Physical Database Design

310 CHAPTER 13 Down to the Metal: Server Resources and Topology

converged, the database has reserved more than 8 GB of memory for sorting. As is illus-

trated in Figure 13.22, this memory distribution shift has a dramatic effect on the work-

load performance.

Figure 13.22 shows the workload performance during the run. In the first stage of

the run, the memory distribution is stable as the 16 streams of query 13 complete con-

sistently in about 280 seconds. Once the workload shifts, however, it is clear that the

system’s memory is not properly configured for query 21. At this point, STMM begins

redistributing the database memory and the resultant dramatic ...