Class: RubySnowflake::StreamingResult

Inherits:
Result
  • Object
show all
Defined in:
lib/ruby_snowflake/streaming_result.rb

Instance Attribute Summary

Attributes inherited from Result

#data

Instance Method Summary collapse

Methods inherited from Result

#[]=, #columns, #first, #get_all_rows

Constructor Details

#initialize(partition_count, row_type_data, retreive_proc) ⇒ StreamingResult

Returns a new instance of StreamingResult.



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# File 'lib/ruby_snowflake/streaming_result.rb', line 9

def initialize(partition_count, row_type_data, retreive_proc)
  super(partition_count, row_type_data)
  @retreive_proc = retreive_proc
end

Instance Method Details

#each ⇒ Object 



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# File 'lib/ruby_snowflake/streaming_result.rb', line 14

def each
  return to_enum(:each) unless block_given?

  thread_pool = Concurrent::FixedThreadPool.new 1

  data.each_with_index do |_partition, index|
    next_index = [index+1, data.size-1].min
    if data[next_index].nil? # prefetch
      data[next_index] = Concurrent::Future.execute(executor: thread_pool) do
        @retreive_proc.call(next_index)
      end
    end

    if data[index].is_a? Concurrent::Future
      data[index] = data[index].value # wait for it to finish
    end

    data[index].each do |row|
      yield wrap_row(row)
    end

    # After iterating over the current partition, clear the data to release memory
    data[index].clear

    # Reassign to a symbol so:
    # - When looking at the list of partitions in `data` it is easier to detect
    # - Will raise an exception if `data.each` is attempted to be called again
    # - It won't trigger prefetch detection as `next_index`
    data[index] = :finished
  end
end

#last ⇒ Object 



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# File 'lib/ruby_snowflake/streaming_result.rb', line 51

def last
  not_implemented
end

#size ⇒ Object 



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# File 'lib/ruby_snowflake/streaming_result.rb', line 47

def size
  not_implemented
end