An Old SQL Server Trick, Reborn. Changing a ClickHouse Sort Key Without Moving 4 TB

In my childhood we once had to move flats. We had a piano. It was HEAVY. Nobody could carry it. We tried three times, and on the third try the piano won.

Memory Forgets, Disks Remember: Binlog vs. WAL vs. Transaction Log

When your production server starts coughing up errors, a DBA does not cry. RAM is as forgetful as wedding vows, and only an append-only log on disk remembers our sins down to the exact microsecond. All three heavyweights: MySQL, PostgreSQL, and SQL Server rely on the same core concept (Write-Ahead Logging): carve β€œI changed this row” into granite first, flush the buffer to disk, and only then pretend the data safely lives in the tables. But the devil, as always, lives in details.