Models¶

The ActiveRecord is the default ORM in the Ruby community. We have introduced a macro that helps you to inject the behavior as other libraries do in the Rails ecosystem.

The `acts_as_hypertable` macro¶

You can declare a Rails model as a Hypertable by invoking the acts_as_hypertable macro. This macro extends your existing model with timescaledb-related functionality. model:

class Event < ActiveRecord::Base
  acts_as_hypertable
end

By default, ActsAsHypertable assumes a record's time_column is called created_at.

Options¶

If you are using a different time_column name, you can specify it as follows when invoking the acts_as_hypertable macro:

class Event < ActiveRecord::Base
  acts_as_hypertable time_column :timestamp
end

Chunks¶

To get all the chunks from a model's hypertable, you can use .chunks.

Event.chunks # => [#<Timescaledb::Chunk>, ...]

Warning

The chunks method is only available when you use the acts_as_hypertable macro. By default, the macro will define several scopes and class methods to help you to inspect timescaledb metadata like chunks and hypertable metadata. You can disable this behavior by passing skip_association_scopes:

class Event < ActiveRecord::Base
  acts_as_hypertable skip_association_scopes: true
end
Event.chunks # => NoMethodError

Hypertable metadata¶

To get the models' hypertable metadata, you can use .hypertable.

Event.hypertable # => #<Timescaledb::Hypertable>

To get hypertable metadata for all hypertables: Timescaledb.hypertables.

Compression Settings¶

Compression settings are accessible through the hypertable.

Event.hypertable.compression_settings # => [#<Timescaledb::CompressionSettings>, ...]

To get compression settings for all hypertables: Timescaledb.compression_settings.

Scopes¶

When you enable ActsAsHypertable on your model, we include a few default scopes. They are:

Scope name	What they return
`Model.previous_month`	Records created in the previous month
`Model.previous_week`	Records created in the previous week
`Model.this_month`	Records created this month
`Model.this_week`	Records created this week
`Model.yesterday`	Records created yesterday
`Model.today`	Records created today
`Model.last_hour`	Records created in the last hour

All time-related scopes respect your application's timezone.

Warning

To disable these scopes, pass skip_default_scopes: true to the acts_as_hypertable macro.

class Event < ActiveRecord::Base
  acts_as_hypertable skip_default_scopes: true
end

Scenic integration¶

The Scenic gem is easy to manage database view definitions for a Rails application. Unfortunately, TimescaleDB's continuous aggregates are more complex than regular PostgreSQL views, and the schema dumper included with Scenic can't dump a complete definition.

This gem automatically configures Scenic to use a Timescaledb::Scenic::Adapter. which will correctly handle schema dumping.