table bloat — 2 Technical Articles

Sep 17, 2025 · Databases

How a DDL Change Can Double MySQL Table Size: The Hidden B+Tree Page‑Split Bug

After a normal DDL change on the OneDBA platform, a table's storage grew nearly 100% and some queries slowed down, revealing a MySQL InnoDB B+Tree page‑split flaw that stores only one row per 16KB page when large records are inserted, which also corrupts statistics and leads to slow SQL.

B+TreeDDLInnoDB

0 likes · 24 min read

How a DDL Change Can Double MySQL Table Size: The Hidden B+Tree Page‑Split Bug

ITPUB

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