PolarDB为啥压500个现成就max_connections limit exceed？[阿里云PolarDB]

PolarDB为啥压500个现成就max_connections limit exceed？FATAL: `thread_run’ function failed: /usr/share/sysbench/oltp_common.lua:432: SQL error, errno = 10001, state = ‘HY000’: [16f13afd86801001][10.0.31.105:11312][sbtest]ERR-CODE: [PXC-4614][ERR_EXECUTE_ON_MYSQL] Error occurs when execute on GROUP ‘SBTEST_P00000_GROUP’ ATOM ‘dskey_sbtest_p00000_group#pxc-product-bsjw-dn-0#10.43.36.124-15782#sbtest_p00000’: ERR-CODE: [PXC-10001][ERR_X_PROTOCOL_CLIENT] XDataSource to admin@10.43.36.124:43782 Fatal error when fetch data: max_connections limit exceed
Error in my_thread_globalend(): 214 threads didn’t exit
参数模板没有应该走的默认值吧，但是我运行时有动态改过，而且运行时查询出来是2000，理论上应该没关系吧？