Кейсы

middle⏱ 25 min

PostgreSQL Connection Pool Exhaustion

It's 14:30 on Black Friday. Your monitoring alerts fire: response times have spiked.

PostgreSQLHikariCPJava

⚙️application · jvm

senior⏱ 35 min

JVM Memory Leak Under Load

Your analytics API handles 200 RPS flawlessly in staging.

JVMHeap DumpJava

NginxLoad Balancingupstream

🏗️infrastructure · nginx

junior⏱ 20 min

Nginx Load Balancer Misconfiguration

Your team deployed a new feature yesterday. Today the SRE reports one backend node is running at 94% CPU while the other four are nearly idle.

PostgreSQLEXPLAIN ANALYZEIndex

junior⏱ 15 min

PostgreSQL Sequential Scan on 67M Rows

The daily financial report job has always run at 03:00 UTC and finished in under 1 minute.

⚙️application · jvm

middle⏱ 30 min

Tomcat Thread Pool Starvation

The booking API handles steady-state load (150 RPS) perfectly — P95 under 120ms.

JavaTomcatThread Pool

PostgreSQLDeadlockTransactionspg_locks

senior⏱ 30 min

PostgreSQL Deadlock Under Concurrent Writes

Two services write to the same tables in opposite order. Transactions lock each other indefinitely.

PostgreSQLReplicationWALpg_stat_replication

senior⏱ 35 min

Read Replica Replication Lag Spike

Read replica falls 45 minutes behind primary. Read queries returning stale data.

⚙️application · jvm

senior⏱ 40 min

G1GC Stop-The-World Pause Spikes

Random 8-12 second latency spikes with no CPU or memory pressure. GC logs hold the answer.

JVMG1GCHeapGC Tuning

🏗️infrastructure · linux

middle⏱ 25 min

Disk I/O Saturation on Write-Heavy Workload

Write throughput drops 70% under load. iostat shows 100% disk utilization.

LinuxiostatDisk I/Ofio

PrometheusGrafanaAlertingSLO

📊monitoring · prometheus

middle⏱ 22 min

Alert Fatigue: Tuning Prometheus Rules

Team receives 200+ alerts per day. On-call engineers start ignoring them.