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optimizer

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DataFunSummit
DataFunSummit
Mar 12, 2025 · Big Data

Principles and Common Optimization Techniques of the Spark SQL Optimizer

This article explains the underlying principles of the Spark SQL optimizer and presents three classic optimization paradigms—push‑down optimization, operator elimination/merging, and expression elimination/replacement—illustrating each with concrete rule implementations and code examples.

Big DataQuery Optimizationoptimizer
0 likes · 12 min read
Principles and Common Optimization Techniques of the Spark SQL Optimizer
Lobster Programming
Lobster Programming
Oct 5, 2024 · Databases

How MySQL Chooses the Cheapest Execution Plan: Cost Model Explained

This article explains MySQL's layered architecture, how the optimizer generates multiple execution plans, evaluates their I/O and engine costs, and selects the plan with the lowest total cost, illustrated with example queries, cost tables, and JSON output.

MySQLSQLcost model
0 likes · 9 min read
How MySQL Chooses the Cheapest Execution Plan: Cost Model Explained
Zhuanzhuan Tech
Zhuanzhuan Tech
Mar 6, 2024 · Databases

Diagnosing and Resolving MySQL Optimizer Mis‑selection of Indexes

This article recounts a real‑world incident where MySQL 5.7 chose a sub‑optimal index, causing a three‑second slow query, and explains how the team identified the root cause, used EXPLAIN and optimizer trace, and applied fixes such as forced index hints and data cleanup.

EXPLAINIndex SelectionMySQL
0 likes · 11 min read
Diagnosing and Resolving MySQL Optimizer Mis‑selection of Indexes
Aikesheng Open Source Community
Aikesheng Open Source Community
Mar 21, 2023 · Databases

MySQL 8.0 New Features: Performance, Security, Optimizer, and Other Enhancements

This article provides a comprehensive overview of MySQL 8.0 enhancements, covering performance improvements such as contention‑aware scheduling and hash joins, security upgrades including authentication plugins and password policies, optimizer refinements, and various other features like persistent variables, GIS support, and binlog expiration handling.

Hash JoinJSONMySQL
0 likes · 16 min read
MySQL 8.0 New Features: Performance, Security, Optimizer, and Other Enhancements
DataFunSummit
DataFunSummit
Feb 14, 2023 · Artificial Intelligence

Deep Learning Hyperparameter Tuning and Training Tips: Insights from Zhihu Experts

This article compiles practical deep learning training and hyperparameter tuning advice from Zhihu contributors, covering model debugging, learning‑rate strategies, optimizer choices, data preprocessing, regularization techniques, initialization methods, common pitfalls, recommended research papers, and ensemble approaches.

deep learninggradient clippinghyperparameter tuning
0 likes · 13 min read
Deep Learning Hyperparameter Tuning and Training Tips: Insights from Zhihu Experts
Aikesheng Open Source Community
Aikesheng Open Source Community
Aug 1, 2022 · Databases

MySQL SELECT Query Crash Analysis and Resolution

This article investigates a MySQL crash triggered by a specific SELECT statement, analyzes the stack trace and optimizer behavior that leads to an invalid memory access, and presents three practical solutions including disabling DuplicateWeedout, upgrading MySQL, and normalizing table character sets.

DuplicateWeedoutMySQLTroubleshooting
0 likes · 7 min read
MySQL SELECT Query Crash Analysis and Resolution
Python Programming Learning Circle
Python Programming Learning Circle
Jan 11, 2022 · Artificial Intelligence

Dynamic Learning Rate Adjustment in PyTorch: Optimizer Basics and Scheduler Usage

This article explains how to configure and use PyTorch optimizers, their attributes and methods, and demonstrates various learning‑rate scheduling techniques—including manual updates and built‑in schedulers such as LambdaLR, StepLR, MultiStepLR, ExponentialLR, CosineAnnealingLR, and ReduceLROnPlateau—through clear code examples.

PyTorchSchedulerdeep learning
0 likes · 14 min read
Dynamic Learning Rate Adjustment in PyTorch: Optimizer Basics and Scheduler Usage
Tencent Cloud Developer
Tencent Cloud Developer
Sep 29, 2021 · Fundamentals

Building a Simple LLVM-Based Compiler: Lexer, Parser, SSA, Optimizer, JIT and Mutable Variables

The tutorial walks through building a complete LLVM‑based Kaleidoscope compiler—from a tokenizing lexer and recursive‑descent parser, through AST construction, LLVM IR generation with SSA and phi nodes, optimization passes, JIT execution, and mutable variable handling via stack allocation—providing full C++ source examples.

CompilerJITKaleidoscope
0 likes · 47 min read
Building a Simple LLVM-Based Compiler: Lexer, Parser, SSA, Optimizer, JIT and Mutable Variables
Full-Stack Internet Architecture
Full-Stack Internet Architecture
Sep 26, 2021 · Databases

Why MySQL Optimizer Chooses a Full Table Scan for ORDER BY id ASC LIMIT 1 and How to Force the Correct Index

The article analyzes a MySQL optimizer bug where a query with ORDER BY id ASC LIMIT 1 triggers a full‑table scan despite an applicable idx_uid_stat index, explains the cost‑based decision process, and presents two practical work‑arounds—using FORCE INDEX or a harmless arithmetic expression—to ensure the index is used.

Full Table ScanMySQLSQL
0 likes · 7 min read
Why MySQL Optimizer Chooses a Full Table Scan for ORDER BY id ASC LIMIT 1 and How to Force the Correct Index
Aikesheng Open Source Community
Aikesheng Open Source Community
Sep 10, 2021 · Databases

Understanding MySQL 8.0 Derived Condition Pushdown Optimization and Its Impact on User Variables

The article explains MySQL 8.0.22's new optimizer_switch variable derived_condition_pushdown, shows how enabling it can cause unexpected results with user‑defined variables in outer WHERE clauses, provides test cases, explains the underlying behavior, and offers three practical solutions.

MySQLOptimizer SwitchUser Variables
0 likes · 7 min read
Understanding MySQL 8.0 Derived Condition Pushdown Optimization and Its Impact on User Variables
Architecture Digest
Architecture Digest
Sep 13, 2020 · Databases

MySQL 8.0 Version History and New Features

An overview of MySQL 8.0’s release timeline, including major GA versions, and a detailed summary of its new capabilities such as transactional data dictionary, atomic DDL, enhanced security, role support, InnoDB improvements, JSON enhancements, optimizer extensions, backup lock, connection management, and other performance and management features.

8.0FeaturesInnoDB
0 likes · 10 min read
MySQL 8.0 Version History and New Features
DevOps Cloud Academy
DevOps Cloud Academy
Nov 20, 2019 · Databases

SOAR (SQL Optimizer And Rewriter): Installation, Configuration, and Practical Use Cases

This article introduces Xiaomi's open‑source SOAR tool, explains how to download and install the binary or source versions, walks through quick‑start commands, details key YAML configuration options and output formats, and describes four typical usage scenarios for SQL optimization and rewriting.

DatabaseSOARSQL
0 likes · 7 min read
SOAR (SQL Optimizer And Rewriter): Installation, Configuration, and Practical Use Cases
Aikesheng Open Source Community
Aikesheng Open Source Community
Jul 23, 2019 · Databases

MySQL 8.0.17 Release Highlights: Cloning, JSON Multi‑Value Indexes, Optimizer Improvements, and More

MySQL 8.0.17 introduces server cloning via MySQL Shell, multi‑value indexes for JSON arrays, enhanced JSON schema validation, optimizer and Volcano iterator upgrades, new collations, replication and routing enhancements, plus numerous bug fixes and deprecations, all detailed in the official release notes.

CloningDatabaseJSON Index
0 likes · 8 min read
MySQL 8.0.17 Release Highlights: Cloning, JSON Multi‑Value Indexes, Optimizer Improvements, and More
Efficient Ops
Efficient Ops
Oct 10, 2018 · Databases

Boost Your Database Reliability with Xiaomi’s Open‑Source SQL Optimizer SOAR

Xiaomi is open‑sourcing its Go‑based SQL Optimizer and Rewriter (SOAR) at OSCAR Days, a tool that automatically checks SQL quality, suggests index improvements, rewrites queries, provides EXPLAIN analysis, and integrates with editor plugins and a web self‑audit platform to boost database reliability and developer productivity.

DatabaseGoOpen-source
0 likes · 5 min read
Boost Your Database Reliability with Xiaomi’s Open‑Source SQL Optimizer SOAR
Qunar Tech Salon
Qunar Tech Salon
Aug 16, 2017 · Artificial Intelligence

Applying Wide & Deep Learning to Meituan‑Dianping Recommendation System

This article describes how Meituan‑Dianping leverages deep learning, especially the Wide & Deep model, to improve its recommendation system by addressing business diversity, user context, feature engineering challenges, optimizer and loss function choices, and presents offline and online experimental results showing significant CTR gains.

Feature Engineeringctrdeep learning
0 likes · 22 min read
Applying Wide & Deep Learning to Meituan‑Dianping Recommendation System