Magento has a very sophisticated architecture that stores lots of merchant data (including catalog data, prices, users, stores, and so on) in many database tables. To optimize web store performance, Magento accumulates data into special tables using indexers.
For example, suppose you change the price of an item from $4.99 to $3.99. Magento must reindex the price change to display it on your web store.
Without indexing, Magento would have to calculate the price of every product on the fly – taking into account shopping cart price rules, bundle pricing, discounts, tier pricing, and so on. Loading the price for a product would take a long time, possibly resulting in cart abandonment.
Magento Reindex can be done from Magento Admin panel as well as from the Shell, the latter one being the most successful all time. Some times clients may request us to re-index their products. So lets see how to do this.
It is possible to re-index some attributes.