使用 pg_controldata 查看 Database system identifier
$ /usr/pgsql-10/bin/pg_controldata -D /var/lib/pgsql/10/data/
pg_control version number: 1002
Catalog version number: 201707211
Database system identifier: 6571787082216241690
Database cluster state: in production
pg_control last modified: Thu 05 Jul 2018 05:17:31 PM CST
Latest checkpoint location: 0/16D3DE0
Prior checkpoint location: 0/16D3D00
Latest checkpoint's REDO location: 0/16D3DA8
Latest checkpoint's REDO WAL file: 000000010000000000000001执行下面sql
peiybdb=# select version();
version
---------------------------------------------------------------------------------------------------------
PostgreSQL 10.4 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-28), 64-bit
(1 row)
peiybdb=# SELECT to_timestamp(((6571787082216241690>>32) &(2^32 -1)::bigint));
to_timestamp
------------------------
2018-06-27 23:30:16+08
(1 row)