releases: add TiDB 7.1.0 release notes (stable version)

releases/release-7.1.0.md

@@ -5,13 +5,13 @@ summary: Learn about the new features, compatibility changes, improvements, and
 
 # TiDB 7.1.0 Release Notes
 
-TiDB version: 7.1.0 (upcoming)
+Release date: xxxx
 
-> **Note:**
->
-> TiDB v7.1.0 is not yet available. This release note is a preview version to provide insights into upcoming features and is subject to change. The features outlined here are not guaranteed to be included in the final release.
+TiDB version: 7.1.0 (LTS)
+
+Quick access: [Quick start](https://docs.pingcap.com/tidb/v7.1/quick-start-with-tidb) | [Production deployment](https://docs.pingcap.com/tidb/v7.1/production-deployment-using-tiup) | [Installation packages](https://www.pingcap.com/download/?version=v7.1.0#version-list)
 
-In v7.1.0, the key new features and improvements are as follows:
+In v7.1.0-LTS, the key new features and improvements are as follows:
 
 <table>
 <thead>
@@ -52,6 +52,16 @@ In v7.1.0, the key new features and improvements are as follows:
 
 ### Performance
 
+* Enhance the Partitioned Raft KV storage engine (experimental) [#11515](https://github.com/tikv/tikv/issues/11515) [#12842](https://github.com/tikv/tikv/issues/12842) @[busyjay](https://github.com/busyjay) @[tonyxuqqi](https://github.com/tonyxuqqi) @[tabokie](https://github.com/tabokie) @[bufferflies](https://github.com/bufferflies) @[5kbpers](https://github.com/5kbpers) @[SpadeA-Tang](https://github.com/SpadeA-Tang) @[nolouch](https://github.com/nolouch) **tw:Oreoxmt**
+
+    TiDB v6.6.0 introduces the Partitioned Raft KV storage engine as an experimental feature, which uses multiple RocksDB instances to store TiKV Region data, and the data of each Region is independently stored in a separate RocksDB instance. The new storage engine can better control the number and level of files in the RocksDB instance, achieve physical isolation of data operations between Regions, and support stably managing more data. Compared with the original TiKV storage engine, using the Partitioned Raft KV storage engine can achieve about twice the write throughput, three times the read throughput, and reduce the elastic scaling time by about 4/5 under the same hardware conditions and mixed read and write scenarios.
+
+    In TiDB v7.1.0, the Partitioned Raft KV storage engine is compatible with TiFlash and supports tools such as TiDB Lightning, BR, and TiCDC.
+
+    Currently, this feature is experimental and not recommended for use in production environments. You can only use this engine in a newly created cluster and you cannot directly upgrade from the original TiKV storage engine.
+
+    For more information, see [documentation](/partitioned-raft-kv.md).
+
 * TiFlash supports late materialization (GA) [#5829](https://github.com/pingcap/tiflash/issues/5829) @[Lloyd-Pottiger](https://github.com/Lloyd-Pottiger)
 
      In v7.0.0, late materialization was introduced in TiFlash as an experimental feature for optimizing query performance. This feature is disabled by default (the [`tidb_opt_enable_late_materialization`](/system-variables.md#tidb_opt_enable_late_materialization-new-in-v700) system variable defaults to `OFF`). When processing a `SELECT` statement with filter conditions (`WHERE` clause), TiFlash reads all the data from the columns required by the query, and then filters and aggregates the data based on the query conditions. When Late materialization is enabled, TiDB supports pushing down part of the filter conditions to the TableScan operator. That is, TiFlash first scans the column data related to the filter conditions that are pushed down to the TableScan operator, filters the rows that meet the condition, and then scans the other column data of these rows for further calculation, thereby reducing IO scans and computations of data processing.
@@ -84,6 +94,18 @@ In v7.1.0, the key new features and improvements are as follows:
 
     For more information, see [documentation](/sql-non-prepared-plan-cache.md).
 
+* Support the DDL distributed parallel execution framework [#41495](https://github.com/pingcap/tidb/issues/41495) @[benjamin2037](https://github.com/benjamin2037) **tw:ran-huang**
+
+    Before TiDB v7.1.0, only one TiDB node can serve as the DDL owner and execute DDL tasks at the same time. Starting from TiDB v7.1.0, in the new distributed parallel execution framework, multiple TiDB nodes can execute the same DDL task in parallel, thus better utilizing the resources of the TiDB cluster and significantly improving the performance of DDL. In addition, you can linearly improve the performance of DDL by adding more TiDB nodes. Note that this feature is currently experimental and only supports `ADD INDEX` operations.
+
+    To use the distributed framework, set the value of [`tidb_enable_dist_task`](/system-variables.md#tidb_enable_dist_task) to `ON`:
+
+    ```sql
+    SET GLOBAL tidb_enable_dist_task = ON;
+    ```
+
+    For more information, see [documentation](/tidb-distributed-execution-framework.md).
+
 ### Reliability
 
 * Resource Control becomes generally available (GA) [#38825](https://github.com/pingcap/tidb/issues/38825) @[nolouch](https://github.com/nolouch) @[BornChanger](https://github.com/BornChanger) @[glorv](https://github.com/glorv) @[tiancaiamao](https://github.com/tiancaiamao) @[Connor1996](https://github.com/Connor1996) @[JmPotato](https://github.com/JmPotato) @[hnes](https://github.com/hnes) @[CabinfeverB](https://github.com/CabinfeverB) @[HuSharp](https://github.com/HuSharp)
@@ -116,6 +138,18 @@ In v7.1.0, the key new features and improvements are as follows:
 
     For more information, see [documentation](/statistics.md#load-statistics).
 
+* TiCDC supports the integrity validation feature for single-row data [#8718](https://github.com/pingcap/tiflow/issues/8718) [#42747](https://github.com/pingcap/tidb/issues/42747) @[3AceShowHand](https://github.com/3AceShowHand) @[zyguan](https://github.com/zyguan) **tw:Oreoxmt**
+
+    Starting from v7.1.0, TiCDC introduces the data integrity validation feature, which uses a checksum algorithm to validate the integrity of single-row data. This feature helps verify whether any error occurs in the process of writing data from TiDB, replicating it through TiCDC, and then writing it to a Kafka cluster. The data integrity validation feature only supports changefeeds that use Kafka as the downstream and currently supports the Avro protocol.
+
+    For more information, see [documentation](/ticdc/ticdc-integrity-check.md).
+
+* TiCDC optimizes DDL replication operations [#8686](https://github.com/pingcap/tiflow/issues/8686) @[nongfushanquan](https://github.com/nongfushanquan) **tw:ran-huang**
+
+    Before v7.1.0, when you perform a DDL operation that affects all rows on a large table (such as adding or deleting a column), the replication latency of TiCDC would significantly increase. Starting from v7.1.0, TiCDC optimizes this replication operation and mitigates the impact of DDL operations on downstream latency.
+
+    For more information, see [documentation](). (to be added)
+
 ### SQL
 
 * Support saving TiFlash query results using the `INSERT INTO SELECT` statement (GA) [#37515](https://github.com/pingcap/tidb/issues/37515) @[gengliqi](https://github.com/gengliqi)
@@ -195,6 +229,14 @@ In v7.1.0, the key new features and improvements are as follows:
 
     For more information, see [documentation](/ddl-introduction.md#ddl-related-commands).
 
+* Support smooth cluster upgrade without manually canceling DDL operations [#39751](https://github.com/pingcap/tidb/issues/39751) @[zimulala](https://github.com/zimulala) @[hawkingrei](https://github.com/hawkingrei) **tw:ran-huang**
+
+    Before TiDB v7.1.0, to upgrade a cluster, you must manually cancel its running or queued DDL tasks before the upgrade and then add them back after the upgrade.
+
+    To provide a smoother upgrade experience, TiDB v7.1.0 supports automatically pausing and resuming DDL tasks. Starting from v7.1.0, you can upgrade your clusters without manually canceling DDL tasks in advance. TiDB will automatically pause any running or queued DDL tasks before the upgrade and resume these tasks after the rolling upgrade, making it easier for you to upgrade your TiDB clusters.
+
+    For more information, see [documentation](to be added).
+
 ### Observability
 
 * Enhance optimizer diagnostic information [#43122](https://github.com/pingcap/tidb/issues/43122) @[time-and-fate](https://github.com/time-and-fate)