Tencent's Database R&D team supports internal services such as WeChat Pay, WeChat Red Packets, Tencent Advertising, and Tencent Music, and provides external support on Tencent Cloud for TencentDB products like CynosDB, CDB, and TDSQL. This public account aims to promote and share professional database knowledge, growing together with database enthusiasts.
The article explains why a C++ program produces different outputs with and without the -O2 optimization flag, tracing the issue to strict aliasing violations caused by type‑punning pointer casts, and shows how disabling -fstrict-aliasing or using -fno‑strict‑aliasing resolves the problem.
This article analyzes intermittent IO write spikes in a MySQL slave instance, tracing them to concurrent InnoDB tablespace extensions triggered by large BLOB inserts across thousands of tables, and proposes mitigation strategies.
The article analyzes why MySQL tables upgraded from 5.6 to 5.7 began generating duplicate‑key errors during inserts, examines related InnoDB auto‑increment mechanisms, reproduces the issue, discusses known bugs (including replace‑into replication problems), and proposes both operational and kernel‑level solutions.
This article investigates why MySQL master‑slave replication can exhibit a one‑second difference in datetime fields when using server‑side prepared statements, analyzing binlog generation, InnoDB rounding, and providing code examples, root‑cause explanation, and mitigation strategies.
This report evaluates how enabling SSL encryption in MySQL affects transaction‑per‑second performance, compares the OpenSSL and yaSSL libraries across SSL connection and transparent encryption test groups, and analyzes the underlying CPU, I/O, and lock bottlenecks that cause the observed performance differences.
This article surveys the evolution, core concepts, and concrete implementation details of Linux task scheduling, illustrating kernel data structures, scheduling entities, run‑queue management, and the CFS algorithm with code excerpts and explaining how the scheduler balances interactive and background workloads.
The article explains how to use MySQL 8.0's SKIP LOCKED and NOWAIT clauses to implement a pure‑database seat‑reservation system, detailing transaction flow, possible lock outcomes, error handling, and the underlying InnoDB source‑code changes that enable these features.
A technical article detailing the investigation and resolution of a MySQL error related to insert buffer merge operations during table deletion, involving code analysis and system debugging.
This article examines a Linux 3.10 kernel soft‑lockup bug where the ext4 extent‑status LRU spin‑lock is held for over 20 seconds under memory pressure, explains the ext4 delayed‑allocation mechanism, block lookup process, extent‑status cache shrinkage, and presents the community's mitigation approach.
This article analyzes a MySQL master‑crash scenario where mismatched Read_Master_Log_Pos and Exec_Master_Log_Pos prevent HA failover, explains binlog event structures, and proposes updating Read_Master_Log_Pos only after a full transaction is received to ensure reliable asynchronous replication.
