MS SQL Server is used as an experimental approach to examine the proposed techniques.Haxhijaha, BlertaAjdari, JauminRaufi, BujarZenuni, XhemalIsmaili, FlorieInternational Journal on Information Technologies & Security
最近一年一直在做PolarDB的并行优化器,过程中调研了各种分布式数据库系统的优化和执行框架,后续几篇文章将一一分享,首先介绍对PolarDB MySQL的并行优化框架影响最大的,也就是SQL Server PDW。 SQL Server PDW…
DSQL Generation Example 参考资料 总结 PDW QO是paper描述了SQL Server MPP查询优化器的设计与实现,Paralled Data Warehouse产品的查询优化器(PDW QO)。PDW QO是基于SQL Server单机Cascade优化器技术实现的针对分布式查询的CBO优化器。PDW QO在控制节点采用两阶段方式制定DPlan(分布式执行计划): 基于单机Cascade优化器...
Query optimization for such system is a challenging and important problem. In this paper we describe the Query Optimizer inside the SQL Server Parallel Data Warehouse product (PDW QO). We leverage existing QO technology in Microsoft SQL Server to implement a cost-based optimizer for distributed ...
For example, if a table had 1 billion rows, under the old behavior it would have taken 200 million rows to be changed before auto-stats update kicks in. In SQL Server 2016, it would take only 1 million rows to trigger auto stats update. ...
For example, Parameter Sensitive Plan (PSP) optimization was introduced in SQL Server 2022 (16.x) (compatibility level 160), which uses multiple active plans per query to address nonuniform data distributions. If your environment cannot use the latest compatibility level, Query Store hints using ...
Hardware Optimization: Fine-tune the MySQL server configuration to ensure that the MySQL instance is appropriately utilizing CPU cores and memory. The result:With these optimization efforts, there can be a significant decrease in the execution time of the complex query. Users will experience faster ...
Improved statistics loading framework: The optimizer internally improves the loading of statistics compared with SQL Server 2000. It now loads all and only the statistics it needs, improving optimization result quality and performance. Increased ability to automatically create statistics on computed columns...
Applies to:SQL Server (Starting with SQL Server 2022 (16.x)) DisablesOptimized plan forcingfor a query. Optimized plan forcing reduces compilation overhead for repeating forced queries. Once the query execution plan is generated, specific compilation steps are stored for reuse as an optimization re...
·Improved statistics loading framework:The optimizer internally improves the loading of statistics compared with SQL Server 2000. It now loads all and only the statistics it needs, improving optimization result quality and performance. ·Minimum sample size:A minimum of 8 megabytes (MB) of data, ...