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Ditto

Ditto is a tool that lets you easily replicate your existing MySQL data into MemSQL.

Dependencies

Ditto requires the following software:

  • MySQL <= 5.5 (5.6 is not supported)
  • Python 2.7
  • MemSQL
  • MySQL-Python
  • mysqldump

Installation

The replication scripts come bundled with a modified version of the python-mysql-replication library that must be installed before we can replicate.

Enter the python-mysql-replication directory:

$ python setup.py install

MySQL server settings

In your MySQL server configuration file (usually at /etc/mysql/my.cnf) you need to enable replication. Make sure the following options are set as below:

[mysqld]
server-id		 = 1
log_bin			 = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size  = 100M
binlog-format    = row

Usage

The replication script is replicate.py. To run the script, enter the scripts directory:

$ python replicate.py [database]

This script will recreate the specified database in MemSQL. By default, it first runs mysqldump on the database and flushes the binlog. Then it waits for queries on the current binlog that pertain to the specified database and runs them on MemSQL. To stop the program, send it an interrupt. There are a number of settings you can tweak at the command line:

$ python replicate.py --help


usage: replicate.py [-h] [--host HOST] [--user USER] [--password PASSWORD]
                    [--mysql-port MYSQL_PORT] [--memsql-port MEMSQL_PORT]
                    [--no-dump] [--no-flush]
                    database

Replicate a MySQL database to MemSQL

positional arguments:
database              Database to use

optional arguments:
-h, --help            show this help message and exit
--host HOST           Host where the database server is located
--user USER           Username to log in as
--password PASSWORD   Password to use
--mysql-port MYSQL_PORT
                        MySQL port to use
--memsql-port MEMSQL_PORT
                        MemSQL port to use
--no-dump             Don't run mysqldump before reading (expects schema to
                        already be set up)
--no-flush            Don't flush the binlog before reading (may duplicate
                        existing data)

The scripts directory also contains test_replication.py. This script will replicate a specific database from MySQL to MemSQL using mysqldump and the current binlog and then verify that the content of all tables in the MySQL database match those in the newly created MemSQL database. It can be run in the same manner as replicate.py, though it is not intended for replication, as it doesn't wait for new queries on the current binlog. To print out all queries in the current binlog, run the dump_queries.py script.

Licence

Copyright 2013 MemSQL, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

The memsql_database.py file is a modified version of the original file that is part of Facebook's Tornado project.