Design a log filtering and analytics service

Design a log processing service that ingests application logs and supports: ( 1) filtering logs by attributes such as service, level, and substring/pattern; ( 2) returning counts of error-level logs over a specified time window; and ( 3) building an hourly histogram for a specific log pattern or ID. Specify ingestion flow, storage and indexing (e.g., time-series partitioning, inverted indexes), and a query API such as filter(query), countErrors(window), and histogramByHour(query, window). Discuss handling late/duplicated events, scalability and partitioning, retention, correctness vs. latency trade-offs, schema design with example fields, and complexity analysis for common queries.