docs: update PLAN REPLAYER object storage behavior

sql-plan-replayer.md

@@ -20,6 +20,8 @@ You can use `PLAN REPLAYER` to save the on-site information of a TiDB cluster. T
 PLAN REPLAYER DUMP [WITH STATS AS OF TIMESTAMP expression] EXPLAIN [ANALYZE] sql-statement;
 ```
 
+By default, TiDB stores files generated by `PLAN REPLAYER` in local storage. If you set [`tidb_plan_replayer_external_storage_uri`](/system-variables.md#tidb_plan_replayer_external_storage_uri-new-in-v900) to a valid external storage URI, TiDB stores the generated `ZIP` files in the specified location. The configured URI must point to a storage path with the required read, write, and delete permissions. For supported URI formats, see [URI Formats of External Storage Services](/external-storage-uri.md).
+
 Based on `sql-statement`, TiDB sorts out and exports the following on-site information:
 
 - TiDB version
@@ -54,11 +56,14 @@ plan replayer dump with stats as of timestamp '2023-07-17 12:00:00' explain sele
 plan replayer dump with stats as of timestamp '442012134592479233' explain select * from t;
 ```
 
-`PLAN REPLAYER DUMP` packages the table information above into a `ZIP` file and returns the file identifier as the execution result.
+`PLAN REPLAYER DUMP` packages the table information above into a `ZIP` file and returns the download information as the execution result:
+
+- If the configured storage backend supports presigned URLs, TiDB returns a presigned URL.
+- Otherwise, TiDB returns a file token.
 
 > **Note:**
 >
-> The `ZIP` file is stored in a TiDB cluster for at most one hour. After one hour, TiDB will delete it.
+> The result file is kept for at most one hour. After one hour, TiDB deletes it from the corresponding local or external storage.
 
 ```sql
 MySQL [test]> plan replayer dump explain select * from t;
@@ -88,6 +93,17 @@ SELECT @@tidb_last_plan_replayer_token;
 1 row in set (0.00 sec)
 ```
 
+If the configured storage backend supports presigned URLs, the result returned by `PLAN REPLAYER DUMP` or `tidb_last_plan_replayer_token` is a presigned URL instead of a file token. For example:
+
+```sql
++----------------------------------------------------------------------------------------------------------------------+
+| Dump_link                                                                                                            |
++----------------------------------------------------------------------------------------------------------------------+
+| https://storage.example.com/replayer_xxx.zip?X-Amz-Algorithm=...&X-Amz-Credential=...&X-Amz-Signature=...          |
++----------------------------------------------------------------------------------------------------------------------+
+1 row in set (0.00 sec)
+```
+
 When there are multiple SQL statements, you can obtain the result of the `PLAN REPLAYER DUMP` execution using a file. The results of multiple SQL statements are separated by `;` in this file.
 
 ```sql
@@ -111,7 +127,15 @@ SELECT @@tidb_last_plan_replayer_token;
 1 row in set (0.00 sec)
 ```
 
-Because the file cannot be downloaded on MySQL Client, you need to use the TiDB HTTP interface and the file identifier to download the file:
+If `PLAN REPLAYER DUMP` returns a presigned URL, you can use the URL directly to download the file. The presigned URL is valid for up to one hour.
+
+{{< copyable "shell-regular" >}}
+
+```shell
+curl "${presigned_url}" > plan_replayer.zip
+```
+
+If `PLAN REPLAYER DUMP` returns a file token, you need to use the TiDB HTTP interface and the file token to download the file:
 
 {{< copyable "shell-regular" >}}
 
@@ -261,11 +285,13 @@ mysql> SELECT * FROM mysql.plan_replayer_status;
 3 rows in set (0.00 sec)
 ```
 
-The method of downloading the file of `PLAN REPLAYER CAPTURE` is the same as that of `PLAN REPLAYER`. For details, see [Examples of exporting cluster information](#examples-of-exporting-cluster-information).
+If [`tidb_plan_replayer_external_storage_uri`](/system-variables.md#tidb_plan_replayer_external_storage_uri-new-in-v900) is configured, TiDB also stores captured files in the specified external storage. The `token` column in the `mysql.plan_replayer_status` table records the file token of each captured file.
+
+To download a file generated by `PLAN REPLAYER CAPTURE`, use the value in the `token` column together with the TiDB HTTP interface. This process is the same as the file token-based download flow described in [Examples of exporting cluster information](#examples-of-exporting-cluster-information).
 
 > **Note:**
 >
-> The result file of `PLAN REPLAYER CAPTURE` is kept in the TiDB cluster for up to one week. After one week, TiDB deletes the file.
+> The result file of `PLAN REPLAYER CAPTURE` is kept for up to one week. After one week, TiDB deletes it from the corresponding local or external storage.
 
 ### Remove the capture tasks
 

system-variable-reference.md

@@ -3391,6 +3391,14 @@ Referenced in:
 - [System Variables](/system-variables.md#tidb_plan_cache_max_plan_size-new-in-v710)
 - [TiDB 7.1.0 Release Notes](/releases/release-7.1.0.md)
 
+
+### tidb_plan_replayer_external_storage_uri
+
+Referenced in:
+
+- [System Variables](/system-variables.md#tidb_plan_replayer_external_storage_uri-new-in-v900)
+- [Use PLAN REPLAYER to Save and Restore the On-Site Information of a Cluster](/sql-plan-replayer.md)
+
 ### tidb_pprof_sql_cpu
 
 Referenced in:

system-variables.md

@@ -3701,7 +3701,7 @@ For a system upgraded to v5.0 from an earlier version, if you have not modified
 - Scope: SESSION
 - Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No
 - Type: String
-- This variable is read-only and is used to obtain the result of the last `PLAN REPLAYER DUMP` execution in the current session.
+- This variable is read-only and is used to obtain the result of the last `PLAN REPLAYER DUMP` execution in the current session. The result is either a file token or, if the configured storage backend supports it, a presigned URL.
 
 ### tidb_load_based_replica_read_threshold <span class="version-mark">New in v7.0.0</span>
 
@@ -5367,6 +5367,20 @@ SHOW WARNINGS;
 - Range: `[0, 9223372036854775807]`, in bytes. The memory format with the units "KiB|MiB|GiB|TiB" is also supported. `0` means no limit.
 - This variable controls the maximum size of a plan that can be cached in prepared or non-prepared plan cache. If the size of a plan exceeds this value, the plan will not be cached. For more details, see [Memory management of prepared plan cache](/sql-prepared-plan-cache.md#memory-management-of-prepared-plan-cache) and [Non-prepared plan cache](/sql-plan-management.md#usage).
 
+
+### tidb_plan_replayer_external_storage_uri <span class="version-mark">New in v9.0.0</span>
+
+- Scope: GLOBAL
+- Persists to cluster: Yes
+- Applies to hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value): No
+- Type: String
+- Default value: `""`
+- This variable is used to specify the external storage URI for files generated by [`PLAN REPLAYER`](/sql-plan-replayer.md). If this variable is empty, `PLAN REPLAYER` uses local storage. The configured URI must point to a storage path with the required read, write, and delete permissions. For supported URI formats, see [URI Formats of External Storage Services](/external-storage-uri.md).
+- The following statements and features use this variable:
+    - [`PLAN REPLAYER DUMP`](/sql-plan-replayer.md)
+    - [`PLAN REPLAYER CAPTURE`](/sql-plan-replayer.md)
+    - [`PLAN REPLAYER CONTINUOUS CAPTURE`](/sql-plan-replayer.md)
+
 ### tidb_pprof_sql_cpu <span class="version-mark">New in v4.0</span>
 
 > **Note:**