refactor(sync): add syncGetSnapshotMeta

include/libs/sync/sync.h

@@ -94,6 +94,10 @@ typedef struct SSnapshot {
   SyncIndex lastConfigIndex;
 } SSnapshot;
 
+typedef struct SSnapshotMeta {
+  SyncIndex lastConfigIndex;
+} SSnapshotMeta;
+
 typedef struct SSyncFSM {
   void* data;
 
@@ -191,6 +195,8 @@ bool        syncEnvIsStart();
 const char* syncStr(ESyncState state);
 bool        syncIsRestoreFinish(int64_t rid);
 
+int32_t syncGetSnapshotMeta(int64_t rid, struct SSnapshotMeta* sMeta);
+
 // to be moved to static
 void syncStartNormal(int64_t rid);
 void syncStartStandBy(int64_t rid);

source/libs/sync/inc/syncInt.h

@@ -157,6 +157,8 @@ typedef struct SSyncNode {
   SSyncSnapshotSender*   senders[TSDB_MAX_REPLICA];
   SSyncSnapshotReceiver* pNewNodeReceiver;
 
+  SSnapshotMeta sMeta;
+
 } SSyncNode;
 
 // open/close --------------

source/libs/sync/src/syncMain.c

@@ -214,6 +214,18 @@ bool syncIsRestoreFinish(int64_t rid) {
   return b;
 }
 
+int32_t syncGetSnapshotMeta(int64_t rid, struct SSnapshotMeta* sMeta) {
+  SSyncNode* pSyncNode = (SSyncNode*)taosAcquireRef(tsNodeRefId, rid);
+  if (pSyncNode == NULL) {
+    return -1;
+  }
+  assert(rid == pSyncNode->rid);
+  *sMeta = pSyncNode->sMeta;
+
+  taosReleaseRef(tsNodeRefId, pSyncNode->rid);
+  return 0;
+}
+
 const char* syncGetMyRoleStr(int64_t rid) {
   const char* s = syncUtilState2String(syncGetMyRole(rid));
   return s;
@@ -604,6 +616,9 @@ SSyncNode* syncNodeOpen(const SSyncInfo* pOldSyncInfo) {
   // start raft
   // syncNodeBecomeFollower(pSyncNode);
 
+  // snapshot meta
+  pSyncNode->sMeta.lastConfigIndex = -1;
+
   return pSyncNode;
 }