系统允许的总锁数

SELECT
(SELECT setting::int FROM pg_settings WHERE name = 'max_locks_per_transaction') *
(SELECT setting::int FROM pg_settings WHERE name = 'max_connections') +
(SELECT setting::int FROM pg_settings WHERE name = 'max_prepared_transactions');

当锁大于上述数据

dynadot=# SELECT                         
count(    pid)
FROM pg_locks ;count 
-------563
(1 row)

就会出现

 ERROR: out of shared memory

一般是调大max_locks_per_transaction

参考下方的官方文档。

20.12. 锁管理

大多数会出现在“查询一个有很多子表的父表”这种情况，会有大量的锁。所以此时会报错。