pingcap · hfxsd · Oct 9, 2024 · Oct 9, 2024 · Oct 10, 2024 · Oct 10, 2024
diff --git a/releases/release-7.5.4.md b/releases/release-7.5.4.md
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+---
+title: TiDB 7.5.4 Release Notes
+summary: Learn about the compatibility changes, improvements, and bug fixes in TiDB 7.5.4.
+---
+
+# TiDB 7.5.4 Release Notes
+
+Release date: xxxx, 2024
+
+TiDB version: 7.5.4
+
+Quick access: [Quick start](https://docs.pingcap.com/tidb/v7.5/quick-start-with-tidb) | [Production deployment](https://docs.pingcap.com/tidb/v7.5/production-deployment-using-tiup)
+
+## Compatibility changes **tw@qiancai 1**
+
+- Set a default limit of 2048 for DDL historical tasks retrieved through the [TiDB HTTP API](https://github.com/pingcap/tidb/blob/release-7.5/docs/tidb_http_api.md) to prevent OOM issues caused by excessive historical tasks [#55711](https://github.com/pingcap/tidb/issues/55711) @[joccau](https://github.com/joccau)
+
+## Improvements **tw@hfxsd 6**
+
++ TiDB 
+
+    - (dup): release-8.1.1.md > 改进提升> TiDB - `EXPLAIN` 语句支持应用 `tidb_redact_log`，并进一步优化了日志记录的处理逻辑 [#54565](https://github.com/pingcap/tidb/issues/54565) @[hawkingrei](https://github.com/hawkingrei)
+    - Optimize the query speed of TiDB slow queries [#54630](https://github.com/pingcap/tidb/pull/54630) @[yibin87](https://github.com/yibin87)
+
++ TiKV
+
+    - (dup): release-6.5.11.md > 改进提升> TiKV - 优化存在大量 DELETE 版本时 RocksDB 的 compaction 触发机制，以加快磁盘空间回收 [#17269](https://github.com/tikv/tikv/issues/17269) @[AndreMouche](https://github.com/AndreMouche)
+    - (dup): release-8.3.0.md > 改进提升> TiKV - 减少 peer message channel 的内存使用 [#16229](https://github.com/tikv/tikv/issues/16229) @[Connor1996](https://github.com/Connor1996)
+    - Optimize the jittery access delay when restarting TiKV due to waiting for the log to be applied, improving the stability of TiKV [#15874](https://github.com/tikv/tikv/issues/15874) @[LykxSassinator](https://github.com/LykxSassinator)
+    - Optimize TiKV's `DiskFull` detection to make it compatible with RaftEngine's `spill-dir` configuration, ensuring that this feature works consistently [#17356](https://github.com/tikv/tikv/issues/17356) @[LykxSassinator](https://github.com/LykxSassinator)
+
++ TiFlash
+
+    - (dup): release-6.5.11.md > 改进提升> TiFlash - 优化 `LENGTH()` 和 `ASCII()` 函数执行效率 [#9344](https://github.com/pingcap/tiflash/issues/9344) @[xzhangxian1008](https://github.com/xzhangxian1008)
+    - (dup): release-8.1.0.md > 改进提升> TiFlash - 降低 TiFlash 在开启 TLS 后因更新证书而导致 panic 的概率 [#8535](https://github.com/pingcap/tiflash/issues/8535) @[windtalker](https://github.com/windtalker)
+    - Improve the cancel mechanism of the JOIN operator, so that the JOIN operator can respond to cancel requests in a timely manner [#9430](https://github.com/pingcap/tiflash/issues/9430) @[windtalker](https://github.com/windtalker)
+
++ Tools
+
+    + Backup & Restore (BR)
+
+        - (dup): release-8.1.1.md > 改进提升> Tools> Backup & Restore (BR) - 在 TiKV 下载每个 SST 文件之前，新增对 TiKV 是否有足够磁盘空间的检查；如果空间不足，BR 会终止恢复并返回错误 [#17224](https://github.com/tikv/tikv/issues/17224) @[RidRisR](https://github.com/RidRisR)
+
+    + TiCDC
+
+        - (dup): release-6.5.11.md > 改进提升> Tools> TiCDC - 当下游为 TiDB 且授予 `SUPER` 权限时，TiCDC 支持从下游数据库查询 `ADD INDEX DDL` 的执行状态，以避免某些情况下因重试执行 DDL 语句超时而导致数据同步失败 [#10682](https://github.com/pingcap/tiflow/issues/10682) @[CharlesCheung96](https://github.com/CharlesCheung96)
+
+## Bug fixes
+
++ TiDB **tw@Oreoxmt 5**
+
+    - (dup): release-8.3.0.md > 错误修复> TiDB - 修复表较多的情况下 `FLASHBACK DATABASE` 失败的问题 [#54415](https://github.com/pingcap/tidb/issues/54415) @[lance6716](https://github.com/lance6716)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复可以创建非严格自增的 RANGE 分区表的问题 [#54829](https://github.com/pingcap/tidb/issues/54829) @[Defined2014](https://github.com/Defined2014)
+    - (dup): release-8.3.0.md > 错误修复> TiDB - 修复包含 `UNION` 的查询语句可能返回错误结果的问题 [#52985](https://github.com/pingcap/tidb/issues/52985) @[XuHuaiyu](https://github.com/XuHuaiyu)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复当 SQL 异常中断时，`INDEX_HASH_JOIN` 无法正常退出的问题 [#54688](https://github.com/pingcap/tidb/issues/54688) @[wshwsh12](https://github.com/wshwsh12)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 通过重置 `PipelinedWindow` 的 `Open` 方法中的参数，修复当 `PipelinedWindow` 作为 apply 的子节点使用时，由于重复的打开和关闭操作导致重用之前的参数值而发生的意外错误 [#53600](https://github.com/pingcap/tidb/issues/53600) @[XuHuaiyu](https://github.com/XuHuaiyu)
+    - (dup): release-6.5.10.md > 错误修复> TiDB - 修复 information schema 缓存未命中导致 stale read 查询延迟上升的问题 [#53428](https://github.com/pingcap/tidb/issues/53428) @[crazycs520](https://github.com/crazycs520)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复 `Sort` 算子发生落盘且查询出错后，磁盘文件可能没被删除的问题 [#55061](https://github.com/pingcap/tidb/issues/55061) @[wshwsh12](https://github.com/wshwsh12)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复查询被 kill 之后可能返回错误结果而非报错的问题 [#50089](https://github.com/pingcap/tidb/issues/50089) @[D3Hunter](https://github.com/D3Hunter)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复来自 DM 同步的表超过索引列最大长度 `max-index-length` 时，同步失败的问题 [#55138](https://github.com/pingcap/tidb/issues/55138) @[lance6716](https://github.com/lance6716)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复 `INFORMATION_SCHEMA.STATISTICS` 表中 `SUB_PART` 值为空的问题 [#55812](https://github.com/pingcap/tidb/issues/55812) @[Defined2014](https://github.com/Defined2014)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复 DML 语句中包含嵌套的生成列时报错的问题 [#53967](https://github.com/pingcap/tidb/issues/53967) @[wjhuang2016](https://github.com/wjhuang2016)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复 `mysql.stats_histograms` 表的 `tot_col_size` 列可能为负数的潜在风险 [#55126](https://github.com/pingcap/tidb/issues/55126) @[qw4990](https://github.com/qw4990)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复 `IndexNestedLoopHashJoin` 中存在数据竞争的问题 [#49692](https://github.com/pingcap/tidb/issues/49692) @[solotzg](https://github.com/solotzg)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复由于查询超出 `tidb_mem_quota_query` 设定的内存使用限制，导致终止查询时可能卡住的问题 [#55042](https://github.com/pingcap/tidb/issues/55042) @[yibin87](https://github.com/yibin87)
+    - (dup): release-8.3.0.md > 错误修复> TiDB - 修复 `columnEvaluator` 无法识别输入 chunk 中的列引用，导致执行 SQL 报错 `runtime error: index out of range` 的问题 [#53713](https://github.com/pingcap/tidb/issues/53713) @[AilinKid](https://github.com/AilinKid)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复 `SELECT ... WHERE ... ORDER BY ...` 语句在某些情况下执行效率低的性能问题 [#54969](https://github.com/pingcap/tidb/issues/54969) @[tiancaiamao](https://github.com/tiancaiamao)
+    - (dup): release-6.5.11.md > 错误修复> TiDB - 修复 `StreamAggExec` 中的空 `groupOffset` 可能会导致 panic 的问题 [#53867](https://github.com/pingcap/tidb/issues/53867) @[xzhangxian1008](https://github.com/xzhangxian1008)
+    - Fix the issue that TiDB queries cannot be canceled during cop task construction [#55957](https://github.com/pingcap/tidb/issues/55957) @[yibin87](https://github.com/yibin87)
+    - Fix the issue that an `out of range` error might occur when a small display width is specified for a column of the integer type [#55837](https://github.com/pingcap/tidb/issues/55837) @[windtalker](https://github.com/windtalker)
+    - Fix the issue that `duplicate entry` might occur when adding unique indexes [#56161](https://github.com/pingcap/tidb/issues/56161) @[tangenta](https://github.com/tangenta)
+    - Fix the issue that TiDB panics when importing temporary tables using the `IMPORT INTO` statement [#55970](https://github.com/pingcap/tidb/issues/55970) @[D3Hunter](https://github.com/D3Hunter)
+    - Fix the issue of data index inconsistency caused by retries during index addition [#55808](https://github.com/pingcap/tidb/issues/55808) @[lance6716](https://github.com/lance6716)
+
++ TiKV **tw@qiancai 2**
+
+    - (dup): release-6.5.11.md > 错误修复> TiKV - 修复过期副本处理 Raft 快照时，由于分裂操作过慢并且随后立即删除新副本，可能导致 TiKV panic 的问题 [#17469](https://github.com/tikv/tikv/issues/17469) @[hbisheng](https://github.com/hbisheng)
+    - (dup): release-6.5.11.md > 错误修复> TiKV - 修复删除大表或分区后可能导致的流量控制问题 [#17304](https://github.com/tikv/tikv/issues/17304) @[Connor1996](https://github.com/Connor1996)
+    - (dup): release-8.3.0.md > 错误修复> TiKV - 修复早期版本（早于 v7.1）和之后的版本的 bloom filter 无法兼容的问题 [#17272](https://github.com/tikv/tikv/issues/17272) @[v01dstar](https://github.com/v01dstar)
+    - (dup): release-6.5.11.md > 错误修复> TiKV - 修复当主密钥存储于 KMS (Key Management Service) 时无法轮换主密钥的问题 [#17410](https://github.com/tikv/tikv/issues/17410) @[hhwyt](https://github.com/hhwyt)
+    - Fix the issue that the **Storage async write duration** monitoring metric on the TiKV panel in Grafana is inaccurate [#17579](https://github.com/tikv/tikv/issues/17579) @[overvenus](https://github.com/overvenus)
+    - Fix the issue that when a large number of transactions are queuing for lock release on the same key and the key is frequently updated, excessive pressure on deadlock detection might cause TiKV OOM issues [#17394](https://github.com/tikv/tikv/issues/17394) @[MyonKeminta](https://github.com/MyonKeminta)
+
++ PD **tw@lilin90 3**
+
+    - Fix the issue that PD's Region API cannot be requested when a large number of Regions exist [#55872](https://github.com/pingcap/tidb/issues/55872) @[rleungx](https://github.com/rleungx)
+    - Fix the issue that when using a wrong parameter in `evict-leader-scheduler`, PD does not report errors correctly and some schedulers are unavailable [#8619](https://github.com/tikv/pd/issues/8619) @[rleungx](https://github.com/rleungx)
+    - Fix the issue that data race might occur in the scheduling server when a PD leader is switched in the microservice mode [#8538](https://github.com/tikv/pd/issues/8538) @[lhy1024](https://github.com/lhy1024)
+    - (dup): release-7.1.4.md > 错误修复> PD - 修复资源组 (Resource Group) 客户端中未完全删除的 slot 导致分配 token 低于给定值的问题 [#7346](https://github.com/tikv/pd/issues/7346) @[guo-shaoge](https://github.com/guo-shaoge)
+    - (dup): release-8.1.1.md > 错误修复> PD - 修复 `INFORMATION_SCHEMA.RUNAWAY_WATCHES` 表中时间类型不正确的问题 [#54770](https://github.com/pingcap/tidb/issues/54770) @[HuSharp](https://github.com/HuSharp)
+    - (dup): release-6.5.11.md > 错误修复> PD - 修复设置 `replication.strictly-match-label` 为 `true` 导致 TiFlash 启动失败的问题 [#8480](https://github.com/tikv/pd/issues/8480) @[rleungx](https://github.com/rleungx)
+
++ TiFlash **tw@lilin90 2**
+
+    - (dup): release-8.3.0.md > 错误修复> TiFlash - 修复在存算分离架构下，TiFlash 写节点可能重启失败的问题 [#9282](https://github.com/pingcap/tiflash/issues/9282) @[JaySon-Huang](https://github.com/JaySon-Huang)
+    - (dup): release-6.5.11.md > 错误修复> TiFlash - 修复 TiFlash 与任意 PD 之间发生网络分区（即网络连接断开），可能导致读请求超时报错的问题 [#9243](https://github.com/pingcap/tiflash/issues/9243) @[Lloyd-Pottiger](https://github.com/Lloyd-Pottiger)
+    - (dup): release-6.5.11.md > 错误修复> TiFlash - 修复使用 `CAST()` 函数将字符串转换为带时区或非法字符的日期时间时，结果错误的问题 [#8754](https://github.com/pingcap/tiflash/issues/8754) @[solotzg](https://github.com/solotzg)
+    - (dup): release-8.3.0.md > 错误修复> TiFlash - 修复在存算分离架构下，TiFlash 写节点的读快照可能没有被及时释放的问题 [#9298](https://github.com/pingcap/tiflash/issues/9298) @[JinheLin](https://github.com/JinheLin)
+    - Fix the issue that TiFlash fails to parse the table schema when the table contains Bit-type columns with a default value that contains invalid characters [#9461](https://github.com/pingcap/tiflash/issues/9461) @[Lloyd-Pottiger](https://github.com/Lloyd-Pottiger)
+    - Fix the issue that some queries might report errors when late materialization is enabled [#9472](https://github.com/pingcap/tiflash/issues/9472) @[Lloyd-Pottiger](https://github.com/Lloyd-Pottiger)
+    - Fix the issue that converting a data type to the `DECIMAL` type might lead to wrong query results in some extreme cases [#53892](https://github.com/pingcap/tidb/issues/53892) @[guo-shaoge](https://github.com/guo-shaoge)
+
++ Tools **tw@qiancai 3**
+
+    + Backup & Restore (BR)
+
+        - (dup): release-6.5.11.md > 错误修复> Tools> Backup & Restore (BR) - 修复备份过程中由于 TiKV 没有响应导致备份任务无法结束的问题 [#53480](https://github.com/pingcap/tidb/issues/53480) @[Leavrth](https://github.com/Leavrth)
+        - (dup): release-6.5.11.md > 错误修复> Tools> Backup & Restore (BR) - 修复备份恢复的断点路径在一些外部存储中不兼容的问题 [#55265](https://github.com/pingcap/tidb/issues/55265) @[Leavrth](https://github.com/Leavrth)
+        - (dup): release-6.5.11.md > 错误修复> Tools> Backup & Restore (BR) - 修复当 PITR 日志备份任务失败时，用户停止了该任务后，PD 中与该任务相关的 safepoint 未被正确清除的问题 [#17316](https://github.com/tikv/tikv/issues/17316) @[Leavrth](https://github.com/Leavrth)
+        - (dup): release-6.5.11.md > 错误修复> Tools> Backup & Restore (BR) - 修复开启日志备份时，BR 日志可能打印权限凭证敏感信息的问题 [#55273](https://github.com/pingcap/tidb/issues/55273) @[RidRisR](https://github.com/RidRisR)
+        - Fix the issue that BR integration test cases are unstable, and add a new test case to simulate snapshot or log backup file corruption [#53835](https://github.com/pingcap/tidb/issues/53835) @[Leavrth](https://github.com/Leavrth)
+
+    + TiCDC
+
+        - Fix the issue that the **barrier-ts** monitoring metric for changefeed checkpoints might be inaccurate  [#11553](https://github.com/pingcap/tiflow/issues/11553) @[3AceShowHand](https://github.com/3AceShowHand)
+
+    + TiDB Data Migration (DM)
+
+        - (dup): release-6.5.11.md > 错误修复> Tools> TiDB Data Migration (DM) - 修复当索引长度超过 `max-index-length` 默认值时数据同步中断的问题 [#11459](https://github.com/pingcap/tiflow/issues/11459) @[michaelmdeng](https://github.com/michaelmdeng)
+        - (dup): release-6.5.11.md > 错误修复> Tools> TiDB Data Migration (DM) - 修复 DM 在处理 `ALTER DATABASE` 语句时未设置默认数据库导致同步报错的问题 [#11503](https://github.com/pingcap/tiflow/issues/11503) @[lance6716](https://github.com/lance6716)
+        - Fix the issue that multiple DM-master nodes might simultaneously become leaders, leading to data inconsistency [#11602](https://github.com/pingcap/tiflow/issues/11602) @[GMHDBJD](https://github.com/GMHDBJD)
+
+    + TiDB Lightning
+
+        - (dup): release-6.5.11.md > 错误修复> Tools> TiDB Lightning - 修复使用 TiDB Lightning 导入数据时报事务冲突的问题 [#49826](https://github.com/pingcap/tidb/issues/49826) @[lance6716](https://github.com/lance6716)