This article explains the purpose, differences, and proper usage of Spring validation annotations such as @NotNull, @NotBlank, @NotEmpty, as well as the @Valid and @Validated triggers, providing Maven dependency setup and concrete code examples for effective backend data validation.
A production MySQL server suffered CPU overload and half‑hour alerts because a high‑volume query skipped a crucial composite index field, leading to full‑table scans; the post explains the root cause, the temporary index fix, the left‑most index principle, code validation oversights, and lessons learned.
A production MySQL server was overwhelmed by a high‑volume query that ignored a crucial composite index because the leftmost key was missing, leading to full‑table scans, CPU saturation, and a half‑hour outage, and the post explains how the issue was diagnosed and fixed.
A production MySQL server was overwhelmed by a full‑table‑scan query that omitted the leftmost index column, causing CPU saturation and read‑only alerts; the article explains the root cause, temporary mitigation, the leftmost‑match principle, code‑level bug, and key lessons learned.
