Advanced database query optimization when indexes are already optimal: Hash Join memory spills to disk, the art of application-side joins without N+1, deterministic SELECT-then-write ID ordering, and 4 dangerous traps of ON DUPLICATE KEY UPDATE.
RPO, RTO, backup strategies, point-in-time recovery, logical vs physical backups, and disaster recovery planning.
Deep-dive into all 5 isolation anomalies (dirty read, non-repeatable, phantom, lost update, write skew), the 4 standard isolation levels, PostgreSQL vs MySQL vs Oracle implementation differences, snapshot scope (per-statement vs per-transaction), practical fix strategies without raising isolation, and the spec vs implementation distinction.
Physical engine mechanics of large-scale database exports: why LIMIT OFFSET degrades linearly, keyset pagination pitfalls, Go streaming vs Java JDBC OutOfMemoryError, and an anatomy of the net_write_timeout socket failure.
Physical mechanisms of long-running transaction failures: Undo tablespace and History List Length (HLL) bloat, the single-threaded rollback trap, the critical difference between KILL QUERY and KILL CONNECTION, and the Metadata Lock (MDL) queue cascade exhausting connection pools.
Deep dive into high-concurrency inventory reservation architectures — why Redis dual-writes cause overselling and underselling, how MySQL 8 SKIP LOCKED eliminates row contention, and how Shopify scaled to $5.1M GMV/minute during Black Friday.
Chi tiết cơ chế đánh index MySQL nâng cao: phân biệt Seek vs Filter, quy tắc Leftmost Prefix, ESR rule, Index Condition Pushdown (ICP), Skip Scan, và kỹ thuật Deferred Join tăng tốc 148 lần.
Online Schema Change mechanics in MySQL and PostgreSQL: why staging finishes in 40s while production exhausts connection pools, ALGORITHM & LOCK matrix, innodb_online_alter_log_max_size overflow, gh-ost vs pt-osc, and PostgreSQL's INVALID index trap.
Deep dive into MySQL InnoDB storage engine locking mechanics: why two users updating distinct draft carts trigger Deadlock 1213, decoding the 3 access paths of a WHERE clause, and why READ COMMITTED won't save you.
