If you store large objects in the database (such as JSON), for example, data for big reports, then this can take up a lot of space. To reduce the size of data, you can compress and store in binary form.

PostgreSQL has a bytea field type for storing such data. You can add bytea column in Rails using migration


add_column :reports, :data, :binary

For binary field operations, you can use the Rails Attributes API and add a new BinaryHash data type


# app/types/binary_hash.rb



class BinaryHash < ActiveRecord::Type::Binary

  def serialize(value)

    super value_to_binary(value.to_json)

  end



  def deserialize(value)

    super case value

          when NilClass

            {}

          when ActiveModel::Type::Binary::Data

            value_to_hash(value.to_s)

          else

            value_to_hash(PG::Connection.unescape_bytea(value))

          end

  end



  private



  def value_to_hash(value)

    JSON.parse(

      ActiveSupport::Gzip.decompress(value),

      symbolize_names: true

    ) || {}

  end



  def value_to_binary(value)

    ActiveSupport::Gzip.compress(value)

  end

end

Register new type in initializers


# config/initializers/types.rb



ActiveRecord::Type.register(:binary_hash, BinaryHash)

And add to binary type attribute in model


# app/models/snapshot.rb



class Reports < ApplicationRecord

  attribute :data, :binary_hash

end

Tests show that data size is reduced by almost 3 times


Run time with 100000 width JSON

                           user     system      total        real

Compress JSON          0.008671   0.001535   0.010206 (  0.010885)

Decompress JSON        0.001357   0.000095   0.001452 (  0.001509)



json size       95450 bytes

binary size   33868 bytes

~ 2.82 times compression
#ruby #rails #postgresql
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