[td-255] sleep before retry

src/client/src/tscServer.c

@@ -43,6 +43,14 @@ void tscUpdateSubscriptionProgress(void* sub, int64_t uid, TSKEY ts);
 void tscSaveSubscriptionProgress(void* sub);
 
 static int32_t minMsgSize() { return tsRpcHeadSize + 100; }
+static int32_t getWaitingTimeInterval(int32_t count) {
+  int32_t initial = 100; // 100 ms by default
+  if (count <= 1) {
+    return 0;
+  }
+
+  return initial * (2<<(count - 2));
+}
 
 static void tscSetDnodeEpSet(SSqlObj* pSql, SCMVgroupInfo* pVgroupInfo) {
   assert(pSql != NULL && pVgroupInfo != NULL && pVgroupInfo->numOfEps > 0);
@@ -288,6 +296,12 @@ void tscProcessMsgFromServer(SRpcMsg *rpcMsg, SRpcEpSet *pEpSet) {
     if (pSql->retry > pSql->maxRetry) {
       tscError("%p max retry %d reached, give up", pSql, pSql->maxRetry);
     } else {
+      // wait for a little bit moment and then retry
+      if (rpcMsg->code == TSDB_CODE_APP_NOT_READY || rpcMsg->code == TSDB_CODE_VND_INVALID_VGROUP_ID) {
+        int32_t duration = getWaitingTimeInterval(pSql->retry);
+        taosMsleep(duration);
+      }
+
       rpcMsg->code = tscRenewTableMeta(pSql, pTableMetaInfo->name);
 
       // if there is an error occurring, proceed to the following error handling procedure.