NMIG is an app, intended to make a process of migration from MySQL to PostgreSQL as easy and smooth as possible.
- Precise migration of the database structure - NMIG converts MySQL data types to corresponding PostgreSQL data types, creates constraints, indexes, primary and foreign keys exactly as they were before migration.
- Ability to migrate big databases - in order to eliminate "process out of memory" issues NMIG will split each table's data into several chunks.
Each group of chunks will be loaded via separate worker process. - Speed of data transfer - in order to migrate data fast NMIG uses PostgreSQL COPY protocol.
- Ability to recover migration process if disaster took place (without restarting from the beginning).
- Ease of monitoring - NMIG will provide detailed output about every step, it takes during the execution.
- Ease of configuration - all the parameters required for migration should be put in one single JSON document.
- Node.js 5 or greater
1. Create a new database.
Sample: CREATE DATABASE my_postgresql_database;
2. Download NMIG package and put it on the machine running your PostgreSQL (not mandatory, but preferably).
Sample: /path/to/nmig
3. Edit configuration file located at /path/to/nmig/config.json with correct details.
- config.json contains brief description of each configuration parameter
- Make sure, that username, you use in your PostgreSQL connection details, defined as superuser (usually "postgres")
More info: http://www.postgresql.org/docs/current/static/app-createuser.html
4. Go to nmig directory, install dependencies, and run the app
Sample:
$ cd /path/to/nmig
$ npm install
$ node nmig.js
5. If a disaster took place during migration (for what ever reason) - simply restart the process
$ node nmig.js
NMIG will restart from the point it was stopped at.
6. At the end of migration check log files, if necessary.
Log files will be located under "logs_directory" folder in the root of the package.
Note: "logs_directory" will be created during script execution.
7. In case of any remarks, misunderstandings or errors during migration,
please feel free to email me
[email protected]
Current version is 2.3.0
(major version . improvements . bug fixes)
Tested using MySQL Community Server (5.6.21) and PostgreSQL (9.3).
The entire process of migration 59.6 MB database (52 tables, 570754 rows),
which includes data types mapping, creation of tables, constraints, indexes,
PKs, FKs, migration of data, garbage-collection (VACUUM) and analyzing the newly created
PostgreSQL database took 1 minute 18 seconds.
Note: it is highly recommended to VACUUM newly created database!
Just keep in mind, that VACUUM is a very time-consuming procedure.
So if you are short in time - disable VACUUM via config.json ("no_vacuum" parameter).
Such step will save you ~25% of migration time.
The migration process described above without VACUUM took 58 seconds only.
Errors/Exceptions are not passed silently.
Any error will be immediately written into the error log file.
- Empty strings in char/varchar columns may be interpreted as NULL.
NMIG is available under "GNU GENERAL PUBLIC LICENSE" (v. 3)
http://www.gnu.org/licenses/gpl.txt.