PostgreSQL Checkpoint Spikes: Why p99 Explodes Every N Minutes
A reproducible approach to diagnose and eliminate checkpoint-induced latency spikes using pgbench, pg_stat_bgwriter, and WAL/IO budgeting.
#databases
4 posts
Database Connection Pool Exhaustion: The Silent Outage Trigger
App hangs but the database looks healthy. Your pool is exhausted. I show how to detect it, size pools sanely, and prevent connection leaks.
ClickHouse ReplacingMergeTree: The Deduplication Illusion
ReplacingMergeTree doesn't dedupe on SELECT. It merges eventually. Your queries return duplicates until background merge runs. Here's how to handle it.
Double Charges From Idempotency Keys: The Replica Lag Trap
Perfect idempotency logic, but customers still get charged twice. The cause: checking idempotency keys against a read replica that's seconds behind the primary during traffic spikes.