[postgresql] How do I get the current timezone name in Postgres 9.3?

I want to get the current timezone name. What I already achieved is to get the utc_offset / the timezone abbreviation via:

SELECT * FROM pg_timezone_names WHERE abbrev = current_setting('TIMEZONE')

This gives me all Continent / Capital combinations for this timezone but not the exact timezone. For example I get:

Europe/Amsterdam
Europe/Berlin

The server is in Berlin and I want to get the timezone name of the server.

The problem I have with CET that it is always UTC+01:00 and does not account for DST iirc.

I don't think this is possible using PostgreSQL alone in the most general case. When you install PostgreSQL, you pick a time zone. I'm pretty sure the default is to use the operating system's timezone. That will usually be reflected in postgresql.conf as the value of the parameter "timezone". But the value ends up as "localtime". You can see this setting with the SQL statement.

show timezone;

But if you change the timezone in postgresql.conf to something like "Europe/Berlin", then show timezone; will return that value instead of "localtime".

So I think your solution will involve setting "timezone" in postgresql.conf to an explicit value rather than the default "localtime".

This may or may not help you address your problem, OP, but to get the timezone of the current server relative to UTC (UT1, technically), do:

SELECT EXTRACT(TIMEZONE FROM now())/3600.0;

The above works by extracting the UT1-relative offset in minutes, and then converting it to hours using the factor of 3600 secs/hour.

Example:

SET SESSION timezone TO 'Asia/Kabul';
SELECT EXTRACT(TIMEZONE FROM now())/3600.0;
-- output: 4.5 (as of the writing of this post)

(docs).

See this answer: Source

If timezone is not specified in postgresql.conf or as a server command-line option, the server attempts to use the value of the TZ environment variable as the default time zone. If TZ is not defined or is not any of the time zone names known to PostgreSQL, the server attempts to determine the operating system's default time zone by checking the behavior of the C library function localtime(). The default time zone is selected as the closest match among PostgreSQL's known time zones. (These rules are also used to choose the default value of log_timezone, if not specified.) source

This means that if you do not define a timezone, the server attempts to determine the operating system's default time zone by checking the behavior of the C library function localtime().

If timezone is not specified in postgresql.conf or as a server command-line option, the server attempts to use the value of the TZ environment variable as the default time zone.

It seems to have the System's timezone to be set is possible indeed.

Get the OS local time zone from the shell. In psql:

=> \! date +%Z

It seems to work fine in Postgresql 9.5:

SELECT current_setting('TIMEZONE');

You can access the timezone by the following script:

SELECT * FROM pg_timezone_names WHERE name = current_setting('TIMEZONE');

• current_setting('TIMEZONE') will give you Continent / Capital information of settings
• pg_timezone_names The view pg_timezone_names provides a list of time zone names that are recognized by SET TIMEZONE, along with their associated abbreviations, UTC offsets, and daylight-savings status.
• name column in a view (pg_timezone_names) is time zone name.

output will be :

name- Europe/Berlin, 
abbrev - CET, 
utc_offset- 01:00:00, 
is_dst- false