Class: Groupdate::Adapters::RedshiftAdapter

Inherits:
BaseAdapter
  • Object
show all
Defined in:
lib/groupdate/adapters/redshift_adapter.rb

Instance Attribute Summary

Attributes inherited from BaseAdapter

#column, #day_start, #n_seconds, #period, #week_start

Instance Method Summary collapse

Methods inherited from BaseAdapter

#generate, #initialize

Constructor Details

This class inherits a constructor from Groupdate::Adapters::BaseAdapter

Instance Method Details

#group_clause ⇒ Object 



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# File 'lib/groupdate/adapters/redshift_adapter.rb', line 4

def group_clause
  time_zone = @time_zone.tzinfo.name
  day_start_column = "CONVERT_TIMEZONE(?, #{column}::timestamp) - INTERVAL ?"
  day_start_interval = "#{day_start} second"

  query =
    case period
    when :minute_of_hour
      ["EXTRACT(MINUTE from #{day_start_column})::integer", time_zone, day_start_interval]
    when :hour_of_day
      ["EXTRACT(HOUR from #{day_start_column})::integer", time_zone, day_start_interval]
    when :day_of_week
      ["EXTRACT(DOW from #{day_start_column})::integer", time_zone, day_start_interval]
    when :day_of_month
      ["EXTRACT(DAY from #{day_start_column})::integer", time_zone, day_start_interval]
    when :day_of_year
      ["EXTRACT(DOY from #{day_start_column})::integer", time_zone, day_start_interval]
    when :month_of_year
      ["EXTRACT(MONTH from #{day_start_column})::integer", time_zone, day_start_interval]
    when :week # start on Sunday, not Redshift default Monday
      # Redshift does not return timezone information; it
      # always says it is in UTC time, so we must convert
      # back to UTC to play properly with the rest of Groupdate.
      week_start_interval = "#{week_start} day"
      ["CONVERT_TIMEZONE(?, 'Etc/UTC', DATE_TRUNC('week', #{day_start_column} - INTERVAL ?) + INTERVAL ? + INTERVAL ?)::timestamp", time_zone, time_zone, day_start_interval, week_start_interval, week_start_interval, day_start_interval]
    when :custom
      raise Groupdate::Error, "Not implemented yet"
    else
      ["CONVERT_TIMEZONE(?, 'Etc/UTC', DATE_TRUNC(?, #{day_start_column}) + INTERVAL ?)::timestamp", time_zone, period, time_zone, day_start_interval, day_start_interval]
    end

  @relation.send(:sanitize_sql_array, query)
end