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[Institut fuer Informatik] [Leerraum] [Humboldt-Universitaet zu Berlin]
13.07.2015 13:15 Alter: 2 yrs

New Publication: "Selection on Modern CPUs" at IMDM Workshop by Steffen Zeuch and Johann-Christoph Freytag



Abstract: 

Current processor microarchitectures employ sophisticated

techniques such as speculative or out-of-order execution to

hide memory latencies and keep the processor pipeline fully

utilized. However, these techniques introduce a high com-

plexity and variance to the processing of database opera-

tions. In particular, these techniques are transparent to the

DBMS operations and fully controlled by the processor. To

fully utilize the sophisticated capabilities of modern CPUs,

it is necessary to understand their characteristics and adjust

database operations as well as cost models accordingly.

In this paper, we extensively examine the execution of

relation selection operations on modern hardware in an in-

depth performance analysis. We show, that the branching

behavior and the memory usage are the two main contribu-

tors to run-time. Based on these insights, we show how two

common cost models would predict the cost of a selection

and why they fall short in determining run-time behavior

for parallel execution. We reveal, that a cost model that

exploits only one performance parameter to determine exe-

cution costs is not able to predict the non-linear performance

characteristics of modern CPUs.