Class: Coupler::ImportBuffer

Inherits:
Object
  • Object
show all
Defined in:
lib/coupler/import_buffer.rb

Overview

This class is used during resource transformation. Its purpose is for mass inserts into the local database for speed.

Constant Summary collapse

MAX_QUERY_SIZE = 
1_048_576

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(columns, dataset, &progress) ⇒ ImportBuffer

Returns a new instance of ImportBuffer.



9
10
11
12
13
14
15
 
# File 'lib/coupler/import_buffer.rb', line 9

def initialize(columns, dataset, &progress)
  @columns = columns
  @dataset = dataset
  @mutex = Mutex.new
  @progress = progress
  @pending = 0
end

Instance Attribute Details

#dataset=(value) ⇒ Object (writeonly)

Sets the attribute dataset

Parameters:

  • value —

    the value to set the attribute dataset to.



7
8
9
 
# File 'lib/coupler/import_buffer.rb', line 7

def dataset=(value)
  @dataset = value
end

Instance Method Details

#add(row) ⇒ Object 



17
18
19
20
21
22
23
24
25
26
27
28
 
# File 'lib/coupler/import_buffer.rb', line 17

def add(row)
  fragment = " " + @dataset.literal(row.is_a?(Hash) ? row.values_at(*@columns) : row) + ","
  @mutex.synchronize do
    init_query  if @query.nil?
    if (@query.length + fragment.length) > MAX_QUERY_SIZE
      flush(false)
      init_query
    end
    @query << fragment
    @pending += 1
  end
end

#flush(lock = true) ⇒ Object 



30
31
32
33
34
35
36
37
38
39
40
41
42
 
# File 'lib/coupler/import_buffer.rb', line 30

def flush(lock = true)
  begin
    @mutex.lock   if lock
    if @query
      @dataset.db.run(@query.chomp(","))
      @progress.call(@pending) if @progress
      @pending = 0
      @query = nil
    end
  ensure
    @mutex.unlock if lock
  end
end