join strategies — 4 Technical Articles

Nov 4, 2024 · Databases

Detailed Analysis of Doris SQL Execution Process: Optimizer, Scheduler, and Executor

This article provides a comprehensive walkthrough of Doris's SQL execution pipeline, covering the query optimizer's parsing, rewriting, and plan generation, the scheduler's fragment distribution, and the executor's fragment processing, including code examples of expression rewrite rules, join strategies, and data flow between FE and BE nodes.

Distributed ExecutionQuery OptimizerSQL

0 likes · 30 min read

Detailed Analysis of Doris SQL Execution Process: Optimizer, Scheduler, and Executor

Alibaba Cloud Developer

Jan 11, 2024 · Big Data

Unlock ODPS SQL Performance: Deep Dive into Execution Plans & Optimizations

This article examines ODPS SQL performance by dissecting logical execution plans and Logview visualizations, explaining the underlying principles of various optimization techniques such as multi‑distinct handling, shuffle reduction, system parameters, and different join strategies, and demonstrates how to apply these methods to improve query efficiency in real‑world data engineering tasks.

ODPSShuffleexecution plan

0 likes · 17 min read

Unlock ODPS SQL Performance: Deep Dive into Execution Plans & Optimizations

Big Data Technology & Architecture

Aug 15, 2021 · Big Data

Spark SQL Interview Guide: Concepts, APIs, Optimization and Common Pitfalls

This article provides a comprehensive overview of Spark SQL, covering its architecture, DataSet/DataFrame APIs, code examples for creating and querying datasets, join strategy selection, handling Hive tables, small‑file issues, inefficient NOT‑IN subqueries, Cartesian products, and a catalog of useful built‑in functions.

DataFrameDatasetHive Integration

0 likes · 40 min read

Spark SQL Interview Guide: Concepts, APIs, Optimization and Common Pitfalls

Programmer DD

Nov 21, 2019 · Databases

Why Alibaba’s Java Handbook Limits Joins and How to Write Efficient SQL

The article explains why the Alibaba Java Development Manual restricts joins to three tables, discusses MySQL’s join algorithm limitations, and offers practical alternatives such as query decomposition, denormalization, and using IN or hash joins to improve performance.

DenormalizationMySQLSQL Optimization

0 likes · 6 min read

Why Alibaba’s Java Handbook Limits Joins and How to Write Efficient SQL