gitlabhq/gitlab-ci

MySQL to PostgreSQL Converter
=============================

Lanyrd's MySQL to PostgreSQL conversion script. Use with care.

This script was designed for our specific database and column requirements -
notably, it doubles the lengths of VARCHARs due to a unicode size problem we
had, places indexes on all foreign keys, and presumes you're using Django
for column typing purposes.

GitLab-specific changes
-----------------------

The `gitlab` branch of this fork contains the following changes made for
GitLab.

- Guard against replacing '0000-00-00 00:00:00' inside SQL text fields.
- Replace all MySQL zero-byte string literals `\0`. This is safe as of GitLab
  6.8 because the GitLab database schema contains no binary columns.
- Never set 'NOT NULL' constraints on datetimes.
- Drop sequences before creating them.
- Preserve default values of boolean (originally `tinyint(1)`) columns.
- Import all indexes.
- Import index names.
- Drop tables before creating.
- Drop indexes before creating.

How to use
----------

First, dump your MySQL database in PostgreSQL-compatible format

    mysqldump --compatible=postgresql --default-character-set=utf8 \
    -r databasename.mysql -u root gitlabhq_production -p

Then, convert it using the dbconverter.py script.

    python db_converter.py databasename.mysql - drop_indexes.sql | gzip -c > databasename.unfinished.psql.gz

It'll print progress to the terminal

Now we have a DB dump that can be imported but the dump will be slow due
to existing indexes.

    ./splice_drop_indexes databasename.unfinished.psql.gz drop_indexes.sql > databasename.psql

Next, load your new dump into a fresh PostgreSQL database using: 

`psql -f databasename.psql -d gitlabhq_production`

More information
----------------

You can learn more about the move which this powered at http://lanyrd.com/blog/2012/lanyrds-big-move/ and some technical details of it at http://www.aeracode.org/2012/11/13/one-change-not-enough/.