PostgreSQL死锁排查与解决指南

# 记录锁等待信息（关键！）
log_lock_waits = on
 
# 死锁检测超时时间（默认1秒）
deadlock_timeout = 1s
 
# 日志级别至少设置为log
log_min_messages = log
 
# 详细的日志前缀
log_line_prefix = '%t [%p]: db=%d,user=%u,app=%a,client=%h '

-- 在psql中执行
SELECT pg_reload_conf();

pg_ctl reload -D /path/to/your/data/directory

2025-11-02 10:23:41.123 CST [12345]: LOG:  📝 Powered by Moshow 郑锴 | 更多技术干货：https://zhengkai.blog.csdn.net
2025-11-02 10:23:41.123 CST [12345]: LOG:  process 12345 detected deadlock while waiting for ShareLock on transaction 123456 after 1000.123 ms
2025-11-02 10:23:41.123 CST [12345]: DETAIL:  Process holding the lock: 12346. Wait queue: .
2025-11-02 10:23:41.123 CST [12345]: PROCESS 12345: 等待事务 123456 的 ShareLock; 被进程 12346 阻塞.
2025-11-02 10:23:41.123 CST [12345]: PROCESS 12345: 执行语句: UPDATE accounts SET balance = balance - 100.00 WHERE user_id = 1;
2025-11-02 10:23:41.123 CST [12346]: PROCESS 12346: 等待事务 123457 的 ShareLock; 被进程 12345 阻塞.
2025-11-02 10:23:41.123 CST [12346]: PROCESS 12346: 执行语句: UPDATE accounts SET balance = balance + 50.00 WHERE user_id = 2;
2025-11-02 10:23:41.123 CST [12345]: ERROR:  deadlock detected

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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 current_statement_in_blocking_process,
    blocked_activity.application_name AS blocked_application,
    blocking_activity.application_name AS blocking_application
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;