The new feature gives control to Web publishers over the frequency with which Google refreshes its index of the site's content, something that until now had been automatically scheduled by Google's system based on internal algorithms.

On-Demand Indexing will go live on Thursday. In their Site Search control panel, Web publishers will see a new button labeled "index now" that, when clicked on, will activate this new feature.

"On demand indexing is like supercharging the Site Search product so that our customers -- the Web site owners -- can come to Google as their Web sites are changing and say 'I just added 100 or 1,000 pages -- please index them now,'" said Nitin Mangtani, Google's lead product manager for enterprise search.

On-Demand Indexing should come in handy when a site has been redesigned and is being relaunched or when a lot of content has been added to it or changed, he said.

The newly-indexed pages should become searchable no later than 24 hours after the re-indexing is requested.