From c3ab93933fa0a91e6b61578beaf67da5492f15b9 Mon Sep 17 00:00:00 2001
From: Jianjun Liao <jianjun.liao@outlook.com>
Date: Tue, 21 Jan 2025 14:16:14 +0800
Subject: [PATCH 1/2] add unrecoverable system tables list

Signed-off-by: Jianjun Liao <jianjun.liao@outlook.com>
---
 br/br-system-tables.md | 60 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 br/br-system-tables.md

diff --git a/br/br-system-tables.md b/br/br-system-tables.md
new file mode 100644
index 000000000000..a5a05935efa5
--- /dev/null
+++ b/br/br-system-tables.md
@@ -0,0 +1,60 @@
+---
+title: 快照恢复时无法恢复的系统表
+summary: 列出快照恢复时无法恢复的系统表
+---
+
+# 快照恢复时无法恢复的系统表
+
+在使用快照备份来备份集群时，BR 会将系统表备份为库名带 `__TiDB_BR_Temporary_` 前缀的表，例如表 `mysql.user` 将会被备份为 `__TiDB_BR_Temporary_mysql.user`. 因此在进行快照恢复时会首先恢复一系列库名带 `__TiDB_BR_Temporary_` 前缀的系统表，避免与恢复集群现有的系统表中的数据冲突。当 BR 开始恢复系统表时，会通过 `REPLACE INTO` 的 SQL 将数据从库名带 `__TiDB_BR_Temporary_` 前缀的表写入到对应的系统表中。
+
+下面列出了快照恢复无法通过上述方式进行恢复的系统表。
+
+* `mysql`
+    * `advisory_locks` 
+    * `analyze_jobs`
+    * `analyze_options`
+    * `capture_plan_baselines_blacklist`
+    * `column_stats_usage`
+    * `dist_framework_meta`
+    * `gc_delete_range`
+    * `gc_delete_range_done`
+    * `global_variables`
+    * `help_topic`
+    * `index_advisor_results`
+    * `plan_replayer_status`
+    * `plan_replayer_task`
+    * `request_unit_by_group`
+    * `stats_buckets`
+    * `stats_extended`
+	* `stats_feedback`
+	* `stats_fm_sketch`
+	* `stats_histograms`
+	* `stats_history`
+	* `stats_meta`
+	* `stats_meta_history`
+	* `stats_table_locked`
+	* `stats_top_n`
+    * `table_cache_meta`
+    * `tidb`
+    * `tidb_background_subtask`
+    * `tidb_background_subtask_history`
+    * `tidb_ddl_history`
+    * `tidb_ddl_job`
+    * `tidb_ddl_notifier`
+    * `tidb_ddl_reorg`
+    * `tidb_global_task`
+    * `tidb_global_task_history`
+    * `tidb_import_jobs`
+    * `tidb_mdl_info`
+    * `tidb_mdl_view`
+    * `tidb_pitr_id_map`
+    * `tidb_runaway_queries`
+    * `tidb_runaway_watch`
+    * `tidb_runaway_watch_done`
+    * `tidb_timers`
+    * `tidb_ttl_job_history`
+    * `tidb_ttl_table_status`
+    * `tidb_ttl_task`
+
+* `sys`
+    * `schema_unused_indexes`

From 3205b5ffc7e0e9d4171d07a3031e947c6118d3dd Mon Sep 17 00:00:00 2001
From: Jianjun Liao <jianjun.liao@outlook.com>
Date: Tue, 21 Jan 2025 14:32:01 +0800
Subject: [PATCH 2/2] fix typos

Signed-off-by: Jianjun Liao <jianjun.liao@outlook.com>
---
 br/br-system-tables.md | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/br/br-system-tables.md b/br/br-system-tables.md
index a5a05935efa5..13fd3aea7021 100644
--- a/br/br-system-tables.md
+++ b/br/br-system-tables.md
@@ -26,14 +26,14 @@ summary: 列出快照恢复时无法恢复的系统表
     * `request_unit_by_group`
     * `stats_buckets`
     * `stats_extended`
-	* `stats_feedback`
-	* `stats_fm_sketch`
-	* `stats_histograms`
-	* `stats_history`
-	* `stats_meta`
-	* `stats_meta_history`
-	* `stats_table_locked`
-	* `stats_top_n`
+    * `stats_feedback`
+    * `stats_fm_sketch`
+    * `stats_histograms`
+    * `stats_history`
+    * `stats_meta`
+    * `stats_meta_history`
+    * `stats_table_locked`
+    * `stats_top_n`
     * `table_cache_meta`
     * `tidb`
     * `tidb_background_subtask`