Field notes from production MySQL work.
October 26, 2026 · QueryKings
A replica broke and you need a new one by morning. Here is how the InnoDB clone plugin, storage snapshots, and mysqldump/mydumper actually compare on wall-clock time, source impact, and binlog retention — and the GTID detail that decides whether the new replica starts cleanly.
Read moreOctober 19, 2026 · QueryKings
The buffer pool is not the whole memory budget. Here is how to account for per-connection buffers, internal temporary tables, and the performance schema, how to read what the server is actually using, and how to size an instance so the kernel never has to choose a victim.
Read moreOctober 12, 2026 · QueryKings
Teams keep their job queue and transactional outbox in MySQL because it keeps the work and the write in one transaction. Here is how SELECT ... FOR UPDATE SKIP LOCKED actually behaves under InnoDB, the index and polling design that keeps it cheap, and the three failure modes it leaves on the table.
Read moreOctober 5, 2026 · QueryKings
Most MySQL fleets still replicate on binlog file and position. GTIDs are a prerequisite for sane failover, for RDS and Aurora cutovers, and for the 8.4 tooling you will meet soon. Here is the online enablement sequence, state by state, plus the statements it outlaws and the errant-transaction trap waiting at the end.
Read moreSeptember 28, 2026 · QueryKings
OFFSET pagination reads and throws away every row it skips, so page 1 is fast and page 10,000 times out. Here is the mechanism, how to see it in EXPLAIN ANALYZE, the keyset (seek) rewrite, and what to do when the product team insists on jump-to-page 4,812.
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