support plan replayer for multi sqls (#10522)

sql-plan-replayer.md

@@ -57,14 +57,55 @@ plan replayer dump explain select * from t;
 
 ```sql
 MySQL [test]> plan replayer dump explain select * from t;
+```
+
+```sql
 +------------------------------------------------------------------+
 | Dump_link                                                        |
 +------------------------------------------------------------------+
-| replayer_single_JOGvpu4t7dssySqJfTtS4A==_1635750890568691080.zip |
+| replayer_JOGvpu4t7dssySqJfTtS4A==_1635750890568691080.zip |
 +------------------------------------------------------------------+
 1 row in set (0.015 sec)
 ```
 
+Alternatively, you can use the session variable [`tidb_last_plan_replayer_token`](/system-variables.md#tidb_last_plan_replayer_token-new-in-v630) to obtain the result of the last `PLAN REPLAYER DUMP` execution.
+
+```sql
+SELECT @@tidb_last_plan_replayer_token;
+```
+
+```sql
++-----------------------------------------------------------+
+| @@tidb_last_plan_replayer_token                           |
++-----------------------------------------------------------+
+| replayer_Fdamsm3C7ZiPJ-LQqgVjkA==_1663304195885090000.zip |
++-----------------------------------------------------------+
+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
+plan replayer dump explain 'sqls.txt';
+```
+
+```sql
+Query OK, 0 rows affected (0.03 sec)
+```
+
+```sql
+SELECT @@tidb_last_plan_replayer_token;
+```
+
+```sql
++-----------------------------------------------------------+
+| @@tidb_last_plan_replayer_token                           |
++-----------------------------------------------------------+
+| replayer_LEDKg8sb-K0u24QesiH8ig==_1663226556509182000.zip |
++-----------------------------------------------------------+
+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:
 
 {{< copyable "shell-regular" >}}
@@ -78,7 +119,7 @@ http://${tidb-server-ip}:${tidb-server-status-port}/plan_replayer/dump/${file_to
 {{< copyable "shell-regular" >}}
 
 ```shell
-curl http://127.0.0.1:10080/plan_replayer/dump/replayer_single_JOGvpu4t7dssySqJfTtS4A==_1635750890568691080.zip > plan_replayer.zip
+curl http://127.0.0.1:10080/plan_replayer/dump/replayer_JOGvpu4t7dssySqJfTtS4A==_1635750890568691080.zip > plan_replayer.zip
 ```
 
 ## Use `PLAN REPLAYER` to import cluster information

system-variables.md

@@ -1990,6 +1990,13 @@ For a system upgraded to v5.0 from an earlier version, if you have not modified
     - The information of transaction fallback from async commit or one-phase commit to two-phase commit.
     - The error encountered.
 
+### `tidb_last_plan_replayer_token` <span class="version-mark">New in v6.3.0</span>
+
+- Scope：SESSION
+- Persists to cluster: 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.
+
 ### tidb_log_file_max_days <span class="version-mark">New in v5.3.0</span>
 
 - Scope: SESSION