报错具体信息：

org.springframework.dao.DataAccessResourceFailureException:

### Error updating database. Cause: org.postgresql.util.PSQLException: An I/O error occurred while sending to the backend.

### The error may exist in file [C:\xxx\target\classes\mapper\examStu.xml]

### The error may involve examStu.BaseParameterMap

### The error occurred while setting parameters

### SQL: update examstu set submitstatus = 1, submittime = now() WHERE deleteflag = 0 and submitstatus = 0 and fk_paper is not null and endtime < to_timestamp(?, 'yyyy-mm-dd HH24:MI:SS')

### Cause: org.postgresql.util.PSQLException: An I/O error occurred while sending to the backend.

; An I/O error occurred while sending to the backend.; nested exception is org.postgresql.util.PSQLException: An I/O error occurred while sending to the backend.