class RedshiftConnector::Importer::RebuildRename
Public Class Methods
get_unique_sequence()
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# File lib/redshift_connector/importer/rebuild_rename.rb, line 42 def self.get_unique_sequence @dao_seq_lock.synchronize { @dao_seq += 1 } end
make_temporary_dao(orig)
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Duplicates DAO (ActiveRecord class) and names it. Newer activerecord-import requires a class name (not a table name), we must prepare some name for temporary DAO class.
# File lib/redshift_connector/importer/rebuild_rename.rb, line 32 def self.make_temporary_dao(orig) tmp = orig.dup const_set("TemporaryDAO_#{get_unique_sequence}", tmp) tmp.name # fix class name tmp end
new(dao:, columns:, logger: RedshiftConnector.logger)
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# File lib/redshift_connector/importer/rebuild_rename.rb, line 7 def initialize(dao:, columns:, logger: RedshiftConnector.logger) @dao = dao @columns = columns @logger = logger end
Public Instance Methods
exec_update(query)
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# File lib/redshift_connector/importer/rebuild_rename.rb, line 46 def exec_update(query) @logger.info query @dao.connection.execute(query) end
execute(bundle)
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# File lib/redshift_connector/importer/rebuild_rename.rb, line 13 def execute(bundle) dest_table = @dao.table_name tmp_table = "#{dest_table}_new" old_table = "#{dest_table}_old" tmp_dao = self.class.make_temporary_dao(@dao) tmp_dao.table_name = tmp_table exec_update "drop table if exists #{tmp_table}" exec_update "create table #{tmp_table} like #{dest_table}" import(tmp_dao, bundle) exec_update "drop table if exists #{old_table}" # Atomic table exchange exec_update "rename table #{dest_table} to #{old_table}, #{tmp_table} to #{dest_table}" end
import(dao, bundle)
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# File lib/redshift_connector/importer/rebuild_rename.rb, line 51 def import(dao, bundle) @logger.info "IMPORT #{bundle.url}* -> #{dao.table_name} (#{@columns.join(', ')})" bundle.each_batch do |rows| dao.import(@columns, rows) end end