11. The method of claim 10 , wherein the query layer agent executes the plurality of sub-queries by designating each of the plurality of sub-queries to a work thread processor within a pool of work thread processors, and wherein each work thread processor in the pool executes zero, one, or a plurality of the plurality of sub-queries constituting the optimized database query.
10. The method of claim 1 , wherein executing the optimized database query against the multi-tenant database system to retrieve the data comprises: designating the data to be retrieved as a massive data set based on a comparison of an estimated or actual size of the data to be retrieved against a massive query threshold; breaking up the optimized database query into a plurality of optimized sub-queries, each optimized sub-query corresponding to a portion of the massive data set; allocating execution of the plurality of optimized sub-queries to one work thread processor within a pool of work thread processors, wherein the one work thread processor to establish a spooling algorithm internal to the one work thread processor to spool/cache one or more portions of the massive data set returned to the one work thread processor responsive to execution of one or more of the plurality of optimized sub-queries, and wherein the spooling algorithm retrieves a re-requested portion of the massive data set from the spool/cache, when available, in place of re-executing a corresponding optimized sub-query to retrieve the re-requested portion.