In a search engine with two-dimensional scalable architecture for searching of a collection of documents, the search engine comprises data processing units which forms set of nodes connected in a network, a first set of nodes comprising dispatch nodes, a second set of nodes search nodes and a third set of nodes indexing nodes. The search nodes are grouped in columns, which via the network are connected in parallel between the dispatch nodes and an indexing node. The dispatch nodes are adapted for processing search queries and search answers, the search nodes are adapted to contain search software, at least some of the search nodes additionally including at least one search processor module and the indexing nodes are adapted for generally generating indexes for the search software. Optionally, acquisition nodes provided in a fourth set of nodes and adapted for processing the search answers, thus relieving the dispatch nodes of this task. The two-dimensional scaling takes place respectively through a scaling of the data volume and a scaling of the search engine performance through a respective adaptation of the architecture.