Clickhouse::Activerecord

A Ruby database ActiveRecord driver for ClickHouse. Support Rails >= 5.2. Support ClickHouse version from 20.9 LTS.

Installation

Add this line to your application's Gemfile:

gem 'clickhouse-activerecord'

And then execute:

$ bundle

Or install it yourself as:

$ gem install clickhouse-activerecord

Available database connection parameters

default: &default
  adapter: clickhouse
  database: database
  host: localhost
  port: 8123
  username: username
  password: password
  ssl: true # optional for using ssl connection
  debug: true # use for showing in to log technical information
  migrations_paths: db/clickhouse # optional, default: db/migrate_clickhouse
  cluster_name: 'cluster_name' # optional for creating tables in cluster 
  replica_name: '{replica}' # replica macros name, optional for creating replicated tables

Alternatively if you wish to pass a custom Net::HTTP transport (or any other object which supports a .post() function with the same parameters as Net::HTTP's), you can do this directly instead of specifying host/port/ssl:

class ActionView < ActiveRecord::Base
  establish_connection(
    adapter: 'clickhouse',
    database: 'database',
    connection: Net::HTTP.start('http://example.org', 8123)
  )
end

Usage in Rails 5

Add your database.yml connection information with postfix _clickhouse for you environment:

development_clickhouse:
  adapter: clickhouse
  database: database

Add to your model:

class Action < ActiveRecord::Base
  establish_connection "#{Rails.env}_clickhouse".to_sym
end

For materialized view model add:

class ActionView < ActiveRecord::Base
  establish_connection "#{Rails.env}_clickhouse".to_sym
  self.is_view = true
end

Or global connection:

development:
  adapter: clickhouse
  database: database

Usage in Rails 6 with second database

Add your database.yml connection information for you environment:

development:
  primary:
    ...
    
  clickhouse:
    adapter: clickhouse
    database: database

Connection Multiple Databases with Active Record or short example:

class Action < ActiveRecord::Base
  connects_to database: { writing: :clickhouse, reading: :clickhouse }
end

Rake tasks

Note! For Rails 6 you can use default rake tasks if you configure migrations_paths in your database.yml, for example: rake db:migrate

Create / drop / purge / reset database:

$ rake clickhouse:create
$ rake clickhouse:drop
$ rake clickhouse:purge
$ rake clickhouse:reset

Prepare system tables for rails:

$ rake clickhouse:prepare_schema_migration_table
$ rake clickhouse:prepare_internal_metadata_table

Migration:

$ rails g clickhouse_migration MIGRATION_NAME COLUMNS
$ rake clickhouse:migrate
$ rake clickhouse:rollback

Dump / Load for multiple using databases

If you using multiple databases, for example: PostgreSQL, Clickhouse.

Schema dump to db/clickhouse_schema.rb file:

$ rake clickhouse:schema:dump

Schema load from db/clickhouse_schema.rb file:

$ rake clickhouse:schema:load

For export schema to PostgreSQL, you need use:

$ rake clickhouse:schema:dump -- --simple

Schema will be dump to db/clickhouse_schema_simple.rb. If default file exists, it will be auto update after migration.

Structure dump to db/clickhouse_structure.sql file:

$ rake clickhouse:structure:dump

Structure load from db/clickhouse_structure.sql file:

$ rake clickhouse:structure:load

Dump / Load for only Clickhouse database using

$ rake db:schema:dump  
$ rake db:schema:load  
$ rake db:structure:dump  
$ rake db:structure:load  

Insert and select data

Action.where(url: 'http://example.com', date: Date.current).where.not(name: nil).order(created_at: :desc).limit(10)
# Clickhouse Action Load (10.3ms)  SELECT  actions.* FROM actions WHERE actions.date = '2017-11-29' AND actions.url = 'http://example.com' AND (actions.name IS NOT NULL)  ORDER BY actions.created_at DESC LIMIT 10
#=> #<ActiveRecord::Relation [#<Action *** >]>

Action.create(url: 'http://example.com', date: Date.yesterday)
# Clickhouse Action Load (10.8ms)  INSERT INTO actions (url, date) VALUES ('http://example.com', '2017-11-28')
#=> true
 
ActionView.maximum(:date)
# Clickhouse (10.3ms)  SELECT maxMerge(actions.date) FROM actions
#=> 'Wed, 29 Nov 2017'

Migration Data Types

Integer types are unsigned by default. Specify signed values with :unsigned => false. The default integer is UInt32

Type (bit size)	Range	:limit (byte size)
Int8	-128 to 127	1
Int16	-32768 to 32767	2
Int32	-2147483648 to 2,147,483,647	3,4
Int64	-9223372036854775808 to 9223372036854775807]	5,6,7,8
Int128	...	9 - 15
Int256	...	16+
UInt8	0 to 255	1
UInt16	0 to 65,535	2
UInt32	0 to 4,294,967,295	3,4
UInt64	0 to 18446744073709551615	5,6,7,8
UInt256	0 to ...	8+

Example:

class CreateDataItems < ActiveRecord::Migration
  def change
    create_table "data_items", id: false, options: "VersionedCollapsingMergeTree(sign, version) PARTITION BY toYYYYMM(day) ORDER BY category", force: :cascade do |t|
      t.date "day", null: false
      t.string "category", null: false
      t.integer "value_in", null: false
      t.integer "sign", limit: 1, unsigned: false, default: -> { "CAST(1, 'Int8')" }, null: false
      t.integer "version", limit: 8, default: -> { "CAST(toUnixTimestamp(now()), 'UInt64')" }, null: false
    end
  end
end
      

Using replica and cluster params in connection parameters

default: &default
  ***
  cluster_name: 'cluster_name'
  replica_name: '{replica}'

ON CLUSTER cluster_name will be attach to all queries create / drop.

Engines MergeTree and all support replication engines will be replaced to Replicated***('/clickhouse/tables/cluster_name/database.table', '{replica}')

Donations

Donations to this project are going directly to PNixx, the original author of this project:

• BTC address: 1H3rhpf7WEF5JmMZ3PVFMQc7Hm29THgUfN
• ETH address: 0x6F094365A70fe7836A633d2eE80A1FA9758234d5
• XMR address: 42gP71qLB5M43RuDnrQ3vSJFFxis9Kw9VMURhpx9NLQRRwNvaZRjm2TFojAMC8Fk1BQhZNKyWhoyJSn5Ak9kppgZPjE17Zh

Development

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/pnixx/clickhouse-activerecord. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.