MySQL Instant DDL: Metadata Locks, Waiting Writers, and Query Pileups

A transaction reads one row and then remains open. Later, a deployment adds a column using ALTER TABLE ... ALGORITHM=INSTANT. The migration waits. A new request issues an ordinary SELECT against the same table, and that request waits too. The original query has already finished. The schema change requires no table rebuild. The new query accesses a... Weiterlesen: MySQL Instant DDL: Metadata Locks, Waiting Writers, and Query Pileups