If you have SSH access to your Linux (or Unix) server you can easy re-index Magento database from Linux command shell.

You can use such re-index method to decrease load on your server. The PHP shell commands will be executed directly, without Apache overloading.

Here is an instruction on how to use default Magento indexer via SSH console:

1 - Go to "shell" folder in your Magento installation:

cd shell

2 - Execute the re-index process using this command:

php -f indexer.php reindexall

It is possible to get full list of Magento indexer commands using this command:

php -f indexer.php help

To get a list of all available indexes, execute this command:

php -f indexer.php info

By default there are 8 indexes in Magento:

catalog_product_attribute     Product Attributes
catalog_product_price         Product Prices
catalog_url                   Catalog Url Rewrites
catalog_product_flat          Product Flat Data
catalog_category_flat         Category Flat Data
catalog_category_product      Category Products
catalogsearch_fulltext        Catalog Search Index
cataloginventory_stock        Stock status