Challenges

Real production decisions. Defend your call against a senior engineer, then get scored against an answer key. How it works

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6 of 53 challenges

Databases

6

LockedNightly Backups Run. Are You Actually Covered?Automated backups have run for months. A teammate says you are fully covered for disasters. Defend whether you agree.beginner8 minbeginner8 min
LockedAdd a NOT NULL Column to a 50M-Row Prod TableA migration adds a NOT NULL column to a huge live table. A teammate wants to run the ALTER directly. Defend the safe path.intermediate14 minintermediate14 min
LockedEvery Deploy Hammers the Database for 10 Minutes. Bigger DB?Each deploy flushes the cache and the database melts for 10 minutes while it refills. A teammate wants to double the database size. Defend fixing the stampede instead of paying for peak.intermediate12 minintermediate12 min
LockedFailover Lost 5 Minutes of Writes. Promise Zero Data Loss?An async-replica failover dropped five minutes of committed writes. Leadership demands zero data loss with zero performance impact. Defend the honest trade-off.advanced14 minadvanced14 min
LockedThe Nightly Report Is Slow. Just Run It in One Big Transaction?A nightly report holds one Postgres transaction open for hours and writes are bloating. A teammate wants a bigger box and higher timeouts. Defend the real fix.advanced13 minadvanced13 min
LockedYour Primary Region Is Down. Fail Over Now?The primary region is degraded. A teammate wants to flip DNS to the standby immediately. Defend whether and how you fail over.advanced15 minadvanced15 min