Asynchronous log ## PD/TiKV (2/2) • Fix DST issue • Batch Split, Fast Split ## SQL Layer (1/2) ## • Optimizer && Execution Engine ○ Optimize the selection range of `Index Join` to improve the execution generation storage engine ☐ Optimize for large key-value ☐ Compaction ## TiDB • Optimizer ○ Join Reorder Cascades Optimizer • Execution Engine ☐ Parallel operators ☐ Projection pushdown ☐ Improve the

Established 2297 50.3. The Parser Stage 2298 50.4. The PostgreSQL Rule System 2299 50.5. Planner/Optimizer 2299 50.6. Executor 2300 51. System Catalogs 2302 51.1. Overview 2302 51.2. pg_aggregate Creating Custom Scan Plans ..... 2487 59.3. Executing Custom Scans ..... 2488 60. Genetic Query Optimizer ..... 2491 60.1. Query Handling as a Complex Optimization Problem ..... 2491 60.2. Genetic Algorithms exceptions to this rule are leakproof functions, which are guaranteed to not leak information; the optimizer may choose to apply such functions ahead of the row-security check.) Rows for which the expression

• Custom HTTP Handler • MySQL Database Engine • BloomFilter Skipping Index • Query Predicate Optimizer • And more ~ 400+ commit ![Image](/uploads/documents/f/9/9/6/f9963fdbc42de31b6645b98c8344939c/p2_1

Resolved Issues 152 Server 152 Query Optimizer 152 Data Flow 152 PostGIS 153 Release 6.19.2 153 Changed Features 153 Resolved Issues 153 Server 153 Query Optimizer 153 Cluster Management 153 Data Data Flow 154 Release 6.19.1 154 Changed Features 154 Resolved Issues 154 Server 154 Query Optimizer 155 Cluster Management 155 Release 6.19.0 155 Features 156 Resolved Issues 156 Cluster Management 6.18.1 158 Resolved Issues 158 Server 158 Query Optimizer 159 Release 6.18.0 159 Features 159 Resolved Issues 160 Server 160 Query Optimizer 162 Cluster Management 162 Data Loading 163 Release

6.18.1 150 Resolved Issues 150 Server 150 Query Optimizer 151 Release 6.18.0 151 Features 151 Resolved Issues 152 Server 152 Query Optimizer 154 Cluster Management 154 Data Loading 155 Release Planner 156 Release 6.17.4 156 Resolved Issues 156 Query Optimizer 156 Server 156 Release 6.17.3 156 Resolved Issues 157 Query Optimizer 157 Server 157 Release 6.17.2 157 Resolved Issues 157 Cluster Cluster Management 157 Extensions 157 Query Optimizer 157 Server 158 gpload 158 Release 6.17.1 158 Resolved Issues 158 Postgres Planner 158 Query Optimizer 159 Server 159 Release 6.17.0 159 Features

优化器非常非常重要 ➢ 基于规则优化和基于代价优化 ## ORCA ➢ 历时十年，独立开发 ➢ Cascades 架构 OLAP性能很棒 https://db.cs.cmu.edu/events/vaccination-2022-orca-a-modular-query-optimizer-architecture-for-vmware-greenplum-venky-raghavan/ ## Train-Test Split ## User Interface “Driver” Functions (outer loops of iterative algorithms, optimizer invocations) High-level Abstraction Layer (iteration controller, ...) SQL, generated from specification

Identify the performance bottleneck of the query 402 8.3.2 Analyze system issues 403 8.3.3 Analyze optimizer issues 410 8.4 SQL Diagnostics 410 8.4.1 Overview 411 8.4.2 Cluster information tables 411 What's the trigger strategy for auto analyze in TiDB? 2350 13.2.17 Can I use hints to override the optimizer behavior? 2350 13.2.18 Why the Information schema is changed error is reported? 2351 13.2.19 variable setting cannot be changed without restarting the TiDB server. Controls whether to ignore the optimizer's cost estimation and to forcibly use the MPP mode for query execution. The data type of this

Identify the performance bottleneck of the query 438 8.3.2 Analyze system issues 439 8.3.3 Analyze optimizer issues 446 8.4 SQL Diagnostics 446 8.4.1 Overview 447 8.4.2 Cluster information tables 447 What's the trigger strategy for auto analyze in TiDB? 2533 13.2.17 Can I use hints to override the optimizer behavior? 2533 13.2.18 Why the Information schema is changed error is reported? 2533 13.2.19 Variable name Change type Description tidb_enable_Newly_added_controls_this behavior of the optimizer when the statistics on a table expire. The default value is ON. When the number of modified rows

Identify the performance bottleneck of the query 418 8.3.2 Analyze system issues 419 8.3.3 Analyze optimizer issues 426 8.4 SQL Diagnostics 426 8.4.1 Overview 427 8.4.2 Cluster information tables 427 What's the trigger strategy for auto analyze in TiDB? 2422 13.2.17 Can I use hints to override the optimizer behavior? 2422 13.2.18 Why the Information schema is changed error is reported? 2423 13.2.19 functions in expression indexes to greatly improve query performance • Improve the accuracy of optimizer cardinality estimation to help to select optimal execution plans • Announce the general availability

performance bottleneck of the query ··· 983 10.3.2 Analyze system issues ··· 984 10.3.3 Analyze optimizer issues ··· 991 10.4 SQL Diagnostics ··· 991 10.4.1 Overview ··· 992 10.4.2 Cluster information What’s the trigger strategy for auto analyze in TiDB? ... 3871 15.3.20 Can I use optimizer hints to override the optimizer behavior? ... 3871 15.3.21 Why the Information schema is changed error is reported loads. User document, #95 - Support the join order hint syntax - The LEADING hint reminds the optimizer to use the specified order as the prefix of join operations. A good prefix of join can quickly reduce