postgresql 查询锁表

如果你需要查询 PostgreSQL 中的锁表信息，可以使用以下 SQL 查询语句：

SELECT blocked_locks.pid AS blocked_pid,
       blocked_activity.usename AS blocked_user,
       blocking_locks.pid AS blocking_pid,
       blocking_activity.usename AS blocking_user,
       blocked_activity.query AS blocked_statement,
       blocking_activity.query AS blocking_statement
FROM pg_catalog.pg_locks blocked_locks
JOIN pg_catalog.pg_stat_activity blocked_activity ON blocked_activity.pid = blocked_locks.pid
JOIN pg_catalog.pg_locks blocking_locks ON blocking_locks.locktype = blocked_locks.locktype
                                        AND blocking_locks.DATABASE IS NOT DISTINCT FROM blocked_locks.DATABASE
                                        AND blocking_locks.relation IS NOT DISTINCT FROM blocked_locks.relation
                                        AND blocking_locks.page IS NOT DISTINCT FROM blocked_locks.page
                                        AND blocking_locks.tuple IS NOT DISTINCT FROM blocked_locks.tuple
                                        AND blocking_locks.virtualxid IS NOT DISTINCT FROM blocked_locks.virtualxid
                                        AND blocking_locks.transactionid IS NOT DISTINCT FROM blocked_locks.transactionid
                                        AND blocking_locks.classid IS NOT DISTINCT FROM blocked_locks.classid
                                        AND blocking_locks.objid IS NOT DISTINCT FROM blocked_locks.objid
                                        AND blocking_locks.objsubid IS NOT DISTINCT FROM blocked_locks.objsubid
                                        AND blocking_locks.pid != blocked_locks.pid
JOIN pg_catalog.pg_stat_activity blocking_activity ON blocking_activity.pid = blocking_locks.pid
WHERE NOT blocked_locks.GRANTED;

这个查询语句将返回所有被阻塞的进程及其对应的阻塞进程的信息。其中，blocked_pid 和 blocked_user 分别表示被阻塞进程的 PID 和用户名，blocking_pid 和 blocking_user 分别表示阻塞进程的 PID 和用户名，blocked_statement 和 blocking_statement 分别表示被阻塞进程和阻塞进程正在执行的 SQL 语句。