add release notes 8.5.6

releases/release-8.5.6.md

@@ -0,0 +1,142 @@
+---
+title: TiDB 8.5.6 Release Notes
+summary: Understand the compatibility changes, improvements, and bug fixes in the TiDB 8.5.6 release.
+---
+
+# TiDB 8.5.6 Release Notes
+
+Release Date: 2026-xx-xx
+
+TiDB Version: 8.5.6
+
+Try it out: [Quick Start](https://docs.pingcap.com/tidb/v8.5/quick-start-with-tidb) | [Production Deployment](https://docs.pingcap.com/tidb/v8.5/production-deployment-using-tiup) | [Download Offline Package](https://pingkai.cn/download#tidb-community)
+
+## Feature Details
+
+### Stability
+
+- The ability to set resource limits for background tasks in Resource Control is now Generally Available (GA) [#56019](https://github.com/pingcap/tidb/issues/56019) @[glorv](https://github.com/glorv) **tw@hfxsd** <!--1933-->
+
+    TiDB Resource Control can identify and lower the priority of background tasks. In some scenarios, even with idle resources, users may want to keep the consumption of background tasks at a very low level. Starting from v8.4.0, you can use the `UTILIZATION_LIMIT` parameter to set the maximum percentage of resources that background tasks under Resource Control can use, controlling the usage of all background tasks on each node below this percentage. This feature allows you to finely control the resource consumption of background tasks, further enhancing cluster stability.
+
+    In v8.5.6, this feature is Generally Available (GA).
+
+    For more information, please refer to the [User Documentation](/tidb-resource-control-background-tasks.md).
+
+### Data Migration
+
+- (dup): release-9.0.0.md > # Data migration * Migrate sync-diff-inspector from `pingcap/tidb-tools` to `pingcap/tiflow` repository [#11672](https://github.com/pingcap/tiflow/issues/11672) @[joechenrh](https://github.com/joechenrh)
+
+## Compatibility Changes
+
+- note [#issue](https://github.com/pingcap/${repo-name}/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+## Improvements
+
++ TiDB
+
+    - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
++ TiKV
+
+    - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
++ PD
+
+    - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - (dup): release-7.5.7.md > Improvements> PD - Reduce unnecessary error logs [#9370](https://github.com/tikv/pd/issues/9370) @[bufferflies](https://github.com/bufferflies)
+
++ TiFlash
+
+    - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
++ Tools
+
+    + Backup & Restore (BR)
+
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiCDC
+
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiDB Data Migration (DM)
+
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiDB Lightning
+
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + Dumpling
+
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiUP
+
+        - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+## Bug Fixes
+
++ TiDB
+
+    - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
++ TiKV
+
+    - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - (dup): release-5.1.4.md > Bug fixes> TiKV - Fix the rare data inconsistency issue when retrying a prewrite request in pessimistic transactions [#11187](https://github.com/tikv/tikv/issues/11187)
+
++ PD
+
+    - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
++ TiFlash
+
+    - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+    - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
++ Tools
+
+    + Backup & Restore (BR)
+
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiCDC
+
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiDB Data Migration (DM)
+
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiDB Lightning
+
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + Dumpling
+
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+
+    + TiUP
+
+        - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})
+        - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id})