Compare Scenarios

Migration Step 1

Both scenarios define a migration step at this stage. Read-Heavy SaaS API: triggered by 'Connection pool exhaustion or p99 read latency > 200ms under'. Gaming Backend Platform: triggered by 'Single game server instance running at connection ceiling; h'.

Migration Step 2

Both scenarios define a migration step at this stage. Read-Heavy SaaS API: triggered by 'Primary CPU > 70% during peak read hours'. Gaming Backend Platform: triggered by 'Game server instances blocking on PostgreSQL writes at end-o'.

Migration Step 3

Gaming Backend Platform has a defined migration; Read-Heavy SaaS API does not at this stage.

p99 database latency rising; connection wait queue growing; requests timing out with "too many connections" or pool queue full errors

Tier 1: Connection Exhaustion: Database connection pool saturated or max_connections exceeded. Recommended evolution: Add PgBouncer connection pooler in transaction mode.

Database CPU > 80% sustained; read query p99 rising; cache miss rate stable but overall latency increasing

Tier 2: Read Throughput Ceiling: Single PostgreSQL primary saturated with read traffic. Recommended evolution: Add one or more streaming read replicas; implement lag-aware replica routing.

Game server instance file descriptor count approaching OS limit (typically 65k open connections); WebSocket accept latency increasing; new connection establishment p99 > 200ms; CPU on game server instances > 70% during peak concurrent player count

Tier 1: WebSocket Connection Ceiling per Instance: Single game server instance WebSocket connection count limit; OS-level fd_max or application-level connection accept queue saturation. Recommended evolution: Increase OS fd_max to 512k and application connection accept queue depth; tune SO_REUSEPORT to allow multiple accept threads per socket; add game server instances and update consistent hashing ring; the affinity layer automatically routes new game rooms to the new instances as the ring expands: existing rooms are unaffected .

Redis command throughput > 500k/second; Redis CPU > 60%; per-tick Redis write latency p99 > 5ms (above the acceptable state sync threshold); game tick rate visibly dropping below target (30 ticks/second falling to 20) under load

Tier 2: Redis Game State Write Amplification: Game state serialization to Redis per tick producing more writes than expected; unoptimized state struct serialization writing entire state blob on any field change. Recommended evolution: Implement delta state serialization: only changed fields are written to Redis per tick using HSET with only the modified keys, not full state replacement; profile Redis command distribution per game tick to identify specific state fields with high churn; consider moving ephemeral per-tick state (player positions, projectile states) to local server memory with only durable state (scores, inventory changes) written to Redis .