Class: Sq::Dbsync::BatchLoadAction

Inherits:
LoadAction show all
Defined in:
lib/sq/dbsync/batch_load_action.rb

Overview

Load action to reload an entire table in full. The table will be loaded in parallel to the existing one, then atomically swapped in on completion.

Constant Summary collapse

MAX_LAG = 
60 * 5

Constants inherited from LoadAction

LoadAction::EPOCH

Instance Method Summary collapse

Methods inherited from LoadAction

#call, #do_prepare, #initialize, stages, #tag

Constructor Details

This class inherits a constructor from Sq::Dbsync::LoadAction

Instance Method Details

#extract_data ⇒ Object 



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# File 'lib/sq/dbsync/batch_load_action.rb', line 22

def extract_data
  @start_time  = now.call
  @file, @last_row_at = measure(:extract) { extract_to_file(nil) }
  self
end

#load_data ⇒ Object 



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# File 'lib/sq/dbsync/batch_load_action.rb', line 28

def load_data
  measure(:load) do
    TempfileFactory.split(@file, 1_000_000, logger) do |path|
      db.load_from_file(
        plan.prefixed_table_name,
        plan.columns,
        path
      )
    end
    @file.close!
  end
  self
end

#operation ⇒ Object 



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# File 'lib/sq/dbsync/batch_load_action.rb', line 9

def operation; 'batch'; end

#post_load ⇒ Object 



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# File 'lib/sq/dbsync/batch_load_action.rb', line 42

def post_load
  while @start_time <= now.call - MAX_LAG
    @start_time = now.call
    catchup
  end

  switch_tables
  self
end

#prepare ⇒ Object 



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# File 'lib/sq/dbsync/batch_load_action.rb', line 11

def prepare
  return false if plan.batch_load == false

  if super
    if target.table_exists?(plan.prefixed_table_name)
      target.drop_table(plan.prefixed_table_name)
    end
    true
  end
end