This document will explain the DB join and spark join.
[TOC]
DB Join
SQL Join Types
Inner or Outer Joins
EQUI Join
NON EQUI Join (Theta Join)
Join Implementation
Nested Loop Join
Hash Join
Sort Merged Join
Optimizer – Select Join Strategy
Cost Model
Spark Join
Join Syntax
Supported Join Types
Join Methods
Shuffle Hash Join
Broadcast Hash Join (Map Join)
Spark SQL Config
Http broadcast VS TorrentBroadcast (Based on BitTorrent)
Driver Broadcast Join
Executor Broadcast Join
Shuffle Sort Merge Join (Default)
Cartesian Product Join (Shuffle Replicate Nested Loop Join)
Broadcast Nested Loop Join
Scenarios
Optimizer
CBO
Statistics Collection
Spark SQL Config
Operator Cost Formula
Mainly Operator Estimation
Benefits
Join Hints
Select Join Strategy
Spark 3.0 AQE
Dynamically coalesce shuffle partitions
Dynamically switch join strategies
Dynamically optimize skew joins
Suggestions
Reference
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