[Doc] Update Migration Tool Preparations

docs/en/administration/data_migration_tool.md

@@ -77,6 +77,14 @@ After the data migration is completed, you need to remove the configuration `lak
 ADMIN SET FRONTEND CONFIG("lake_compaction_max_tasks"="-1");
 ```
 
+### Disable column filtering
+
+The optimization for unused column filtering at the Scan stage may cause a crash during queries against the migrated data. You need to disable this optimization before data migration:
+
+```SQL
+SET GLOBAL enable_filter_unused_columns_in_scan_stage=false;
+```
+
 ### Configure Data Migration (Optional)
 
 You can configure data migration operations using the following FE and BE parameters. In most cases, the default configuration can meet your needs. If you wish to use the default configuration, you can skip this step.

docs/zh/administration/data_migration_tool.md

@@ -77,6 +77,14 @@ ADMIN SET FRONTEND CONFIG("enable_legacy_compatibility_for_replication"="false")
 ADMIN SET FRONTEND CONFIG("lake_compaction_max_tasks"="-1");
 ```
 
+### 禁用列过滤
+
+在 SCAN 阶段过滤未使用列的优化可能会导致查询被迁移的数据时发生崩溃，因此您需要在数据迁移前禁用此优化：
+
+```SQL
+SET GLOBAL enable_filter_unused_columns_in_scan_stage=false;
+```
+
 ### 配置数据迁移（可选）
 
 您可以通过以下 FE 和 BE 参数配置数据迁移操作。通常情况下，默认配置即可满足需求。如果您想保留默认配置，可以选择跳过该步骤。