The most confusing of these columns are those related to tempdb. Each of the columns reports a number of 8 KB pages. The [tempdb_allocations] column is collected directly from the tempdb-related DMVs, and indicates how many pages were allocated in tempdb due to temporary tables, LOB types, spools, or other consumers. The [tempdb_current] column is computed by subtracting the deallocated pages information reported by the tempdb DMVs from the number of allocations. Seeing a high number of allocations with a small amount of current pages means that your query may be slamming tempdb, but is not causing it to grow. Seeing a large number of current pages means that your query may be responsible for all of those auto-grows you keep noticing.