Implemented comprehensive database query tracking to identify clients causing
high CPU usage through excessive database queries. The relay now tracks and
displays query statistics per WebSocket connection in the admin UI.
Features Added:
- Track db_queries_executed and db_rows_returned per connection
- Calculate query rate (queries/minute) and row rate (rows/minute)
- Display stats in admin UI grouped by IP address and WebSocket
- Show: IP, Subscriptions, Queries, Rows, Query Rate, Duration
Implementation:
- Added tracking fields to per_session_data structure
- Increment counters in handle_req_message() and handle_count_message()
- Extract stats from pss in query_subscription_details()
- Updated admin UI to display IP address and query metrics
Use Case:
Admins can now identify abusive clients by monitoring:
- High query rates (>50 queries/min indicates polling abuse)
- High row counts (>10K rows/min indicates broad filter abuse)
- Query patterns (high queries + low rows = targeted, high both = crawler)
This enables informed decisions about which IPs to blacklist based on
actual resource consumption rather than just connection count.
- Move non-NIP-17 admin functions from dm_admin.c to api.c for better architecture
- Add NIP-44 encryption to send_admin_response() for secure admin responses
- Implement SQL query validation and execution with safety limits
- Add unified SQL query handler for admin API
- Fix buffer size for encrypted content to handle larger responses
- Update function declarations and includes across files
- Successfully test frontend query execution through web interface
