1. A computer apparatus for searching an in-memory database comprising: a plurality of compute nodes coupled for data communications through a global combining network with a buffer on each compute node, and each of the plurality of compute nodes having a processor and computer memory operatively coupled to the processor, the computer memory having disposed within it a portion of the in-memory database; a search mechanism in the computer memory that receives a non-unique search key and searches the portion of the in-memory database using the search key and places a local result in the buffer; and the search mechanism contributes to a database search result through a collective operation on the buffers of the combining network by combining data received from a child node with the contents of the buffer and passing a combined result to a parent node of the plurality of nodes.