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Apr 22, 2023 · Databases

Why PostgreSQL Vacuums Can’t Reclaim Space After Deletes and Updates

The article examines why PostgreSQL tables often retain large disk footprints after massive inserts, updates, and deletions, showing experiments on PG 13/PG 14, analyzing factors such as long‑running transactions, replication slots, uncommitted transactions, fillfactor settings, and the old_snapshot_threshold bug, and offering practical diagnostics and mitigation steps.

PostgreSQLVacuumfillfactor
0 likes · 8 min read
Why PostgreSQL Vacuums Can’t Reclaim Space After Deletes and Updates
Aikesheng Open Source Community
Aikesheng Open Source Community
Aug 9, 2019 · Databases

InnoDB Index Build Process and Fill Factor in MySQL 5.7+

Since MySQL 5.7 InnoDB builds secondary indexes using a bottom‑up, sorted‑index approach, the article explains the three build phases, presents a step‑by‑step B‑tree construction example with SQL code, and discusses the innodb_fill_factor setting, its impact, advantages, and drawbacks.

B+TreeInnoDBMySQL
0 likes · 11 min read
InnoDB Index Build Process and Fill Factor in MySQL 5.7+