class BigShift::RedshiftUnloader
Public Class Methods
new(redshift_connection, aws_credentials, options={})
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# File lib/bigshift/redshift_unloader.rb, line 3 def initialize(redshift_connection, aws_credentials, options={}) @redshift_connection = redshift_connection @aws_credentials = aws_credentials @logger = options[:logger] || NullLogger::INSTANCE end
Public Instance Methods
unload_to(schema_name, table_name, s3_uri, options={})
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# File lib/bigshift/redshift_unloader.rb, line 9 def unload_to(schema_name, table_name, s3_uri, options={}) table_schema = RedshiftTableSchema.new(schema_name, table_name, @redshift_connection) credentials_string = "aws_access_key_id=#{@aws_credentials.access_key_id};aws_secret_access_key=#{@aws_credentials.secret_access_key}" select_sql = 'SELECT ' select_sql << table_schema.columns.map(&:to_sql).join(', ') select_sql << %Q< FROM "#{schema_name}"."#{table_name}"> select_sql.gsub!('\'') { |s| '\\\'' } unload_sql = %Q<UNLOAD ('#{select_sql}')> unload_sql << %Q< TO '#{s3_uri}'> unload_sql << %Q< CREDENTIALS '#{credentials_string}'> unload_sql << %q< MANIFEST> unload_sql << %q< DELIMITER '\t'> unload_sql << %q< GZIP> if options[:compression] || options[:compression].nil? unload_sql << %q< ALLOWOVERWRITE> if options[:allow_overwrite] unload_sql << %q< MAXFILESIZE 3.9 GB> @logger.info(sprintf('Unloading Redshift table %s to %s', table_name, s3_uri)) @redshift_connection.exec(unload_sql) @logger.info(sprintf('Unload of %s complete', table_name)) end