例子：
长事务 30 min

select datname,usename,query,xact_start,now()-xact_start xact_duration,query_start,now()-query_start query_duration,state from pg_stat_activity where state<>
$$
idle
$$
 and (backend_xid is not null or backend_xmin is not null) and now()-xact_start > interval 
$$
30 min
$$
 order by xact_start;

2PC长事务 30 min

select name,statement,prepare_time,now()-prepare_time,parameter_types,from_sql from pg_prepared_statements where now()-prepare_time > interval 
$$
30 min
$$
 order by prepare_time;

https://blog.csdn.net/jackgo73/article/details/122700702