Adaptive Cost Model for Query Optimization

Fuente: arXiv
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Autori principali: Vasilenko, Nikita, Demin, Alexander, Ponomaryov, Denis
Natura: Preprint
Pubblicazione: 2024
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author Vasilenko, Nikita
Demin, Alexander
Ponomaryov, Denis
author_facet Vasilenko, Nikita
Demin, Alexander
Ponomaryov, Denis
contents The principal component of conventional database query optimizers is a cost model that is used to estimate expected performance of query plans. The accuracy of the cost model has direct impact on the optimality of execution plans selected by the optimizer and thus, on the resulting query latency. Several common parameters of cost models in modern DBMS are related to the performance of CPU and I/O and are typically set by a database administrator upon system tuning. However these performance characteristics are not stable and therefore, a single point estimation may not suffice for all DB load regimes. In this paper, we propose an Adaptive Cost Model (ACM) which dynamically optimizes CPU- and I/O-related plan cost parameters at DB runtime. By continuously monitoring query execution statistics and the state of DB buffer cache ACM adjusts cost parameters without the need for manual intervention from a database administrator. This allows for responding to changes in the workload and system performance ensuring more optimal query execution plans. We describe the main ideas in the implementation of ACM and report on a preliminary experimental evaluation showing 20\% end-to-end latency improvement on TPC-H benchmark.
format Preprint
id arxiv_https___arxiv_org_abs_2409_17136
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Adaptive Cost Model for Query Optimization
Vasilenko, Nikita
Demin, Alexander
Ponomaryov, Denis
Databases
68T05, 68P15
The principal component of conventional database query optimizers is a cost model that is used to estimate expected performance of query plans. The accuracy of the cost model has direct impact on the optimality of execution plans selected by the optimizer and thus, on the resulting query latency. Several common parameters of cost models in modern DBMS are related to the performance of CPU and I/O and are typically set by a database administrator upon system tuning. However these performance characteristics are not stable and therefore, a single point estimation may not suffice for all DB load regimes. In this paper, we propose an Adaptive Cost Model (ACM) which dynamically optimizes CPU- and I/O-related plan cost parameters at DB runtime. By continuously monitoring query execution statistics and the state of DB buffer cache ACM adjusts cost parameters without the need for manual intervention from a database administrator. This allows for responding to changes in the workload and system performance ensuring more optimal query execution plans. We describe the main ideas in the implementation of ACM and report on a preliminary experimental evaluation showing 20\% end-to-end latency improvement on TPC-H benchmark.
title Adaptive Cost Model for Query Optimization
topic Databases
68T05, 68P15
url https://arxiv.org/abs/2409.17136