There's no Moore's law to sum up the growth curve of databases. But here's a rule of thumb: The amount of data stored by businesses nearly doubles every 12 to 18 months. And the very biggest--those at or near the 100-terabyte mark--probably triple every three years.
But databases aren't just getting bigger. They're also becoming more real time. Wal-Mart Stores Inc. refreshes sales data hourly, adding a billion rows of data a day, allowing more complex searches. EBay Inc. lets insiders search auction data over short time periods to get deeper insight into what affects customer behavior. Data is also coming from increasingly complex sources: Radio-frequency identification readers now feed data to Wal-Mart, and Nielsen Media Research, in collecting info on TV-viewing habits, is getting data from TiVos and iPods along with the standard living-room set.
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