Caching

Atlassian is implementing a JQL Subscription Service (JQS) to cache JQL query results, significantly reducing database load and improving response times. The initial approach involved a read-through cache with TTL or event-based invalidation, but this proved insufficient due to JQL's per-user, temporal, and equivalence complexities. The second iteration, JQL Splitting, parses JQL into Stage 1 (non-dynamic clauses cached) and Stage 2 (dynamic clauses executed at request time), resolving most caching issues. Permissions are handled by executing Stage 2 with per-user context.