[ISSUE #325] Fix unable to auto recover after follower isolation

openmessaging · Dec 14, 2024 · 9d791bc · 9d791bc
1 parent d054548
commit 9d791bc
Showing 1 changed file with 9 additions and 7 deletions.
diff --git a/dledger/src/main/java/io/openmessaging/storage/dledger/DLedgerLeaderElector.java b/dledger/src/main/java/io/openmessaging/storage/dledger/DLedgerLeaderElector.java
@@ -192,7 +192,7 @@ public void changeRoleToFollower(long term, String leaderId) {
         handleRoleChange(term, MemberState.Role.FOLLOWER);
     }
 
-    public CompletableFuture<VoteResponse> handleVote(VoteRequest request, boolean self) {
+ public CompletableFuture<VoteResponse> handleVote(VoteRequest request, boolean self) {
         //hold the lock to get the latest term, leaderId, ledgerEndIndex
         synchronized (memberState) {
             if (!memberState.isPeerMember(request.getLeaderId())) {
@@ -204,6 +204,14 @@ public CompletableFuture<VoteResponse> handleVote(VoteRequest request, boolean s
                 return CompletableFuture.completedFuture(new VoteResponse(request).term(memberState.currTerm()).voteResult(VoteResponse.RESULT.REJECT_UNEXPECTED_LEADER));
             }
 
+            if (request.getTerm() > memberState.currTerm()) {
+                //stepped down by larger term
+                changeRoleToCandidate(request.getTerm());
+                needIncreaseTermImmediately = true;
+                //only can handleVote when the term is consistent
+                return CompletableFuture.completedFuture(new VoteResponse(request).term(memberState.currTerm()).voteResult(VoteResponse.RESULT.REJECT_TERM_NOT_READY));
+            }
+
             if (request.getLedgerEndTerm() < memberState.getLedgerEndTerm()) {
                 return CompletableFuture.completedFuture(new VoteResponse(request).term(memberState.currTerm()).voteResult(VoteResponse.RESULT.REJECT_EXPIRED_LEDGER_TERM));
             } else if (request.getLedgerEndTerm() == memberState.getLedgerEndTerm() && request.getLedgerEndIndex() < memberState.getLedgerEndIndex()) {
@@ -224,12 +232,6 @@ public CompletableFuture<VoteResponse> handleVote(VoteRequest request, boolean s
                         return CompletableFuture.completedFuture(new VoteResponse(request).term(memberState.currTerm()).voteResult(VoteResponse.RESULT.REJECT_ALREADY_VOTED));
                     }
                 }
-            } else {
-                //stepped down by larger term
-                changeRoleToCandidate(request.getTerm());
-                needIncreaseTermImmediately = true;
-                //only can handleVote when the term is consistent
-                return CompletableFuture.completedFuture(new VoteResponse(request).term(memberState.currTerm()).voteResult(VoteResponse.RESULT.REJECT_TERM_NOT_READY));
             }
 
             if (request.getTerm() < memberState.getLedgerEndTerm()) {