I'm running PostgreSQL as a Docker container (postgres:14.2).
I see the system timezone is set to UTC.
I'm trying to understand the impact of changing the timezone config of PostgreSQL.
If I ran multiple instances on a single host, and changed the timezone for 1 instance (via .conf), would all other instances be affected?
Or can each instance's timezone be configured separately?
Can a separate timezone be configured per schema?
Output from Docker container:
postgres#55f0148bcd87:~$ date
Mon Nov 28 17:55:35 UTC 2022
postgres#55f0148bcd87:~$ cat /etc/timezone
Etc/UTC
cat data/postgresql.conf:
timezone = 'Etc/UTC'
Each cluster (instance) is independent and has its own settings. The setting of timezone for a cluster is the default value for connections to databases in the cluster, but each database session should override that setting with the value for the time zone that applies to that individual database session.
Related
I'm using AWS DMS 3.4.6 to migrate a PostgreSQL 13.6 database to another PostgreSQL 13.6 database, both in AWS RDS.
One particular column in my database is a timestamp with time zone.
The 'timezone' property in the parameter groups for each database is set to 'GB'.
In my source database, I have the following value in my column:
2016-11-08 09:44:49.704142+00
This is migrated to the target database as:
2016-11-08 10:44:49.704142+00
The hour value is 1 hour greater than it should be.
In fact, this happens for all timestamps that would actually be GMT as opposed to BST. All BST timestamps migrate successfully.
What's happening?
After some reading of the AWS DMS docs, it became clear that migration of the timestamp-with-time-zone type for PostgreSQL isn't fully supported (although it's not clear precisely what should work and what shouldn't).
As I know that PostgreSQL stores these types as UTC, I decided to try setting the target database 'timezone' property (in the parameter group for the AWS RDS PostgreSQL db) to 'UTC' instead of 'GB'. This resulted in a correct migration. After completing the migration I changed the 'timezone' property for the target to be 'GB'. This now resulted in the stored 'UTC' values correctly displaying on selection for both GMT and BST date-time values.
I need to permanently change my postgreSQL db timezone from AEST to UTC, the instance is on AWS rds.
On my AWS RDS postgreSQL parameter group, the timezone shows UTC but when i run
show timezone; it returns my local time zone which is AEST
the sql SET TIMEZONE='UTC'; only change the session, so what's the right way to change the timezone to UTC permanently?
this link shows changing the parameter group value should work? https://aws.amazon.com/premiumsupport/knowledge-center/rds-change-time-zone/
thanks
A "source" of 'client' means that when your client connects, it sets the timezone it wants to use. This will override anything you do globally and permanently on the database side, as the client can always change their own setting for this.
If you tell us what your client is and how it is configured, someone may be able to help you change this behavior. For example if it is a libpq-based client, then having the PGTZ environment variable set will cause this behavior.
I'd like to know how to permanently change the timezone on postgresql -- using set timezone TO 'UTC' only changes it in current session, upon restarting it's back to my region timezone. If i change the postgresql.config file under data to:
datestyle = 'iso, dmy'
#intervalstyle = 'postgres'
timezone = 'UTC'
#timezone_abbreviations = 'Default'
Even if i stop the postgresql-x64-12 service, save the file, and restart service, it goes back to my region timezone afterwards.
Thank you!
The documentation says:
The TimeZone configuration parameter can be set in the file postgresql.conf, or in any of the other standard ways described in Chapter 19. There are also some special ways to set it:
The SQL command SET TIME ZONE sets the time zone for the session. This is an alternative spelling of SET TIMEZONE TO with a more SQL-spec-compatible syntax.
The PGTZ environment variable is used by libpq clients to send a SET TIME ZONE command to the server upon connection.
So either you changed the value in a wrong postgresql.conf, or you have the PGTZ environment variable set on the client side.
Another alternative is a SET TIME ZONE command in the .psqlrc file.
I am trying to change the RDS timezone to UTC,
I'm using an SQL Client called DBeaver
I tried the following two commands -
1. Configuration Parameter Name -
SET timezone TO 'UTC';
and
2. Standard SQL Command -
SET TIME ZONE 'UTC';
But the select now(); command still doesn't return the UTC time
I am referring this answer -
postgres default timezone
Tried the following -
echo $PGTZ
SET TIME ZONE 'UTC';
ALTER DATABASE your_db_name SET timezone TO 'UTC';
Maybe you are using a connection pool, and session settings get cleared when the session returns to the pool.
You could try something like
ALTER ROLE your_user SET timezone = 'UTC';
You must reconnect for this to take effect.
Also, check if the environment variable PGTZ is set in your environment. It will override the database settings.
If all that doesn't do the trick, consider the possibility that the server's time is off.
I have a timestamp column 'submitted_on' with default as now().
I have set the heroku TZ to my zone and added a php user ini with the same timezone.
But the database is still using UTC timezone. I see this when I ran this sql:
show timezone;
Is there a fix? Or this is how heroku databases work? Also I'm using free dynos.
Setting a TZ config var only affects the Dynos environment, as the database is located on a different machine, it has no effect.
Generally speaking, you should always keep servers clocks running on UTC, store all times in UTC, and perform any timezone/locale changes in your application framework.
The parameter timezone is determined when the database cluster is created.
You can either change the value in postgresql.conf, or you can use ALTER SYSTEM as a superuser to change the value.
I don't know if Heroku allows you either of these options.