1. A method for processing a data stream language program, the method comprising: storing, by an instrumentation analysis system, metadata describing a plurality of data streams; receiving a data stream language program comprising a set of instructions specified using a data stream language, the instructions comprising a find block and a set of blocks following the find block, the find block associated with a search expression, the search expression based on metadata attributes associated with data streams; repeatedly evaluating the search expression, each evaluation of the search expression identifying a set of data streams from the plurality of data streams conforming to the search expression, wherein the set of identified data streams is provided as input to the set of blocks following the find block; and repeatedly executing the set of blocks following the find block, the execution comprising: receiving data values from each data stream of the set of identified data streams, executing the set of blocks following the find block based on the received data values, generating one or more result data values based on the execution of the set of blocks, the result values corresponding to result data streams generated by the data stream language program, and storing the one or more result data values.