<![CDATA[Leighteen]]>

<![CDATA[Leighteen]]>https://blog.youkuaiyun.com/Treeerszh-cnhttps://blog.youkuaiyun.com/<![CDATA[ThreadLocal 内存泄漏：`Entry` 的 key 都用弱引用了，为什么还会泄漏]]>https://blog.youkuaiyun.com/Treeers/article/details/163508770https://blog.youkuaiyun.com/Treeers/article/details/163508770TreeersWed, 05 Aug 2026 16:46:04 +0800<![CDATA[时区的坑：为什么存进数据库的时间，差了 8 小时]]>https://blog.youkuaiyun.com/Treeers/article/details/163508686https://blog.youkuaiyun.com/Treeers/article/details/163508686TreeersWed, 05 Aug 2026 16:43:05 +0800<![CDATA[`try-finally` 里的 `return`：为什么 `finally` 会悄悄改掉返回值、吞掉异常]]>https://blog.youkuaiyun.com/Treeers/article/details/163334848https://blog.youkuaiyun.com/Treeers/article/details/163334848TreeersThu, 30 Jul 2026 14:05:37 +0800<![CDATA[DCL 单例为何要 `volatile`：一次半初始化对象引发的血案]]>https://blog.youkuaiyun.com/Treeers/article/details/163331299https://blog.youkuaiyun.com/Treeers/article/details/163331299TreeersThu, 30 Jul 2026 12:00:10 +0800<![CDATA[`==`、`equals` 和 Integer 缓存：为什么 `128 == 128` 是 false]]>https://blog.youkuaiyun.com/Treeers/article/details/163244291https://blog.youkuaiyun.com/Treeers/article/details/163244291TreeersMon, 27 Jul 2026 15:12:07 +0800<![CDATA[`volatile` 到底保证了什么：可见性、有序性，和它管不到的原子性]]>https://blog.youkuaiyun.com/Treeers/article/details/163244057https://blog.youkuaiyun.com/Treeers/article/details/163244057TreeersMon, 27 Jul 2026 15:04:58 +0800<![CDATA[ORDER BY + LIMIT 的坑：为什么加了 `LIMIT` 结果顺序还乱]]>https://blog.youkuaiyun.com/Treeers/article/details/163101453https://blog.youkuaiyun.com/Treeers/article/details/163101453TreeersSat, 25 Jul 2026 22:32:07 +0800<![CDATA[索引失效大全：记住这一条主线，推导出所有失效场景]]>https://blog.youkuaiyun.com/Treeers/article/details/163135182https://blog.youkuaiyun.com/Treeers/article/details/163135182TreeersSat, 25 Jul 2026 22:30:11 +0800<![CDATA[MySQL 深分页优化：`LIMIT 1000000, 20` 为什么越翻越慢]]>https://blog.youkuaiyun.com/Treeers/article/details/163079211https://blog.youkuaiyun.com/Treeers/article/details/163079211TreeersFri, 24 Jul 2026 10:03:57 +0800<![CDATA[DISTINCT 和 GROUP BY 去重，哪个好？]]>https://blog.youkuaiyun.com/Treeers/article/details/163101302https://blog.youkuaiyun.com/Treeers/article/details/163101302TreeersFri, 24 Jul 2026 09:54:16 +0800<![CDATA[为什么金额不能用 `float` 存：一次精度丢失引发的对账事故]]>https://blog.youkuaiyun.com/Treeers/article/details/163082715https://blog.youkuaiyun.com/Treeers/article/details/163082715TreeersThu, 23 Jul 2026 09:55:23 +0800 【强制】小数类型为 `decimal`，禁止使用 `float` 和 `double`。 > 说明：`float` 和 `double` 在存储的时候，存在精度损失的问题，很可能在值的比较时，得到不正确的结果。如果存储的数据范围超]]><![CDATA[为什么 `!=` 和 `NOT IN` 会让索引失效：从 B+ 树的有序性说起]]>https://blog.youkuaiyun.com/Treeers/article/details/163101358https://blog.youkuaiyun.com/Treeers/article/details/163101358TreeersThu, 23 Jul 2026 09:54:59 +0800`）索引就"失效"了。]]><![CDATA[为什么不要用 `SELECT *`：一条军规背后的底层原理]]>https://blog.youkuaiyun.com/Treeers/article/details/163082655https://blog.youkuaiyun.com/Treeers/article/details/163082655TreeersWed, 22 Jul 2026 09:34:39 +0800<![CDATA[一条 SQL 是怎么走索引的：从 EXPLAIN 读懂执行计划]]>https://blog.youkuaiyun.com/Treeers/article/details/163070811https://blog.youkuaiyun.com/Treeers/article/details/163070811TreeersWed, 22 Jul 2026 09:34:20 +0800<![CDATA[COUNT 到底哪个快：`COUNT(*)` vs `COUNT(1)` vs `COUNT(字段)`]]>https://blog.youkuaiyun.com/Treeers/article/details/163079642https://blog.youkuaiyun.com/Treeers/article/details/163079642TreeersTue, 21 Jul 2026 16:32:43 +0800<![CDATA[MongoDB 基础语法与数据结构：从 BSON 到 CRUD 与查询操作符]]>https://blog.youkuaiyun.com/Treeers/article/details/162975848https://blog.youkuaiyun.com/Treeers/article/details/162975848TreeersTue, 21 Jul 2026 15:34:12 +0800<![CDATA[MongoDB 文档模型设计：从关系型思维到文档型思维的转变]]>https://blog.youkuaiyun.com/Treeers/article/details/162975875https://blog.youkuaiyun.com/Treeers/article/details/162975875TreeersMon, 20 Jul 2026 14:04:51 +0800<![CDATA[MongoDB 安装与环境搭建：Windows / Linux / Docker 三种方式详解]]>https://blog.youkuaiyun.com/Treeers/article/details/162972881https://blog.youkuaiyun.com/Treeers/article/details/162972881TreeersMon, 20 Jul 2026 10:45:07 +0800<![CDATA[@Async 异步任务的五个坑]]>https://blog.youkuaiyun.com/Treeers/article/details/162818944https://blog.youkuaiyun.com/Treeers/article/details/162818944TreeersSun, 12 Jul 2026 22:25:07 +0800<![CDATA[当 @Transactional 不再可靠：批量任务中的编程式事务实践]]>https://blog.youkuaiyun.com/Treeers/article/details/162796140https://blog.youkuaiyun.com/Treeers/article/details/162796140TreeersSat, 11 Jul 2026 21:58:50 +0800