Main-Memory Hash Joins on Modern Processor Architectures
Abstract:
Existing main-memory hash join algorithms for multi-core can be classified into two camps. Hardware-oblivious hashjoin variants do not depend on hardware-specific parameters. Rather, they consider qualitative characteristics of modern hardwareand are expected to achieve good performance on any technologically similar platform. The assumption behind these algorithms isthat hardware is now good enough at hiding its own limitations—through automatic hardware prefetching, out-of-order execution, orsimultaneous multi-threading (SMT)—to make hardware-oblivious algorithms competitive without the overhead of carefully tuning to theunderlying hardware. Hardware-conscious implementations, such as (parallel) radix join, aim to maximally exploit a given architectureby tuning the algorithm parameters (e.g., hash table sizes) to the particular features of the architecture. The assumption here is thatexplicit parameter tuning yields enough performance advantages to warrant the effort required.
This paper compares the two approaches under a wide range of workloads (relative table sizes, tuple sizes, effects of sorted data,etc.) and configuration parameters (VM page sizes, number of threads, number of cores, SMT, SIMD, prefetching, etc.). The resultsshow that hardware-conscious algorithms generally outperform hardware-oblivious ones. However, on specific workloads and specialarchitectures with aggressive simultaneous multi-threading, hardware-oblivious algorithms are competitive. The main conclusion of thepaper is that, in existing multi-core architectures, it is still important to carefully tailor algorithms to the underlying hardware to get thenecessary performance. But processor developments may require to revisit this conclusion in the future.
Existing system:
Existing main-memory hash join algorithms for multi-core can be classified into two camps. Hardware-oblivious hashjoin variants do not depend on hardware-specific parameters. Rather, they consider qualitative characteristics of modern hardwareand are expected to achieve good performance on any technologically similar platform. The assumption behind these algorithms isthat hardware is now good enough at hiding its own limitations—through automatic hardware prefetching, out-of-order execution, orsimultaneous multi-threading (SMT)—to make hardware-oblivious algorithms competitive without the overhead of carefully tuning to theunderlying hardware. Hardware-conscious implementations, such as (parallel) radix join, aim to maximally exploit a given architectureby tuning the algorithm parameters (e.g., hash table sizes) to the particular features of the architecture. The assumption here is thatexplicit parameter tuning yields enough performance advantages to warrant the effort required.
Proposed system:
This paper compares the two approaches under a wide range of workloads (relative table sizes, tuple sizes, effects of sorted data,etc.) and configuration parameters (VM page sizes, number of threads, number of cores, SMT, SIMD, prefetching, etc.). The resultsshow that hardware-conscious algorithms generally outperform hardware-oblivious ones. However, on specific workloads and specialarchitectures with aggressive simultaneous multi-threading, hardware-oblivious algorithms are competitive. The main conclusion of thepaper is that, in existing multi-core architectures, it is still important to carefully tailor algorithms to the underlying hardware to get thenecessary performance. But processor developments may require to revisit this conclusion in the future.
SYSTEM REQUIREMENTS:
HARDWARE REQUIREMENTS:
System: Pentium IV 2.4 GHz.
Hard Disk : 40 GB.
Floppy Drive: 1.44 Mb.
Monitor: 15 VGA Colour.
Mouse: Logitech.
Ram: 512 Mb.
SOFTWARE REQUIREMENTS:
Operating system : Windows XP/7.
Coding Language: JAVA/J2EE
IDE:Netbeans 7.4
Database:MYSQL
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