partition: global index GA

partitioned-table.md

@@ -1695,10 +1695,6 @@ Before the introduction of global indexes, TiDB created a local index for each p
 
 To address these issues, TiDB introduces the global indexes feature in v8.3.0. A global index covers the data of the entire table with a single index, allowing primary keys and unique keys to maintain global uniqueness without including all partition keys. Moreover, global indexes can access data across multiple partitions in a single operation, significantly improving query performance for non-partitioned keys.
 
-> **Warning:**
->
-> The global indexes feature is experimental. It is not recommended that you use it in the production environment. This feature might be changed or removed without prior notice. If you find a bug, you can report an [issue](https://github.com/pingcap/tidb/issues) on GitHub.
-
 To create a global index for a primary key or unique key that **does not include all the columns used in the partition expressions**, you can enable the [`tidb_enable_global_index`](/system-variables.md#tidb_enable_global_index-new-in-v760) system variable and add the `GLOBAL` keyword in the index definition. 
 
 > **Note:**
@@ -1789,6 +1785,7 @@ ALTER TABLE t1 PARTITION BY HASH (col1) PARTITIONS 3 UPDATE INDEXES (uidx12 LOCA
 - The `GLOBAL` and `LOCAL` keywords only apply to partitioned tables and do not affect non-partitioned tables. In other words, there is no difference between a global index and a local index in non-partitioned tables.
 - DDL operations such as `ADD PARTITION`, `DROP PARTITION`, `TRUNCATE PARTITION`, `REORGANIZE PARTITION`, `SPLIT PARTITION`, and `EXCHANGE PARTITION` also trigger updates to global indexes. The results of these DDL operations will only be returned after the global indexes of the corresponding tables are fully updated. This can delay operations that usually require quick DDL completion, such as data archiving operations (`EXCHANGE PARTITION`, `TRUNCATE PARTITION`, and `DROP PARTITION`). In contrast, when global indexes are not involved, these DDL operations can be completed immediately.
 - By default, the primary key of a partitioned table is a clustered index and must include the partition key. If you require the primary key to exclude the partition key, you can explicitly specify the primary key as a non-clustered global index when creating the table, for example, `PRIMARY KEY(col1, col2) NONCLUSTERED GLOBAL`.
+- If a global index is added to an expression column, or a global index is also a prefix index (for example `UNIQUE KEY idx_id_prefix (id(10)) GLOBAL`), you need to collect statistics manually for that global index.
 
 ### Partitioning limitations relating to functions
 

system-variables.md

@@ -2147,10 +2147,6 @@ mysql> SELECT job_info FROM mysql.analyze_jobs ORDER BY end_time DESC LIMIT 1;
 
 ### tidb_enable_global_index <span class="version-mark">New in v7.6.0</span>
 
-> **Warning:**
->
-> The feature controlled by this variable is experimental. It is not recommended that you use it in the production environment. This feature might be changed or removed without prior notice. If you find a bug, you can report an [issue](https://github.com/pingcap/tidb/issues) on GitHub.
-
 - Scope: SESSION | GLOBAL
 - Persists to cluster: Yes
 - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No