FastScan GA (#12867)

pingcap · Mar 20, 2023 · 8500e23 · 8500e23
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diff --git a/TOC-tidb-cloud.md b/TOC-tidb-cloud.md
@@ -47,7 +47,7 @@
       - [Follower Read](/develop/dev-guide-use-follower-read.md)
       - [Stale Read](/develop/dev-guide-use-stale-read.md)
     - [HTAP Queries](/develop/dev-guide-hybrid-oltp-and-olap-queries.md)
-    - [FastScan](/develop/dev-guide-use-fastscan.md)
+    - [FastScan](/tiflash/use-fastscan.md)
   - Transaction
     - [Overview](/develop/dev-guide-transaction-overview.md)
     - [Optimistic and Pessimistic Transactions](/develop/dev-guide-optimistic-and-pessimistic-transaction.md)

diff --git a/TOC.md b/TOC.md
@@ -51,7 +51,6 @@
       - [Follower Read](/develop/dev-guide-use-follower-read.md)
       - [Stale Read](/develop/dev-guide-use-stale-read.md)
     - [HTAP Queries](/develop/dev-guide-hybrid-oltp-and-olap-queries.md)
-    - [FastScan](/develop/dev-guide-use-fastscan.md)
   - Transaction
     - [Overview](/develop/dev-guide-transaction-overview.md)
     - [Optimistic and Pessimistic Transactions](/develop/dev-guide-optimistic-and-pessimistic-transaction.md)
@@ -588,6 +587,7 @@
     - [Use TiDB to Read TiFlash Replicas](/tiflash/use-tidb-to-read-tiflash.md)
     - [Use TiSpark to Read TiFlash Replicas](/tiflash/use-tispark-to-read-tiflash.md)
     - [Use MPP Mode](/tiflash/use-tiflash-mpp-mode.md)
+    - [Use FastScan](/tiflash/use-fastscan.md)
     - [Supported Push-down Calculations](/tiflash/tiflash-supported-pushdown-calculations.md)
     - [TiFlash Query Result Materialization](/tiflash/tiflash-results-materialization.md)
     - [Data Validation](/tiflash/tiflash-data-validation.md)

diff --git a/basic-features.md b/basic-features.md
@@ -44,22 +44,22 @@ This document lists the features supported in different TiDB versions, including
 
 ## Indexing and constraints
 
-| Indexing and constraints                                    | 6.6 | 6.5 | 6.1 | 5.4          |   5.3    |   5.2    |   5.1    |   5.0    |   4.0    |
-| ------------------------------------------------------------ | :--: | :--: | ------------ | :----------: | :----------: | :----------: | :----------: | :----------: | :----------: |
-| [Expression indexes](/sql-statements/sql-statement-create-index.md#expression-index) [^2] | Y | Y | E | E | E | E | E | E ||
-| [Columnar storage (TiFlash)](/tiflash/tiflash-overview.md)   | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
-| [Use FastScan to accelerate queries in OLAP scenarios](/develop/dev-guide-use-fastscan.md) | E | E | N | N | N | N | N | N | N |
-| [RocksDB engine](/storage-engine/rocksdb-overview.md)        | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
-| [Titan plugin](/storage-engine/titan-overview.md)            | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
-| [Titan Level Merge](/storage-engine/titan-configuration.md#level-merge-experimental)   |  E  |  E   |  E    |    E     |    E     |    E     |    E     |    E     |    E     |
-| [Use buckets to improve scan concurrency](/tune-region-performance.md#use-bucket-to-increase-concurrency) | E | E | E | N | N | N | N | N | N |
-| [Invisible indexes](/sql-statements/sql-statement-add-index.md) | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      N       |
-| [Composite `PRIMARY KEY`](/constraints.md)                   | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
-| [Unique indexes](/constraints.md)                            | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
-| [Clustered index on integer `PRIMARY KEY`](/constraints.md)  | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
-| [Clustered index on composite or non-integer key](/constraints.md) | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      N       |
-| [Multi-valued index](/sql-statements/sql-statement-create-index.md#multi-valued-index) | E | N | N | N | N | N | N | N |
-| [Foreign key](/constraints.md#foreign-key) | Y | N | N | N | N | N | N | N |
+| Indexing and constraints                                    | 7.0 | 6.6 | 6.5 | 6.1 | 5.4          |   5.3    |   5.2    |   5.1    |   5.0    |   4.0    |
+| ------------------------------------------------------------ | :--: | :--: | :--: | ------------ | :----------: | :----------: | :----------: | :----------: | :----------: | :----------: |
+| [Expression indexes](/sql-statements/sql-statement-create-index.md#expression-index) [^2] | Y | Y | Y | E | E | E | E | E | E ||
+| [Columnar storage (TiFlash)](/tiflash/tiflash-overview.md)   | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
+| [Use FastScan to accelerate queries in OLAP scenarios](/tiflash/use-fastscan.md) | Y | E | E | N | N | N | N | N | N | N |
+| [RocksDB engine](/storage-engine/rocksdb-overview.md)        | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
+| [Titan plugin](/storage-engine/titan-overview.md)            | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
+| [Titan Level Merge](/storage-engine/titan-configuration.md#level-merge-experimental)   | E |  E  |  E   |  E    |    E     |    E     |    E     |    E     |    E     |    E     |
+| [Use buckets to improve scan concurrency](/tune-region-performance.md#use-bucket-to-increase-concurrency) | E | E | E | E | N | N | N | N | N | N |
+| [Invisible indexes](/sql-statements/sql-statement-add-index.md) | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      N       |
+| [Composite `PRIMARY KEY`](/constraints.md)                   | Y | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
+| [Unique indexes](/constraints.md)                            | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
+| [Clustered index on integer `PRIMARY KEY`](/constraints.md)  | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      Y       |
+| [Clustered index on composite or non-integer key](/constraints.md) | Y | Y | Y | Y | Y            |      Y       |      Y       |      Y       |      Y       |      N       |
+| [Multi-valued index](/sql-statements/sql-statement-create-index.md#multi-valued-index) | E | E | N | N | N | N | N | N | N |
+| [Foreign key](/constraints.md#foreign-key) | Y | Y | N | N | N | N | N | N | N |
 
 ## SQL statements
 

diff --git a/releases/release-6.2.0.md b/releases/release-6.2.0.md
@@ -137,7 +137,7 @@ In v6.2.0-DMR, the key new features and improvements are as follows:
 
     When you upgrade from an earlier version to TiDB v6.2.0, FastScan is not enabled by default for all tables, which ensures data consistency. You can enable FastScan for each table independently. If the table is set to FastScan in TiDB v6.2.0, it will be disabled when you downgrade to a lower version, but this does not affect the normal data read. In this case, it is equivalent to strong consistency read.
 
-    [User document](/develop/dev-guide-use-fastscan.md) [#5252](https://github.com/pingcap/tiflash/issues/5252) @[hongyunyan](https://github.com/hongyunyan)
+    [User document](/tiflash/use-fastscan.md) [#5252](https://github.com/pingcap/tiflash/issues/5252) @[hongyunyan](https://github.com/hongyunyan)
 
 ### Stability
 

diff --git a/releases/release-6.3.0.md b/releases/release-6.3.0.md
@@ -82,7 +82,7 @@ In v6.3.0-DMR, the key new features and improvements are as follows:
 
 * TiFlash changes the way of using FastScan (experimental) [#5252](https://github.com/pingcap/tiflash/issues/5252) @[hongyunyan](https://github.com/hongyunyan)
 
-    In v6.2.0, TiFlash introduces the FastScan feature, which brings expected performance improvements but lacks flexibility in use. Therefore, in v6.3.0, TiFlash changes [the way of using FastScan](/develop/dev-guide-use-fastscan.md): the `ALTER TABLE ... SET TIFLASH MODE ...` syntax to enable or disable FastScan is deprecated. Instead, you can use the system variable [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630) to easily control whether to enable FastScan.
+    In v6.2.0, TiFlash introduces the FastScan feature, which brings expected performance improvements but lacks flexibility in use. Therefore, in v6.3.0, TiFlash changes [the way of using FastScan](/tiflash/use-fastscan.md): the `ALTER TABLE ... SET TIFLASH MODE ...` syntax to enable or disable FastScan is deprecated. Instead, you can use the system variable [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630) to easily control whether to enable FastScan.
 
     When you upgrade from v6.2.0 to v6.3.0, all FastScan settings in v6.2.0 will become invalid, but will not affect the normal reading of data. You need to set the variable `tiflash_fastscan`. When you upgrade from v6.2.0 or an earlier version to v6.3.0, the FastScan feature is not enabled by default for all sessions to keep data consistency.
 
@@ -230,7 +230,7 @@ In v6.3.0-DMR, the key new features and improvements are as follows:
 | [`tidb_partition_prune_mode`](/system-variables.md#tidb_partition_prune_mode-new-in-v51) | Modified | Specifies whether to enable dynamic pruning. Since v6.3.0, the default value changes to `dynamic`. |
 | [`tidb_rc_read_check_ts`](/system-variables.md#tidb_rc_read_check_ts-new-in-v600) | Modified | Used for optimizing the timestamp acquisition, which is suitable for scenarios with read-committed isolation level where read-write conflicts are rare. This feature is oriented to specific service workloads and might cause performance regression in other scenarios. For this reason, since v6.3.0, the scope of this variable changes from `GLOBAL \| SESSION` to `INSTANCE`. That means you can enable this feature for specific TiDB instances. |
 | [`tidb_rc_write_check_ts`](/system-variables.md#tidb_rc_write_check_ts-new-in-v630)  | Newly added | Used for optimizing the acquisition of timestamps and is suitable for scenarios with few point-write conflicts in RC isolation level of pessimistic transactions. Enabling this variable can avoid the latency and overhead brought by obtaining the global timestamps during the execution of point-write statements |
-| [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630) | Newly added | Controls whether to enable FastScan. If [FastScan](/develop/dev-guide-use-fastscan.md) is enabled (set to `ON`), TiFlash provides more efficient query performance, but does not guarantee the accuracy of the query results or data consistency. |
+| [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630) | Newly added | Controls whether to enable FastScan. If [FastScan](/tiflash/use-fastscan.md) is enabled (set to `ON`), TiFlash provides more efficient query performance, but does not guarantee the accuracy of the query results or data consistency. |
 
 ### Configuration file parameters
 
@@ -255,7 +255,7 @@ In v6.3.0-DMR, the key new features and improvements are as follows:
 
 * Log backup supports GCS and Azure Blob Storage as backup storage.
 * Log backup is now compatible with the `exchange partition` DDL.
-* The SQL statement `ALTER TABLE ...SET TiFLASH MODE ...` previously used for enabling [fastscan](/develop/dev-guide-use-fastscan.md) is deprecated, and replaced by the system variable [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630). When you upgrade from v6.2.0 to v6.3.0, all FastScan settings in v6.2.0 will become invalid, but will not affect the normal reading of data. In this case, you need to configure the variable [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630) to enable or disable FastScan. When you upgrade from an earlier version to v6.3.0, the FastScan feature is not enabled by default for all sessions to keep data consistent.
+* The SQL statement `ALTER TABLE ...SET TiFLASH MODE ...` previously used for enabling [fastscan](/tiflash/use-fastscan.md) is deprecated, and replaced by the system variable [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630). When you upgrade from v6.2.0 to v6.3.0, all FastScan settings in v6.2.0 will become invalid, but will not affect the normal reading of data. In this case, you need to configure the variable [`tiflash_fastscan`](/system-variables.md#tiflash_fastscan-new-in-v630) to enable or disable FastScan. When you upgrade from an earlier version to v6.3.0, the FastScan feature is not enabled by default for all sessions to keep data consistent.
 * To deploy TiFlash under the Linux AMD64 architecture, the CPU must support the AVX2 instruction set. Ensure that `cat /proc/cpuinfo | grep avx2` has output. To deploy TiFlash under the Linux ARM64 architecture, the CPU must support the ARMv8 instruction set architecture. Ensure that `cat /proc/cpuinfo | grep 'crc32' | grep 'asimd'` has output. By using the instruction set extensions, TiFlash's vectorization engine can deliver better performance.
 * The minimum version of HAProxy that works with TiDB is now v1.5. HAProxy versions between v1.5 and v2.1 now require the `post-41` configuration option to be set in `mysql-check`. It is recommended to use HAProxy v2.2 or newer.
 

diff --git a/system-variables.md b/system-variables.md
@@ -4396,7 +4396,7 @@ For details, see [Identify Slow Queries](/identify-slow-queries.md).
 - Scope: SESSION | GLOBAL
 - Default value: `OFF`
 - Type: Boolean
-- If [FastScan](/develop/dev-guide-use-fastscan.md) is enabled (set to `ON`), TiFlash provides more efficient query performance, but does not guarantee the accuracy of the query results or data consistency.
+- If [FastScan](/tiflash/use-fastscan.md) is enabled (set to `ON`), TiFlash provides more efficient query performance, but does not guarantee the accuracy of the query results or data consistency.
 
 ### tiflash_fine_grained_shuffle_batch_size <span class="version-mark">New in v6.2.0</span>
 

diff --git a/tiflash-620-upgrade-guide.md b/tiflash-620-upgrade-guide.md
@@ -14,7 +14,7 @@ To learn the standard upgrade process, see the following documents:
 
 > **Note:**
 >
-> - An experimental feature introduced in v6.2.0, [FastScan](/develop/dev-guide-use-fastscan.md) provides more efficient query performance at the cost of strong data consistency. Note that the form and usage of this feature might change in subsequent versions.
+> - [FastScan](/tiflash/use-fastscan.md) is introduced in v6.2.0 as an experimental feature and becomes generally available (GA) in v7.0.0. It provides more efficient query performance at the cost of strong data consistency.
 >
 > - It is not recommended that you upgrade TiDB that includes TiFlash across major versions, for example, from v4.x to v6.x. Instead, you need to upgrade from v4.x to v5.x first, and then to v6.x.
 >

diff --git a/develop/dev-guide-use-fastscan.md → tiflash/use-fastscan.md b/develop/dev-guide-use-fastscan.md → tiflash/use-fastscan.md
@@ -1,14 +1,10 @@
 ---
-title: FastScan
+title: Use FastScan
 summary: Introduces a way to speed up querying in OLAP scenarios by using FastScan.
-aliases: ['/tidb/dev/sql-statement-set-tiflash-mode']
+aliases: ['/tidb/dev/sql-statement-set-tiflash-mode/','/tidb/dev/dev-guide-use-fastscan/']
 ---
 
-# FastScan
-
-> **Warning:**
->
-> This feature is experimental and its form and usage may change in subsequent versions.
+# Use FastScan
 
 This document describes how to use FastScan to speed up queries in Online Analytical Processing (OLAP) scenarios.