From b42c963a5f7085b7dac21076de7996a33d187ce2 Mon Sep 17 00:00:00 2001
From: Minghao Li <castermode@gmail.com>
Date: Thu, 16 Jun 2022 20:08:27 +0800
Subject: [PATCH] fix(sync): fake match when prevLogIndex less than commitIndex

---
 source/libs/sync/src/syncAppendEntries.c | 26 +++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/source/libs/sync/src/syncAppendEntries.c b/source/libs/sync/src/syncAppendEntries.c
index 4ebd279668..7a4edb668a 100644
--- a/source/libs/sync/src/syncAppendEntries.c
+++ b/source/libs/sync/src/syncAppendEntries.c
@@ -880,13 +880,14 @@ int32_t syncNodeOnAppendEntriesSnapshotCb(SSyncNode* ths, SyncAppendEntries* pMs
     }
   } while (0);
 
-  // fake match
+  // fake match2
   //
   // condition1:
   // preIndex <= my commit index
   //
   // operation:
-  // match my commit index
+  // if hasAppendEntries && pMsg->prevLogIndex == ths->commitIndex, append entry
+  // match my-commit-index or my-commit-index + 1
   // no operation on log
   do {
     bool condition = (pMsg->term == ths->pRaftStore->currentTerm) && (ths->state == TAOS_SYNC_STATE_FOLLOWER) &&
@@ -895,6 +896,25 @@ int32_t syncNodeOnAppendEntriesSnapshotCb(SSyncNode* ths, SyncAppendEntries* pMs
       sTrace("recv SyncAppendEntries, fake match2, msg-prevLogIndex:%ld, my-commitIndex:%ld", pMsg->prevLogIndex,
              ths->commitIndex);
 
+      SyncIndex matchIndex = ths->commitIndex;
+      bool      hasAppendEntries = pMsg->dataLen > 0;
+      if (hasAppendEntries && pMsg->prevLogIndex == ths->commitIndex) {
+        // append entry
+        SSyncRaftEntry* pAppendEntry = syncEntryDeserialize(pMsg->data, pMsg->dataLen);
+        ASSERT(pAppendEntry != NULL);
+
+        code = ths->pLogStore->syncLogAppendEntry(ths->pLogStore, pAppendEntry);
+        ASSERT(code == 0);
+
+        // pre commit
+        code = syncNodePreCommit(ths, pAppendEntry);
+        ASSERT(code == 0);
+
+        matchIndex = pMsg->prevLogIndex + 1;
+
+        syncEntryDestory(pAppendEntry);
+      }
+
       // prepare response msg
       SyncAppendEntriesReply* pReply = syncAppendEntriesReplyBuild(ths->vgId);
       pReply->srcId = ths->myRaftId;
@@ -902,7 +922,7 @@ int32_t syncNodeOnAppendEntriesSnapshotCb(SSyncNode* ths, SyncAppendEntries* pMs
       pReply->term = ths->pRaftStore->currentTerm;
       pReply->privateTerm = ths->pNewNodeReceiver->privateTerm;
       pReply->success = true;
-      pReply->matchIndex = ths->commitIndex;
+      pReply->matchIndex = matchIndex;
 
       // send response
       SRpcMsg rpcMsg;
-- 
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