Get database creation date on PostgreSQL

I completely agree with Craig Ringer (excellent answer!)... but for my purposes , this is good enough:

SELECT (pg_stat_file('base/'||oid ||'/PG_VERSION')).modification, datname FROM pg_database;

Simple and clean (but superuser).

There is no built-in record of the PostgreSQL database creation time in the system. All approaches that rely on file system creation/modification times can produce wrong answers.

For example, if you pg_basebackup a replica node then fail over to it, the creation time will appear to be the time the replica was created. pg_basebackup doesn't preserve file creation/modification times because they're generally not considered relevant for operation of the database system.

The only reliable way to get the database creation time is to create a 1-row table with the creation time in it when you create the database, then set permissions / add a trigger so it rejects updates.

If you don't mind the risk of a wrong answer where the creation time is reported as being much newer than it really was, you can look at the timestamp of the base/[dboid]/PG_VERSION file. @Bob showed a useful way to do that.

Also alternative solution:

1. Find database OID:

postgres=# select oid,datname from pg_database where datname='bars_paidserv';-[ RECORD 1 ]----------oid     | 5137290datname | bars_paidserv

2. Go to database datatfiles (you can find your directory by executing show data_directory):

cd /var/lib/postgresql/9.6/main/base

3. list PG_VERSION file in your OID:

postgres@test-rp:~/9.6/main/base$ ls -l 5137290/PG_VERSION-rw------- 1 postgres postgres 4 Jan 29 12:34 5137290/PG_VERSION

i.e. my database bars_paidserv with OID 5137290 was created on Jan 29.