Sign InTry Free

SQL Tuning Overview

SQL is a declarative language. That is, an SQL statement describes what the final result should look like and not a set of steps to execute in sequence. TiDB will optimize the execution, and is semantically permitted to execute parts of the query in any order provided that it correctly returns the final result as described.

A useful comparison to SQL optimization, is to describe what happens when you use GPS navigation. From your provided address, 2955 Campus Drive San Mateo CA 94403, the GPS software plans the most time-efficient way to route you. It may make use of various statistics such as previous trips, meta data such as speed limits, and in modern cases, a live feed of traffic information. Several of these analogies translate to TiDB.

This section introduces several concepts about query execution:

  • Understanding the Query Execution Plan introduces how to use the EXPLAIN statement to understand how TiDB has decided to execute a statement.
  • SQL Optimization Process introduces what optimizations TiDB is capable of using to improve query execution performance.
  • Control Execution Plans introduces ways to control the generation of the execution plan. This can be useful in cases where the execution plan decided by TiDB is suboptimal.

Was this page helpful?

Download PDFRequest docs changesAsk questions on Discord
Playground
New
One-stop & interactive experience of TiDB's capabilities WITHOUT registration.
Products
TiDB
TiDB Dedicated
TiDB Serverless
Pricing
Get Demo
Get Started
© 2024 PingCAP. All Rights Reserved.
Privacy Policy.