| 20100076999 | DOCUMENT SEARCHING DEVICE AND DOCUMENT SEARCHING METHOD - In registering a new document file in an index, the accumulated percentage of the number of registered keys A from registered keys associated with one posting data, including registered data, is computed. The posting data of a registered key associated with the number of posting data items, which is at most a threshold N, is stored in a leaf page of a balanced-plus tree constituted of the registered keys, and the posting data of a registered key associated with the number of posting data items, which is greater than the threshold N, is stored in a page of a posting-storing unit. When the accumulated number i of registered documents is a predetermined document number, the threshold N of the number of posting data items is changed to the maximum number of the posting data items that are associated with a registered key where the accumulated percentage is less than 60 percent. | 03-25-2010 |
