Posted by GitBox <gi...@apache.org>.
lokeshj1703 commented on a change in pull request #378:
URL: https://github.com/apache/incubator-ratis/pull/378#discussion_r551758951
##########
File path: ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java
##########
@@ -1047,13 +1047,18 @@ private RequestVoteReplyProto requestVote(
synchronized (this) {
// Check life cycle state again to avoid the PAUSING/PAUSED state.
assertLifeCycleState(LifeCycle.States.RUNNING);
- final FollowerState fs = role.getFollowerState().orElse(null);
+ FollowerState fs = role.getFollowerState().orElse(null);
if (shouldWithholdVotes(candidateTerm)) {
LOG.info("{}-{}: Withhold vote from candidate {} with term {}. State: leader={}, term={}, lastRpcElapsed={}",
getMemberId(), role, candidateId, candidateTerm, state.getLeaderId(), state.getCurrentTerm(),
fs != null? fs.getLastRpcTime().elapsedTimeMs() + "ms": null);
} else if (state.recognizeCandidate(candidateId, candidateTerm)) {
final boolean termUpdated = changeToFollower(candidateTerm, true, "recognizeCandidate:" + candidateId);
+ if (fs == null) {
Review comment:
I think we can remove the if condition here and call `fs = role.getFollowerState().orElse(null);` always
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