Class: NoSE::Loader::SqlLoader

Inherits:
LoaderBase show all
Defined in:
lib/nose/loader/sql.rb

Overview

Load data from a MySQL database into a backend

Instance Method Summary collapse

Methods inherited from LoaderBase

#model, #workload

Constructor Details

#initialize(workload = nil, backend = nil) ⇒ SqlLoader

Returns a new instance of SqlLoader.



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# File 'lib/nose/loader/sql.rb', line 9

def initialize(workload = nil, backend = nil)
  @logger = Logging.logger['nose::loader::sqlloader']

  @workload = workload
  @backend = backend
end

Instance Method Details

#load(indexes, config, show_progress = false, limit = nil, skip_existing = true) ⇒ Object

Load a generated set of indexes with data from MySQL



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# File 'lib/nose/loader/sql.rb', line 17

def load(indexes, config, show_progress = false, limit = nil,
         skip_existing = true)
  indexes.map!(&:to_id_graph).uniq! if @backend.by_id_graph

  # XXX Assuming backend is thread-safe
  Parallel.each(indexes, in_threads: 2) do |index|
    client = new_client config

    # Skip this index if it's not empty
    if skip_existing && !@backend.index_empty?(index)
      @logger.info "Skipping index #{index.inspect}" if show_progress
      next
    end
    @logger.info index.inspect if show_progress

    query = index_sql client, index, limit

    result_chunk = []
    query.each do |result|
      result = Hash[result.map { |k, v| [k.to_s, v] }]
      result_chunk.push result
      if result_chunk.length >= 100
        @backend.index_insert_chunk index, result_chunk
        result_chunk = []
      end
    end
    @backend.index_insert_chunk index, result_chunk \
      unless result_chunk.empty?
  end
end