Abstract:
A multiversioned position-space indexing system is disclosed. The system includes data structures for maintaining a multiversioned position space including a multi-versioned filter merge list which represents many versions of a changing position space in a very compact form and a position shift map which describes how to translate stored positions in many different log-structured merge tree layers into logical positions at a particular timestamp. Each log-structured merge tree layer can be divided into two sublayers: a final sublayer and a correction sublayer. The final sublayer contains index entries added after the layer's start timestamp and remain live as of the layer's final timestamp as well as deletion makers for index entries that were inserted before the layer's start timestamp, but deleted before the layer's final timestamp. The correction layer contains index entries that were both created and deleted between the start and end timestamps of the layer.
Abstract:
In an online advertising system, advertisers compete with each other for advertising space. There may be multiple advertising positions available, where the placement of advertisements is determined by an auction. To encourage competition, some advertisements may be presented with enhanced features. These enhanced features create an incentive for which advertisers can compete, thereby increasing the effectiveness, usefulness and/or profitability of the advertising system. The application of enhanced features may be determined using at least one or more of pricing information, performance information and advertising information.