Fix ps cache is invalid when calling cache_evict_all_ps

src/sql/plan_cache/ob_plan_cache_manager.cpp

@@ -581,8 +581,8 @@ int ObPlanCacheManager::revert_ps_cache(const uint64_t& tenant_id)
   if (OB_SUCCESS == tmp_ret && NULL != ppc) {
     SQL_PC_LOG(INFO, "plan_cache_manager revert ps plan cache", "pc ref_count", ppc->get_ref_count(), K(tenant_id));
     // cancel scheduled task
-    ppc->set_valid(false);
     ppc->dec_ref_count();
+    ppc->set_valid(false);
   } else if (OB_HASH_NOT_EXIST == tmp_ret) {  // maybe erase by other thread
     SQL_PC_LOG(INFO, "PS Plan Cache not exist", K(tenant_id));
   } else {