Compare Scenarios

Migration Step 1

Both scenarios define a migration step at this stage. Content Management Platform: triggered by 'Content read API p99 > 100ms during peak traffic; PostgreSQL'. Financial Ledger Platform: triggered by 'Audit requirement to reconstruct account state at any histor'.

Migration Step 2

Both scenarios define a migration step at this stage. Content Management Platform: triggered by 'Full-text search p99 > 500ms; inability to implement faceted'. Financial Ledger Platform: triggered by 'Kafka publish failures causing financial transaction rollbac'.

Migration Step 3

Both scenarios define a migration step at this stage. Content Management Platform: triggered by 'Month-end content performance reports generating sequential '. Financial Ledger Platform: triggered by 'Financial dashboard query p99 > 500ms causing dashboard-driv'.

PostgreSQL pg_stat_statements showing > 10 distinct query patterns with high call counts from the content list API path; database queries per second growing linearly with API request rate for content list endpoints (should be sub-linear with proper batch fetching); p99 for content list API > 200ms during moderate traffic

Tier 1: N+1 Query Amplification: ORM-level N+1 patterns in content relationship traversal: author fetch, category fetch, related content fetch as independent queries per article. Recommended evolution: Audit every content API response with query logging enabled and count queries per request for each content type; implement eager loading for all included relationships (JOIN for 1:1, IN-clause batch for 1:N); validate that content list endpoints produce a fixed number of queries regardless of list size (O(1) queries, not O(N)); add a query count assertion to integration tests for content list endpoints to prevent regression .

PostgreSQL read replica CPU spike correlated exactly with publish events; Redis cache hit rate dropping to near 0% immediately after publish for popular content; content API p99 spiking from < 20ms to > 500ms during the 1–3 second window after a high-traffic content item is published

Tier 2: Cache Invalidation Thundering Herd: Cache key deletion on publish triggering simultaneous cache miss stampede for all concurrent readers of popular content. Recommended evolution: Implement cache-aside with probabilistic early expiration (PER): before the cache TTL expires, a fraction of reads proactively refresh the cache value while other reads continue serving the cached value; this eliminates the hard expiry boundary that causes simultaneous misses; alternatively, on publish, write the new content value directly into the cache key before invalidating the old one (update-in-place rather than delete-and-miss) to eliminate the invalidation gap .

pg_locks shows contended rows on accounts table; write p99 > 50ms; deadlock errors in application logs; pg_stat_activity showing many transactions waiting for RowExclusiveLock on the same account rows

Tier 1: Hot Account Lock Contention: Concurrent debit/credit transactions competing for the same account row versions. Recommended evolution: Implement optimistic locking with version column and retry; or queue concurrent updates for the same account entity through an account-scoped serialization queue at the application layer; or partition the accounts table by account range .

Write p99 > 100ms with synchronous_commit = remote_apply; replica WAL apply lag visible in pg_stat_replication; network jitter between primary and replica causing write latency spikes correlating with replication ACK delays

Tier 2: Synchronous Replication Write Latency: Synchronous replication write-ahead wait amplifying network latency for every committed transaction. Recommended evolution: Co-locate primary and replica in the same availability zone for lowest replication RTT; tune wal_sender_timeout and recovery_min_apply_delay; evaluate whether synchronous_commit = on (durable to primary WAL only) is acceptable for your regulatory risk model .