PostgreSQL 11 Shared Memory Error: could not open shared memory segment "/PostgreSQL.XXXXXXXX": No such file or directory

Question

共享内存文件在 Postgres 11 中被删除了一段时间（约 15 小时）

2019-07-09 08:46:41 CDT [] [6723]: [1-1] user=,db=,e=58P01 ERROR:  could not open shared memory segment "/PostgreSQL.291691635": No such file or directory
2019-07-09 08:46:41 CDT [] [6722]: [1-1] user=,db=,e=58P01 ERROR:  could not open shared memory segment "/PostgreSQL.291691635": No such file or directory
2019-07-09 08:46:41 CDT [10.40.0.204(60550)] [13880]: [1-1] user=user_name,db=db_name,e=58P01 ERROR:  could not open shared memory segment "/PostgreSQL.291691635": No such file or directory
2019-07-09 08:46:41 CDT [10.40.0.204(60550)] [13880]: [2-1] user=user_name,db=db_name,e=58P01 CONTEXT:  parallel worker
2019-07-09 08:46:41 CDT [10.40.0.204(60550)] [13880]: [3-1] user=user_name,db=db_name,e=58P01 STATEMENT:  WITH overall_reviewed AS (SQL Query)

GCP 虚拟机配置

CPU: 4
RAM: 16 GB
 OS: Ubuntu 18.04.1 LTS

内核共享内存设置shared

kernel.shmmax=8589934592
kernel.shmall=2097152

postgresql.config

max_connections = 500
shared_buffers = 4GB
effective_cache_size = 12GB
maintenance_work_mem = 1GB
checkpoint_completion_target = 0.7
wal_buffers = 16MB
default_statistics_target = 100
random_page_cost = 1.1
effective_io_concurrency = 200
work_mem = 4194kB
min_wal_size = 1GB
max_wal_size = 2GB
max_worker_processes = 4
max_parallel_workers_per_gather = 2
max_parallel_workers = 4

启动期间：无errors/warnings 大约 15 小时后，一些共享内存文件被删除，我怀疑是否有任何其他进程删除“/dev/shm”中的文件？

不确定根本原因是什么

Answer 1

在 postgresql.conf 中制作 dynamic_shared_memory_type = none 确实解决了问题。

Answer 2

在 Ubuntu 18.04 和 PostgreSQL 11 上遇到了同样的问题，经过更多研究后，我找到了适合我们的解决方案。当备份用户（与PG服务用户相同的用户）登录系统时发生错误。下面的Link描述的是/dev/shm下的存储在用户登录系统（同一用户）时被删除。所以我们的解决方案是更改以下内容：

/etc/systemd/logind.conf

添加了行

RemoveIPC=no

并重启服务

systemctl restart systemd-logind.service

来源：

https://www.postgresql-archive.org/systemd-deletes-shared-memory-segment-in-dev-shm-Postgresql-NNNNNN-td5883507.html

https://superuser.com/questions/1117764/why-are-the-contents-of-dev-shm-is-being-removed-automatically

Answer 3

遇到同样的问题.....当我用相同的用户帐户打开两个 sqldeveloper 时，其中一个是我的远程会话，我完全忘记了关闭会话。

我正在做一些聚合运算符，例如 count(*) 或 max(...)，两者都出现错误。并且错误类似：

ERROR: could not open shared memory segment "/PostgreSQL.798235387": No such file or directory Where: parallel worker

解决方案？我杀了远程会话.... XD 生活再次平静幸福:D

PostgreSQL 11 Shared Memory Error: could not open shared memory segment "/PostgreSQL.XXXXXXXX": No such file or directory

PostgreSQL 11 Shared Memory Error: could not open shared memory segment "/PostgreSQL.XXXXXXXX": No such file or directory

postgresql

systemd

ubuntu-18.04

postgresql-11