NOTE
MySQL SHOW PROFILE
Historical per-query profiling and modern alternatives for diagnosing query execution.
This is a historical learning note and may contain outdated or incomplete understanding.
SHOW PROFILE/SHOW PROFILES were historical MySQL profiling commands and should not be the default basis for modern diagnosis. Use EXPLAIN/EXPLAIN ANALYZE where supported, the Performance Schema, statement summaries, slow-query logs, and system metrics.
The important workflow is to identify where time or rows are spent, verify the execution plan against real cardinalities, and correlate SQL behavior with CPU, I/O, locks, and downstream resource pressure.