refactor(sync): add syncBeginSnapshot, syncEndSnapshot

source/libs/sync/src/syncMain.c

@@ -297,10 +297,30 @@ int32_t syncBeginSnapshot(int64_t rid, int64_t lastApplyIndex) {
   ASSERT(rid == pSyncNode->rid);
   int32_t code = 0;
 
+  for (int32_t i = 0; i < pSyncNode->peersNum; ++i) {
+    int64_t matchIndex = syncIndexMgrGetIndex(pSyncNode->pMatchIndex, &(pSyncNode->peersId[i]));
+    if (lastApplyIndex > matchIndex) {
+      do {
+        char     host[64];
+        uint16_t port;
+        syncUtilU642Addr(pSyncNode->peersId[i].addr, host, sizeof(host), &port);
+        char logBuf[256];
+        snprintf(logBuf, sizeof(logBuf),
+                 "new-snapshot-index:%ld is greater than match-index:%ld of %s:%d, do not delete wal", lastApplyIndex,
+                 matchIndex, host, port);
+        syncNodeEventLog(pSyncNode, logBuf);
+      } while (0);
+
+      return 0;
+    }
+  }
+
   if (pSyncNode->replicaNum == 1) {
     SSyncLogStoreData* pData = pSyncNode->pLogStore->data;
     code = walBeginSnapshot(pData->pWal, lastApplyIndex);
   } else {
+    // calculate snapshot index
+
     SyncIndex snapshottingIndex = atomic_load_64(&pSyncNode->snapshottingIndex);
 
     if (snapshottingIndex == SYNC_INDEX_INVALID) {
@@ -310,7 +330,10 @@ int32_t syncBeginSnapshot(int64_t rid, int64_t lastApplyIndex) {
       code = walBeginSnapshot(pData->pWal, lastApplyIndex);
 
     } else {
-      sError("vgId:%d snapshotting index:%ld, lastApplyIndex:%ld", snapshottingIndex, lastApplyIndex);
+      char logBuf[256];
+      snprintf(logBuf, sizeof(logBuf), "snapshotting for %ld, do not delete wal for new-snapshot-index:%ld",
+               snapshottingIndex, lastApplyIndex);
+      syncNodeEventLog(pSyncNode, logBuf);
     }
   }
 
@@ -326,8 +349,13 @@ int32_t syncEndSnapshot(int64_t rid) {
   }
   ASSERT(rid == pSyncNode->rid);
 
-  SSyncLogStoreData* pData = pSyncNode->pLogStore->data;
-  int32_t            code = walEndSnapshot(pData->pWal);
+  int32_t code = 0;
+  if (atomic_load_64(&pSyncNode->snapshottingIndex) != SYNC_INDEX_INVALID) {
+    SSyncLogStoreData* pData = pSyncNode->pLogStore->data;
+    code = walEndSnapshot(pData->pWal);
+
+    atomic_store_64(&pSyncNode->snapshottingIndex, SYNC_INDEX_INVALID);
+  }
 
   taosReleaseRef(tsNodeRefId, pSyncNode->rid);
   return code;