Compare Scenarios

Migration Step 1

Both scenarios define a migration step at this stage. Event-Driven Analytics Pipeline: triggered by 'OLTP query performance degrading due to analytics query inte'. E-Commerce Order Platform: triggered by 'Payment provider timeout causing full checkout rollback and '.

Migration Step 2

Both scenarios define a migration step at this stage. Event-Driven Analytics Pipeline: triggered by 'Sub-minute analytics latency required; ETL scheduling overhe'. E-Commerce Order Platform: triggered by 'Product search p99 > 1s; faceted navigation (category + pric'.

Migration Step 3

E-Commerce Order Platform has a defined migration; Event-Driven Analytics Pipeline does not at this stage.

pg_replication_slots shows growing pg_wal_lsn delta for CDC slot; PostgreSQL WAL directory growing faster than expected

Tier 1: CDC Slot Lag: Debezium / CDC connector not keeping up with write volume. Recommended evolution: Increase CDC connector parallelism; review filtered topics vs full-table CDC; monitor slot lag as a first-class SLA .

Kafka consumer group lag growing; analytics dashboards increasingly stale; consumer CPU and network I/O near ceiling

Tier 2: Kafka Consumer Lag: Insufficient consumer parallelism or insufficient Kafka partitions. Recommended evolution: Increase topic partition count (note: keyed messages lose ordering when partitions added); add consumer replicas up to partition count .

PostgreSQL pg_locks showing high RowExclusiveLock contention on inventory_items for specific sku_ids; checkout p99 > 2s for contended SKUs; deadlock errors appearing in application logs during sale events; effective checkout throughput for hot SKUs well below per-request checkout latency would predict

Tier 1: Flash Sale Inventory Contention: Concurrent saga checkout attempts competing for the same inventory row via row-level locking. Recommended evolution: Introduce a per-SKU checkout serialization queue at the application layer : all concurrent checkout requests for the same SKU are queued and processed serially, converting lock contention into queue latency. Alternatively, use PostgreSQL advisory locks with non-blocking trylock: requests that cannot acquire the lock immediately return a "sold out" response rather than queuing. For very high flash sale volumes, pre-allocate inventory slots (reserve N slots per sale event, each slot is a row with one reservation) to spread lock contention across N rows instead of one. .

Checkout p99 tracking payment provider p99 almost linearly; connection pool utilization on the payment service rising during payment provider slowdowns; circuit breaker trip events appearing in payment service metrics; saga timeout events correlated with payment provider latency spikes

Tier 2: Payment Provider Latency Amplifying Checkout Latency: Checkout saga holding a database connection and an inventory reservation open for the duration of the payment provider call: payment latency directly amplifies connection pool pressure. Recommended evolution: Decouple the payment step from the synchronous checkout saga: reserve inventory and create the order record synchronously, then process payment asynchronously. The customer receives an "order confirmed, payment processing" state immediately; the payment step runs as a separate saga step triggered by an event. This reduces the synchronous checkout latency to the inventory reservation time, not the payment provider round-trip time. .