How to upgrade big Magento site to v1.4 or higher version

One of our clients has a big Magento site (the database size is as big as 600MB) need to be upgraded from 1.3.x to 1.4.x. After several attempts, we were not able to upgrade it smoothly, and it's caused by the the huge database.

Since when the system execute the upgrade to higher version of Magento, the upgrade program will examine your current code, css and database.

From 1.3.x to 1.4.x, the system need to merge current data to a new empty data which is using for the new version of Magento. We can not simply consider this process as an importing process, some table structure need to be upgrade too.

This step will depends on our data size. the smaller data size we have the less time. currently, the data size of this live site is almout 600M. That's why we can not upgrade the site and the system got frozen, and no response at all.

So now there are two solutions:

Option 1. we can upgrade Magento with connector, this function will only upgrade Magento core files, by using following command in connector to process the upgrade:

magento-core/Mage_All_Latest

we tried both ways, the connector was successful, but only upgrade core files. And the version code will still shown as v1.3.x; which means, it's just a part upgrading.

Option 2. We would manually tailor the 600mb DB into around 10MB, mainly just deleting the product data info.

So we would make the upgrade successful and get a pilot 1.4.x version, by this way, we can research the difference and changes of DB;

And then, we can write a pure php script (or SQL queries), to make the DB conversion on an independent environment, not under Magento.

Once we make it, we will just importing rest part of product into the the upgraded DB.