However the copy procces of  Magento shop has following main steps

• duplication of database schema
• duplication of core sources
• duplication of downloader sources

Database

First, let me say say, that it is good idea to not install two Magento instances to the same database. Magento in  version 1.1.8 s has 198 database tables. Most of them are of type  InnoDB and they are  related with each other by checked foreign key constraints. That is background information.

So new database for every  Magento instance save you from having headaches  and this not only because having just two magento installation i one DB leads too approx. 400 tables in one database but more to avoid possible problems or side effects with constraints and Co. (e.g. ) .  .

The easiest way to export the database is to use phpMyAdmin. Go to export dialog of original database, select “zipped” option, select tabbles, let other options on their defaults (See screen 1) and get zipped download. Switch to new database and  upload the downloaded  there in the import dialog.

Sound as a piece of cake, but sometimes the import of the SQL files will not work. I have already seen many different exceptions bu trying. Beginning with “SQL Syntax..” and ending with “constraint violation…”.  In my opinion the purpose of problems is size of some tables and therefore of whole backup. There are few MyISAM tables that are full with (useless) log data. And the amount of this data makes problems to the import routine. Don’t export them first at time! they don’t have any constraint to other tables so you can import them on second or third turn. Alternative  you can export only the DDL-Statement of this table not the data itself.

Here are tables you can  omit in first step:

• log_url
• log_url_info
• log_visitor
• log_visitor_info

Don’t forget to change configured URL of origin shop to the  URLs of new shop in the table core_config_data. You can also use Search-Tool of phpMyAdmin and identify every record where old URL is used – but outside of core_config_data table  they are not so important and could be changed later in the Shop interface.

Core Sources

That is most easiest part. Just copy the source of magento to the new location, but don’t copy the following:

• downloader dir
• any content of dirs inside of var but .htacces file.
• media/tmp dir

If you use another DB for new Magento installation don’t forget to change DB setting in app/etc/local.xml file. Var directory hold any temporary content like sessions, caches and error-logs. Downloader is used by Magento connect module, before copy must do some preparations.

Magento Downloader

Warning! do not copy unchanged downloader to new location on the same server it may break your origin magento installation!

Now I got your attention The problem is that downloder stores serverpath in many many configuration files. And if you don’t change the serverpath  and  starts updates on  new shop copy, you will update the origin shop and not the new copy of it!

The server path of origin magento shop is stored in many many files in the downloader directory, you can’t change all of them manually. But you can do it automatically. If you have SSH access to your web-space  following command will help you:

Update: The described way to handle downloader sometimes causes problems by doing upgrade. Especially pear.ini shold be treatet carefully. Check also a workaround proposed by Enno Julian.

//shows all files with OLD_PATH element

find  . -type f -exec grep -q "OLD_PATH" '{}' \; -print

//Replaces OLD_PATH string in all occurrences in every file to NEW_PATH

find . -type f -print | xargs sed -i -e ’s/OLD_PATH/NEW_PATH/g’

If you have only ftp access, then you can use [Alt+F7]-search in Total Commander. Then open each file with Notepad++ and then use “Search and Replace” functionality of Notepad++ on each file. Whole replacement willtake you max. 5 minutes.

After replacing old path you can upload downloader to the new instance of Magento.

Now everything including “Magento Connect” should work properly and independent form each othen on thow instances. The last thing my be useful   is to clear all caches in admin back-end of new instance. Good luck!

Open Question

This article describes how to double the Magento instance once. The next question which i didn’t answered for me yet is how to make permanent  mirroring of data from production environment to the test installation. Maybe someone has cool ideas?

Disclaimer

Please consider that I can’t guarantee that everything described here will work in your environment as it worked for me. Please use this tutorial as incitement and adopt my methods to your own situation. Be sure that you don’t peril origin Magento installation or other data. Do regular backup befor you begin!

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The Problem

Every time on  the installation of Magento i saw following  exception.

Error in file: ".... app/code/core/Mage/Core/sql/core_setup/mysql4-install-0.8.0.php" - SQLSTATE[HY000]: General error: 1005 Can't create table './db203484_1/#sql-1dd4_17baf.frm' (errno: 121)
Trace:
#0 .../app/code/core/Mage/Core/Model/Resource/Setup.php(286): Mage::exception('Mage_Core', 'Error in file: ...')
#1 ...app/code/core/Mage/Core/Model/Resource/Setup.php(166): Mage_Core_Model_Resource_Setup->_modifyResourceDb('install', '', '0.8.11')
#2 .../app/code/core/Mage/Core/Model/Resource/Setup.php(154): Mage_Core_Model_Resource_Setup->_installResourceDb('0.8.11')
#3 .../app/code/core/Mage/Core/Model/Resource/Setup.php(120): Mage_Core_Model_Resource_Setup->applyUpdates()
#4 .../app/code/core/Mage/Core/Model/Config.php(215): Mage_Core_Model_Resource_Setup::applyAllUpdates()
#5 .../app/code/core/Mage/Core/Model/App.php(236): Mage_Core_Model_Config->init(Array)
#6 .../app/Mage.php(424): Mage_Core_Model_App->init('', 'store', Array)
#7 .../app/Mage.php(443): Mage::app('', 'store', Array)
#8 .../index.php(52): Mage::run()
#9 {main}

I tried installation with version 1.1.3, 1.1.4, 1.1.6 and 1.1.8 nothing helped…

You can find many threads on Magentocommere Forum to this issue. Some hints may help you once but do not solve the problem. I guess I don’t have solved problem globally. But I found the cause of the problem so everybody can solve it on his own way.

Cause of the exception

During the installation routine  many DB-Tables should be created in your Database. We talk here about MySQL Database.  So Magento begins with SQL-Statement that are holded in the mysql4-install-0.8.0.php. This file is also pintet in the Exception message as the causes of the problem.

I analysed the Statement and this came out..

Before any CREATE-Statement – Magento executes this:

SET SQL_MODE=''
SET @OLD_FOREIGN_KEY_CHECKS=@@
FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO'

Then, after all tables and indexes  defined in  mysql4-install-0.8.0.php are created, magento executes following Statement.:

SET SQL_MODE=IFNULL(@OLD_SQL_MODE,'')
SET FOREIGN_KEY_CHECKS=IFNULL(@OLD_FOREIGN_KEY_CHECKS,0)

An the last row causes #1231 – Variable ‘foreign_key_checks’ can’t be set to the value of ‘0’ Exception which is finely identified by me as  the cause of such installation problems!

Solution

I did’n spend much time to find out why the Varibale SET FOREIGN_KEY_CHECKS can’t be set to ’0′, because it looks like MySQL bug.

However, it’s maybe not the finest solution but it helps. If you can drop the whole the database and create new one, then the installation works. It seems to set all the before settings back and installtion works fine on “vergin-Databases”.

If you  feel experienced in MYSQL and has an Idea how to overcome this problem without creating new Databases please make your comment !

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There are only few bugs remained in that late version, even if I was still able to find some of them. Furthermore Magento-people have really speed their System up, which was enormously important to my eyes. So now it seems that Magento becomes really competitive E Commerce Platform and that is just great! If the development goes so further on. None of the competing Systems will survive.

However one need much time to get familiar with Magento. That platform brings very much functionality and configuration options, so configuring Magento can become a new Profession! Unfortunately Configuration Options are just sparse documented at that point, so there is bunch of try and error till one can get his first Online-Shop of dreams.

On the other side Magento has growing online Community, which is effect more worth as full documentation.

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It is done professional! Yes, in my opinion that describes all advantages of that shop short. Cause in comparison to others shop systems it offers very much functionality and flexibility out of the box, combined with good looking default template. Just visit the demo-shop of Magento to see it self. I will not describe every detail of Magento here, cause it was done many times before, like that article, which describes (in German) why Magento is flexible, self-contained, individual, and is prepared for the future. But the best impression you can make by trying it out. I tried it for you and i can point some disadvantages to.

The greatest disadvantage of that system is that its powered by Zend Framework. Wait! You are Zend Framework evangelist? Let me explain. I don’t say that Zend Framework is bad, no i say – it’s slow ! Of cause it may be that Magento is so bad written on that brilliant framework making it, so slow, i don’t know, but it is really, really slow on normal PHP without Zend engine. And it’s don’t comes out with standard 8Mb configuration of your PHP engine, it needs at least 20Mb, otherwise it not works.

And of cause you need some not ever usual extensions of your PHP (which is PHP 5.2.0 or newer):

• PDO/MySQL
• MySQLi
• mcrypt
• mhash
• simplexml
• DOM

I called my host provider before a had all required addons. But i was supported by good installation routine in this exercise.

Further my shop installation was not such intuitive as it can be in the admin area, but it’s OK, cause there are really many configuration possibilities that have to be placed somewhere. I think it will mature in the future and is not so relevant at all ,cause admins will learn how to configure Magento, but customer will/must not learn it. And precisely customers will like your Magento usability, i think.

Last but not least my version (0.6.13…) of Magneto was pretty buggy. After doing some configuration steps in admin area the store produces errors (Zend Framework pointed me to SQL Errors) and was no more functional anymore . That are of cause teething problems, that are possibly already fixed in the new Version: “… Fixed few database foreign keys problems …“.

Finally i would say, that Magento is best online shop system that i know at the moment, i will stay watching Magento development and will try out newer matured versions. But at the moment Magento is not really ready for productive run, especially the slowness of the systen is greatest disadvantage of Magento for me.

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