Posts

Analysis of DELETE throwing 'attempted to delete invisible tuple' while SELECT works fine, tracing through source code to identify VM file corruption as the root cause of the visibility check anomaly

An essay about visiting elderly grandparents in their hometown — observations on daily life in a mining community, elderly dependence on medication, the technology gap, and reflections on intergenerational bonds

Analyzing the counterintuitive phenomenon where a smaller ORDER BY LIMIT value runs slower, caused by the optimizer underestimating the cost of a backward index scan and choosing the wrong index

2023 Year-End Summary: A year of comprehensive PostgreSQL learning, including extracurricular reading rankings, reflections on writing and WeChat official account operations, and thoughts on active learning methodology

Analyzing why an UPDATE became slower after adding partition key filter conditions. The root cause was that partition permission checks caused the optimizer to select the wrong index for all partitions instead of a more selective index.

In-depth analysis of Oracle index split contention wait event enq: TX - index contention, its root causes, and six solutions including reverse indexes, hash-partitioned indexes, and partition table scattering.

Analysis of PostgreSQL's mechanism for initializing the data dictionary via BKI files in bootstrap mode, answering how basic system tables are accessed when pg_class doesn't exist yet

A sharing at the PostgreSQL Technology Summit Chengdu stop, covering the history of transactions, flaws in the ANSI SQL-92 standard, and the implementation of SSI (Serializable Snapshot Isolation) in PostgreSQL

A primer on HikariCP connection pooling: decoding core parameters, connection pool sizing formulas, and analyzing the impact of database connection count on performance with best practices.

Analyzes why a unique index scan accesses multiple data pages due to broken HOT chains and index bloat, diving deep into btree index version management and dead tuple cleanup mechanisms.