DPG: A Cache-Efficient Accelerator for Sorting and for Join Operators

TL;DR

This paper introduces DPG, a cache-efficient algorithm that accelerates sorting and join operations by optimizing record retrieval, significantly improving performance in main memory database operations.

Contribution

The paper presents DPG, a novel record retrieval algorithm that enhances sorting and join efficiency without relying on sorting or hashing, applicable to various database tasks.

Findings

DPG accelerates sorting by optimizing the final copying phase.

DPG enables faster foreign key joins without sorting or hashing.

The approach extends to spatial and temporal database retrievals.

Abstract

We present a new algorithm for fast record retrieval, distribute-probe-gather, or DPG. DPG has important applications both in sorting and in joins. Current main memory sorting algorithms split their work into three phases: extraction of key-pointer pairs; sorting of the key-pointer pairs; and copying of the original records into the destination array according the sorted key-pointer pairs. The copying in the last phase dominates today's sorting time. Hence, the use of DPG in the third phase provides an accelerator for existing sorting algorithms. DPG also provides two new join methods for foreign key joins: DPG-move join and DPG-sort join. The resulting join methods with DPG are faster because DPG join is cache-efficient and at the same time DPG join avoids the need for sorting or for hashing. The ideas presented for foreign key join can also be extended to faster record pair retrieval for spatial and temporal databases.