Result Merge

Introduction

A user has performed a search, query, or algorithm on two or more catalogues or datasets, and the results from each catalogue / dataset should be merged into one result set. Astrogrid accomplishes this task by selecting the fastest compute resource for the merge, transferring all data to that resource, joining the data there, and returning the result set to the user via MySpace (see MySpaceStoreResults).

Flow of Events

Astrogrid has already performed a search, query, or algorithm on two or more catalogues or datasets; this point is represented by the Query Façade. The Query Façade contacts the estimator to determine how long each data source would require to transfer its data to another compute resource, as well as how long the merge would take. This information is sent to the scheduler. The scheduler orders one or more data sources to transfer data to a compute resource that would complete the job quickest (and is satisfied by user permission). This compute resource may be any of the data resources or a third party compute resource. Once all data has been transferred to an appropriate compute resource, the data is joined and returned to the user. See MySpaceStoreResults.

Sequence Diagram

-- ElizabethAuden - 15 Jun 2002