Analyzing the 'pre-existing shared memory block' error when a PostgreSQL instance fails to start after OOM, with a deep dive into PG's three shared memory types and how to locate and clean up residual SysV shared memory
A 2025 summary of PostgreSQL operations experience covering CPU, memory, IO, WAL, autovacuum, locks, partitioned tables, connection pools, statistics, and other core operational topics with practical tips and troubleshooting
Analysis of UPDATE failure on new partitions without primary keys: partitioned tables under logical replication publications lack replica identity; PG11 publication mechanism combined with partition creation workflow results in new partitions missing both primary keys and indexes
Analyzing how high-concurrency updates on the same row cause massive row locks and LWLock LockManager waits, verifying through benchmarks that row locks bypassing the fastpath mechanism is the root cause of increased LWLock contention
Analysis of severely inaccurate n_distinct statistics, deep dive into the Haas-Stokes DISTINCT estimation algorithm in PostgreSQL source code and its estimation bias when sample size is much smaller than total rows
Analyzing a case where performance dropped after adding an index: the new index caused the optimizer to choose a different execution path, and the cached generic plan prevented ANALYZE from updating the erroneous cached plan
Analysis of GRANT authorization causing walsender to freeze: massive pg_class changes from bulk GRANT produce huge numbers of invalidation messages; logical decoding stalls due to pathman plugin's slow hash table traversal during invalidation processing
A summary of PostgreSQL operations experience in 2024, covering execution plan regressions, statistics collection strategies, connection pooling, vacuum, WAL, partitioned tables, and other common ops issues with quick diagnosis and resolution approaches
Deep analysis of PG startup flow where the startup process reading tens of millions of spill files causes slow startup, identifying the root cause through source code analysis of LSN structure and spill file naming rules
Deep source code analysis of PG shutdown flow and signal mechanisms, troubleshooting why walsender blocks fast shutdown: logical replication walsender cannot respond to SIGTERM while waiting for consumer feedback