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Versions: 11
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Contents
# Copyright (c) 2011 - 2013, SoundCloud Ltd., Rany Keddo, Tobias Bielohlawek, Tobias
# Schmidt
require 'lhm/command'
require 'lhm/migration'
require 'lhm/sql_retry'
module Lhm
# Switches origin with destination table using an atomic rename.
#
# It should only be used if the MySQL server version is not affected by the
# bin log affecting bug #39675. This can be verified using
# Lhm::SqlHelper.supports_atomic_switch?.
class AtomicSwitcher
include Command
attr_reader :connection
LOG_PREFIX = "AtomicSwitcher"
def initialize(migration, connection = nil)
@migration = migration
@connection = connection
@origin = migration.origin
@destination = migration.destination
end
def atomic_switch
"RENAME TABLE `#{ @origin.name }` TO `#{ @migration.archive_name }`, " \
"`#{ @destination.name }` TO `#{ @origin.name }`"
end
def validate
unless @connection.data_source_exists?(@origin.name) &&
@connection.data_source_exists?(@destination.name)
error "`#{ @origin.name }` AND `#{ @destination.name }` MUST EXIST"
end
end
private
def execute
@connection.execute(atomic_switch, should_retry: true, log_prefix: LOG_PREFIX)
end
end
end
Version data entries
11 entries across 11 versions & 1 rubygems