add release notes for v6.5.5 (#14846)

TOC.md

@@ -1001,6 +1001,7 @@
   - v6.6
     - [6.6.0-DMR](/releases/release-6.6.0.md)
   - v6.5
+    - [6.5.5](/releases/release-6.5.5.md)
     - [6.5.4](/releases/release-6.5.4.md)
     - [6.5.3](/releases/release-6.5.3.md)
     - [6.5.2](/releases/release-6.5.2.md)

releases/release-6.5.4.md

@@ -17,17 +17,18 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v6.5/quick-start-with-
 
 ## Improvements
 
-+ TiDB 
++ TiDB
 
     - Optimize the performance of `LOAD DATA` statements that contain assignment expressions [#46081](https://github.com/pingcap/tidb/issues/46081) @[gengliqi](https://github.com/gengliqi)
     - Optimize the performance of reading the dumped chunks from disk [#45125](https://github.com/pingcap/tidb/issues/45125) @[YangKeao](https://github.com/YangKeao)
     - Add a `halt-scheduling` configuration item to suspend PD scheduling [#6493](https://github.com/tikv/pd/issues/6493) @[JmPotato](https://github.com/JmPotato)
-    
+
 + TiKV
 
     - Use gzip compression for `check_leader` requests to reduce traffic [#14553](https://github.com/tikv/tikv/issues/14553) @[you06](https://github.com/you06)
     - Add the `Max gap of safe-ts` and `Min safe ts region` metrics and introduce the `tikv-ctl get_region_read_progress` command to better observe and diagnose the status of resolved-ts and safe-ts [#15082](https://github.com/tikv/tikv/issues/15082) @[ekexium](https://github.com/ekexium)
     - Expose some RocksDB configurations in TiKV that allow users to disable features such as TTL and periodic compaction [#14873](https://github.com/tikv/tikv/issues/14873) @[LykxSassinator](https://github.com/LykxSassinator)
+    - Avoid holding mutex when writing Titan manifest files to prevent affecting other threads [#15351](https://github.com/tikv/tikv/issues/15351) @[Connor1996](https://github.com/Connor1996)
 
 + PD 
 

releases/release-6.5.5.md

@@ -0,0 +1,79 @@
+---
+title: TiDB 6.5.5 Release Notes
+summary: Learn about the improvements and bug fixes in TiDB 6.5.5.
+---
+
+# TiDB 6.5.5 Release Notes
+
+Release date: September 21, 2023
+
+TiDB version: 6.5.5
+
+Quick access: [Quick start](https://docs.pingcap.com/tidb/v6.5/quick-start-with-tidb) | [Production deployment](https://docs.pingcap.com/tidb/v6.5/production-deployment-using-tiup) | [Installation packages](https://www.pingcap.com/download/?version=v6.5.5#version-list)
+
+## Improvements
+
++ TiDB
+
+    - Add new optimizer hints, including [`NO_MERGE_JOIN()`](https://docs.pingcap.com/tidb/v6.5/optimizer-hints#no_merge_joint1_name--tl_name-), [`NO_INDEX_JOIN()`](https://docs.pingcap.com/tidb/v6.5/optimizer-hints#no_index_joint1_name--tl_name-), [`NO_INDEX_MERGE_JOIN()`](https://docs.pingcap.com/tidb/v6.5/optimizer-hints#no_index_merge_joint1_name--tl_name-), [`NO_HASH_JOIN()`](https://docs.pingcap.com/tidb/v6.5/optimizer-hints#no_hash_joint1_name--tl_name-), and [`NO_INDEX_HASH_JOIN()`](https://docs.pingcap.com/tidb/v6.5/optimizer-hints#no_index_hash_joint1_name--tl_name-) [#45520](https://github.com/pingcap/tidb/issues/45520) @[qw4990](https://github.com/qw4990)
+    - Add request source information related to the coprocessor [#46514](https://github.com/pingcap/tidb/issues/46514) @[you06](https://github.com/you06)
+
++ TiKV
+
+    - Add the backoff mechanism for the PD client in the process of connection retries, which gradually increases retry intervals during error retries to reduce PD pressure [#15428](https://github.com/tikv/tikv/issues/15428) @[nolouch](https://github.com/nolouch)
+    - Add monitoring metrics for snapshots [#15401](https://github.com/tikv/tikv/issues/15401) @[SpadeA-Tang](https://github.com/SpadeA-Tang)
+    - Improve stability of PITR checkpoint lag during leader transfers [#13638](https://github.com/tikv/tikv/issues/13638) @[YuJuncen](https://github.com/YuJuncen)
+    - Add logs and monitoring metrics related to `safe-ts` [#15082](https://github.com/tikv/tikv/issues/15082) @[ekexium](https://github.com/ekexium)
+    - Provide more logs and monitoring metrics for `resolved-ts` [#15082](https://github.com/tikv/tikv/issues/15082) @[ekexium](https://github.com/ekexium)
+    - Optimize the compaction mechanism: when a Region is split, if there is no key to split, a compaction is triggered to eliminate excessive MVCC versions [#15282](https://github.com/tikv/tikv/issues/15282) @[SpadeA-Tang](https://github.com/SpadeA-Tang)
+
++ Tools
+
+    + Backup & Restore (BR)
+
+        - Reduce the CPU overhead of log backup `resolve lock` [#40759](https://github.com/pingcap/tidb/issues/40759) @[3pointer](https://github.com/3pointer)
+
+## Bug fixes
+
++ TiDB
+
+    - Fix the issue that Stale Read might select an unavailable replica [#46198](https://github.com/pingcap/tidb/issues/46198) @[zyguan](https://github.com/zyguan)
+    - Fix the issue that additional overhead is incurred due to the incompatibility between Stale Read and Schema Cache [#43481](https://github.com/pingcap/tidb/issues/43481) @[crazycs520](https://github.com/crazycs520)
+
++ TiKV
+
+    - Fix the issue that the peers of the corresponding Region mistakenly hibernate when a TiKV node fails [#14547](https://github.com/tikv/tikv/issues/14547) @[hicqu](https://github.com/hicqu)
+    - Fix the issue that TiKV fails to start when Titan is enabled and the `Blob file deleted twice` error occurs [#15454](https://github.com/tikv/tikv/issues/15454) @[Connor1996](https://github.com/Connor1996)
+    - Fix the issue that Online Unsafe Recovery cannot handle merge abort [#15580](https://github.com/tikv/tikv/issues/15580) @[v01dstar](https://github.com/v01dstar)
+    - Fix the issue that network interruption between PD and TiKV might cause PITR to get stuck [#15279](https://github.com/tikv/tikv/issues/15279) @[YuJuncen](https://github.com/YuJuncen)
+
++ PD
+
+    - Fix the issue that the scheduler takes a long time to start up [#6920](https://github.com/tikv/pd/issues/6920) @[HuSharp](https://github.com/HuSharp)
+    - Fix the issue that the logic for handling Leaders and Peers in Scatter Region is inconsistent [#6962](https://github.com/tikv/pd/issues/6962) @[bufferflies](https://github.com/bufferflies)
+    - Fix the issue that the `empty-region-count` monitoring metric is abnormal when the cluster is restarted or the PD Leader is switched [#7008](https://github.com/tikv/pd/issues/7008) @[CabinfeverB](https://github.com/CabinfeverB)
+
++ Tools
+
+    + Backup & Restore (BR)
+
+        - Fix the issue that restoring implicit primary keys by PITR might lead to conflicts [#46520](https://github.com/pingcap/tidb/issues/46520) @[3pointer](https://github.com/3pointer)
+        - Fix the issue that an error occurs when PITR recovers the meta-kv [#46578](https://github.com/pingcap/tidb/issues/46578) @[Leavrth](https://github.com/Leavrth)
+        - Fix an error in BR integration test cases [#45561](https://github.com/pingcap/tidb/issues/46561) @[purelind](https://github.com/purelind)
+        - Alleviate the issue that the latency of the PITR log backup progress increases when Region leadership migration occurs [#13638](https://github.com/tikv/tikv/issues/13638) @[YuJuncen](https://github.com/YuJuncen)
+
+    + TiCDC
+
+        - Fix the issue of high TiCDC replication latency caused by network isolation of PD nodes [#9565](https://github.com/pingcap/tiflow/issues/9565) @[asddongmen](https://github.com/asddongmen)
+        - Fix the issue that TiCDC incorrectly changes the `UPDATE` operation to `INSERT` when using the CSV format [#9658](https://github.com/pingcap/tiflow/issues/9658) @[3AceShowHand](https://github.com/3AceShowHand)
+        - Fix the issue that user passwords are recorded in some logs [#9690](https://github.com/pingcap/tiflow/issues/9690) @[sdojjy](https://github.com/sdojjy)
+        - Fix the issue that using the SASL authentication might cause TiCDC to panic [#9669](https://github.com/pingcap/tiflow/issues/9669) @[sdojjy](https://github.com/sdojjy)
+        - Fix the issue that TiCDC replication tasks might fail in some corner cases [#9685](https://github.com/pingcap/tiflow/issues/9685) [#9697](https://github.com/pingcap/tiflow/issues/9697) [#9695](https://github.com/pingcap/tiflow/issues/9695) [#9736](https://github.com/pingcap/tiflow/issues/9736) @[hicqu](https://github.com/hicqu) @[CharlesCheung96](https://github.com/CharlesCheung96)
+        - Fix the issue that TiCDC cannot recover quickly from TiKV node failures when there are a lot of Regions upstream [#9741](https://github.com/pingcap/tiflow/issues/9741) @[sdojjy](https://github.com/sdojjy)
+
+    + TiDB Lightning
+
+        - Fix the issue that TiDB Lightning fails to start when TiCDC is deployed on the target server [#41040](https://github.com/pingcap/tidb/issues/41040) @[lance6716](https://github.com/lance6716)
+        - Fix the issue that TiDB Lightning fails to start when PD topology is changed [#46688](https://github.com/pingcap/tidb/issues/46688) @[lance6716](https://github.com/lance6716)
+        - Fix the issue that TiDB Lightning cannot continue importing data after PD switching Leaders [#46540](https://github.com/pingcap/tidb/issues/46540) @[lance6716](https://github.com/lance6716)
+        - Fix the issue that precheck cannot accurately detect the presence of a running TiCDC in the target cluster [#41040](https://github.com/pingcap/tidb/issues/41040) @[lance6716](https://github.com/lance6716)

releases/release-notes.md

@@ -19,6 +19,7 @@ title: Release Notes
 
 ## 6.5
 
+- [6.5.5](/releases/release-6.5.5.md): 2023-09-21
 - [6.5.4](/releases/release-6.5.4.md): 2023-08-28
 - [6.5.3](/releases/release-6.5.3.md): 2023-06-14
 - [6.5.2](/releases/release-6.5.2.md): 2023-04-21

releases/release-timeline.md

@@ -9,6 +9,7 @@ This document shows all the released TiDB versions in reverse chronological orde
 
 | Version | Release Date |
 | :--- | :--- |
+| [6.5.5](/releases/release-6.5.5.md) | 2023-09-21 |
 | [6.5.4](/releases/release-6.5.4.md) | 2023-08-28 |
 | [7.1.1](/releases/release-7.1.1.md) | 2023-07-24 |
 | [6.1.7](/releases/release-6.1.7.md) | 2023-07-12 |