update MD by dispatch event pingcap/docs release-8.1

Author: github-actions

markdown-pages/en/tidb/release-8.1/information-schema/information-schema-tidb-index-usage.md

@@ -101,6 +101,7 @@ The output is as follows:
 
 - The data in the `TIDB_INDEX_USAGE` table might be delayed by up to 5 minutes.
 - After TiDB restarts, the data in the `TIDB_INDEX_USAGE` table is cleared.
+- TiDB records index usage for a table only when the table has valid statistics.
 
 ## Read more
 

markdown-pages/en/tidb/release-8.1/ticdc/ticdc-ddl.md

@@ -118,6 +118,7 @@ Assume that the configuration file of your changefeed is as follows:
 [filter]
 rules = ['test.t*']
 
+[[filter.event-filters]]
 matcher = ["test.t1"] # This filter rule applies only to the t1 table in the test database.
 ignore-event = ["create table", "drop table", "truncate table", "rename table"]
 ```

markdown-pages/en/tidbcloud/master/information-schema/information-schema-tidb-index-usage.md

@@ -101,6 +101,7 @@ The output is as follows:
 
 - The data in the `TIDB_INDEX_USAGE` table might be delayed by up to 5 minutes.
 - After TiDB restarts, the data in the `TIDB_INDEX_USAGE` table is cleared.
+- TiDB records index usage for a table only when the table has valid statistics.
 
 ## Read more
 

markdown-pages/en/tidbcloud/master/tidb-cloud/backup-and-restore-serverless.md

@@ -80,6 +80,15 @@ Create and restore to the new cluster. Note the following:
 
 - User credentials and permissions from the source cluster will not be restored to the new cluster.
 
+### Restore timeout
+
+The restore process typically completes within a few minutes. If the restore takes longer than three hours, it is automatically canceled. The outcome of a canceled restore depends on the destination:
+
+- **In-place restore**: the cluster status changes from **Restoring** to **Available**, and the cluster becomes accessible.
+- **Restore to a new cluster**: the new cluster is deleted and the source cluster remains unchanged.
+
+If the data is corrupted after a canceled restore and cannot be recovered, contact [TiDB Cloud Support](/tidb-cloud/tidb-cloud-support.md) for assistance.
+
 ### Perform the restore
 
 To restore your TiDB Cloud Serverless cluster, follow these steps: