Merge branch 'v8.4.0/release-notes' into remove-comments-in-release-n…

…otes

releases/release-8.4.0.md

@@ -154,7 +154,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.4/quick-start-with-
 
 * Support switching resource groups for runaway queries [#54434](https://github.com/pingcap/tidb/issues/54434) @[JmPotato](https://github.com/JmPotato)
 
-    Starting from TiDB v8.4.0, you can switch the resource group of runaway queries to a specific one. If the `COOLDOWN` mechanism fails to lower resource consumption, you can create a [resource group](/tidb-resource-control.md#create-a-resource-group) and set the `SWITCH_GROUP` parameter to move identified runaway queries to this group. Meanwhile, subsequent queries within the same session will continue to execute in the original resource group. By switching resource groups, you can manage resource usage more precisely, and control the resource consumption more strictly.
+    Starting from TiDB v8.4.0, you can switch the resource group of runaway queries to a specific one. If the `COOLDOWN` mechanism fails to lower resource consumption, you can create a [resource group](/tidb-resource-control.md#create-a-resource-group), limit its resource size, and set the `SWITCH_GROUP` parameter to move identified runaway queries to this group. Meanwhile, subsequent queries within the same session will continue to execute in the original resource group. By switching resource groups, you can manage resource usage more precisely, and control the resource consumption more strictly.
 
     For more information, see [documentation](/tidb-resource-control.md#query_limit-parameters).
 
@@ -362,7 +362,7 @@ Starting from v8.4.0, the following contents are removed from the `TiDB-communit
 + TiDB
 
     - Optimize the efficiency of constructing BatchCop tasks when scanning a large amount of data [#55915](https://github.com/pingcap/tidb/issues/55915) [#55413](https://github.com/pingcap/tidb/issues/55413) @[wshwsh12](https://github.com/wshwsh12)
-    - Optimize MEMDB implementation to reduce write latency in transactions and TiDB CPU usage [#55287](https://github.com/pingcap/tidb/issues/55287) @[you06](https://github.com/you06)
+    - Optimize the transaction's buffer to reduce write latency in transactions and TiDB CPU usage [#55287](https://github.com/pingcap/tidb/issues/55287) @[you06](https://github.com/you06)
     - Optimize the execution performance of DML statements when the system variable `tidb_dml_type` is set to `"bulk"` [#50215](https://github.com/pingcap/tidb/issues/50215) @[ekexium](https://github.com/ekexium)
     - Support using [Optimizer Fix Control 47400](/optimizer-fix-controls.md#47400-new-in-v840) to control whether the optimizer limits the minimum value estimated for `estRows` to `1`, which is consistent with databases such as Oracle and DB2 [#47400](https://github.com/pingcap/tidb/issues/47400) @[terry1purcell](https://github.com/terry1purcell)
     - Add write control to the [`mysql.tidb_runaway_queries`](/mysql-schema/mysql-schema.md#system-tables-related-to-runaway-queries) log table to reduce overhead caused by a large number of concurrent writes [#54434](https://github.com/pingcap/tidb/issues/54434) @[HuSharp](https://github.com/HuSharp)