04Ship a schema change to a live service with no downtime. Walk me through the sequence.▼hard★ EssentialNewStripeShopifyGitLab2 repliesunlockedThe deployment question that has a real answer and a real trap. Code and schema deploy at different speeds, and any step where they must change together is the step that causes the outage.Open full answer →
13Checkout is failing with 'connection pool exhausted', but the database CPU sits at 10 percent. Where is the problem?▼mediumNewFlipkartRazorpayWalmart Global Tech○ sign inAn idle database with a starved application is the tell. The connections are held, not used. More database capacity does not release leaked connections.Open full answer →
45Last night's failover left both database nodes accepting writes for four minutes. Finance wants to know which orders are real.▼hard★ EssentialNewJPMorgan ChasePhonePeOracle◆ premiumSplit-brain writes are a fencing failure first and a data problem second. Freeze writes, read the divergence boundary from replication positions, and let the payment ledger arbitrate reality.Open full answer →
05Make a Postgres database highly available. What are you actually promising, and what breaks?▼hard★ EssentialNewAmazonRazorpaySnowflake2 repliesunlockedEvery candidate says replication and failover. The scoring answer names the replication mode, states the resulting data loss window, and explains how the cluster avoids two primaries.Open full answer →
