cost estimation

Sanyou's Java Diary

Mar 27, 2025 · Databases

Why Your MySQL Indexes Fail: Cost Estimation, Fragmentation, and Slow Query Secrets

This article examines MySQL slow‑query troubleshooting, explaining how the optimizer estimates costs, why indexes may be ineffective even when present, the impact of memory fragmentation, pitfalls of prefix indexes, index merging techniques, and additional resource‑related factors that can cause seemingly healthy SQL statements to become slow.

Index OptimizationMySQLcost estimation

0 likes · 11 min read

Why Your MySQL Indexes Fail: Cost Estimation, Fragmentation, and Slow Query Secrets

Zhuanzhuan Tech

Mar 26, 2025 · Databases

MySQL Cost Evaluation, Index Pitfalls, and Memory Fragmentation in Slow Query Optimization

This article examines MySQL's cost estimation process, explains why added indexes may still be ineffective, discusses the impact of memory fragmentation, and presents practical techniques such as prefix index handling, index merging, and resource monitoring to improve slow‑query performance.

Index OptimizationMySQLcost estimation

0 likes · 10 min read

MySQL Cost Evaluation, Index Pitfalls, and Memory Fragmentation in Slow Query Optimization

Aikesheng Open Source Community

Feb 29, 2024 · Databases

Optimizing Nested-Loop Join Performance in OceanBase: Analysis, Rewrites, and Results

This article analyzes a slow Join query on OceanBase 3.2.3.3, examines execution plans and table statistics, proposes two rewrite methods—adding a filter condition and using a hash‑join hint—and demonstrates how these changes reduce execution time from over 500 seconds to just a few seconds.

Join OptimizationOceanBaseSQL

0 likes · 12 min read

Optimizing Nested-Loop Join Performance in OceanBase: Analysis, Rewrites, and Results

Java Architect Essentials

Apr 18, 2023 · Databases

How MySQL Calculates Execution Cost for Index Selection and Why It May Choose Suboptimal Plans

This article explains how MySQL estimates the I/O and CPU costs of different indexes when executing COUNT(*) and other queries, demonstrates the calculations with a concrete example on a 100k‑row table, and shows why the optimizer sometimes picks a full‑table scan over a seemingly better index.

EXPLAINIndex OptimizationMySQL

0 likes · 10 min read

How MySQL Calculates Execution Cost for Index Selection and Why It May Choose Suboptimal Plans

DataFunTalk

Mar 31, 2023 · Artificial Intelligence

Estimating the Resource and Cost Requirements for Large Language Model Training and Inference

The article analyses the computational resources, hardware costs, and human investment needed to train and serve large language models such as GPT‑3, discusses practical cost calculations, highlights the challenges faced by Chinese AI teams, and argues for sustained, long‑term funding to achieve meaningful breakthroughs.

AI infrastructureChina AIInference

0 likes · 14 min read

Estimating the Resource and Cost Requirements for Large Language Model Training and Inference

Aikesheng Open Source Community

Mar 1, 2021 · Databases

Understanding MySQL EXPLAIN FORMAT=JSON Cost Details and Calculations

This article explains how to use MySQL's EXPLAIN FORMAT=JSON to view detailed execution plan costs, illustrates table structures, walks through two query examples with cost breakdowns, and clarifies the calculation of read_cost and eval_cost for both simple and join queries.

EXPLAINJSONMySQL

0 likes · 10 min read

Understanding MySQL EXPLAIN FORMAT=JSON Cost Details and Calculations

360 Tech Engineering

Jan 7, 2019 · Databases

Understanding Relational Optimizer and Database Statistics for SQL Performance

This article explains the fundamentals of relational optimization, the role of the optimizer, how CPU and I/O costs are estimated, and why accurate database statistics are essential for effective SQL performance tuning.

Database StatisticsPerformance TuningRelational Optimizer

0 likes · 8 min read

Understanding Relational Optimizer and Database Statistics for SQL Performance