Implements the PostgresSQL timestamptz (aka timestamp with time zone) type.

Postgres strongly recommends using this type instead of the standard timestamps/datetimes without a time zone. Generally speaking, it is best practice to use the nanosecond-precision variant.

The basic reason timestamptz exists is to guarantee that the precise moment in time is stored as microseconds since January 1st, 2000 in UTC. This guarantee eliminates many time arithmetic problems, and ensures portability.

It does not actually store a timezone, in spite of the name. As far as Elixir/Ecto is concerned, it is always of type DateTime and set to UTC. Using this type ensures Postgres internally uses the same contract as Ecto's :utc_datetime, which is to always store DateTime in UTC. This is especially helpful if you need to do complex time arithmetic in SQL fragments, or build reports/materialized views that use localized time formatting.

Using this type ubiquitously in your schemas is particularly beneficial for consistency, and this is currently under consideration as a configuration option for the default datetime storage type.

attribute :timestamp, AshPostgres.Timestamptz
timestamps type: AshPostgres.Timestamptz

Alternatively, you can set up a shortname:

# config.exs
config :ash, :custom_types, timestamptz: AshPostgres.Timestamptz

After saving, you will need to run mix compile ash --force.

attribute :timestamp, :timestamptz
timestamps type: :timestamptz