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.
This article introduces MySQL 8.0's resource group feature, detailing its concepts, configuration commands, query hint usage, and the underlying implementation including new parser classes, platform APIs, runtime components, performance schema integration, and persistence mechanisms, with code examples throughout.
The Tencent CMongo team analyzed severe memory consumption, slow queries, and hour‑long startup caused by millions of MongoDB collections, identified bottlenecks in WiredTiger’s data‑handle management and schema‑lock handling, and introduced a shared‑table‑space architecture that reduces WT tables to a handful, achieving 1‑2 order‑of‑magnitude speedups and eliminating OOM failures.
This article demonstrates how to use the RETURNING clause in Tencent Cloud Enterprise MySQL to retrieve inserted, replaced, or deleted rows directly, showing step‑by‑step examples with images and explaining the behavior of RETURNING, REPLACE RETURNING, and DELETE RETURNING statements.
At the 2021 ACM SIGMOD conference in Xi'an, Tencent Cloud Database TDSQL team had two papers accepted, introducing the innovative Spitfire three-tier buffer manager and adaptive multilevel serializability models, marking significant breakthroughs in database technology.
This article introduces the TXSQL query optimizer built on MySQL 8.0.22, detailing its cascades‑style framework, transformation rewrite rules such as outer‑join elimination and subquery flattening, join‑order heuristics, cost‑model configuration, and execution strategies, providing a comprehensive overview of its design and enhancements.
This article examines how slave crashes in MySQL replication can cause inconsistencies between master info and relay log positions, leading to duplicate events and errors such as 1062 and 1032, analyzes underlying mechanisms, presents case studies, and proposes configuration settings to achieve server‑crash‑safe replication.
This article provides a comprehensive overview of MySQL InnoDB's lock subsystem, describing its data structures, lock compatibility matrices, lock/unlock workflows, lock splitting, inheritance and migration, and presents several optimization techniques such as avoiding lock_sys mutex, asynchronous deadlock detection, and lock_sys mutex sharding to alleviate contention in MySQL 5.7 and later versions.
Tencent Cloud's native database team announced two breakthrough research papers—Spitfire, a three‑tier buffer manager for DRAM and NVM, and TLBtree, a read/write‑optimized tree index for non‑volatile memory—both accepted at top‑tier conferences SIGMOD and ICDE, highlighting novel memory‑aware storage techniques and collaborative achievements with leading universities.
TXRocks is a transactional storage engine based on RocksDB that offers significant space savings compared to InnoDB while maintaining comparable performance, with optimizations including sum operator pushdown and AEP-based secondary caching to address RocksDB's read performance limitations.
This article explains the purpose and usage of MySQL character set system variables, illustrates how they affect client‑server communication and file handling, and provides practical examples and diagrams to help developers correctly configure character sets for optimal performance.
