Query Audit Trail Gaps

The Problem

Insufficient logging of RAG queries and retrieved context makes it impossible to audit data access, investigate security incidents, or prove compliance.

Symptoms

• ❌ Cannot track who queried what

• ❌ No record of retrieved sensitive data

• ❌ Missing timestamps for access

• ❌ Cannot investigate data breaches

• ❌ Compliance audit failures

Real-World Example

Security incident:
→ Confidential document leaked
→ Need to find: Who accessed it?

Check logs:
→ Application logs: Generic "query processed"
→ Vector DB logs: No query content logged
→ LLM API logs: Retained 30 days (too old)

Cannot determine:
→ Which user queried the document
→ When it was accessed
→ What context was retrieved
→ If data was exfiltrated

Forensic investigation impossible

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Deep Technical Analysis

Logging Gaps

Application-Level Logging:

Typical logs:
"User 123 submitted query" ✓
"Retrieved 5 chunks" ✓

Missing:
- Query text content ✗
- Retrieved chunk IDs ✗
- Document sources ✗
- Sensitivity labels ✗
- User IP address ✗

Vector DB Logging:

Pinecone/Weaviate:
→ Operational metrics (latency, errors)
→ But: No query content logged
→ Privacy by design (good for user privacy)
→ Bad for audit trail (cannot reconstruct access)

LLM API Logging:

OpenAI/Anthropic:
→ 30-day retention (default)
→ Then deleted
→ Insufficient for compliance (HIPAA: 6 years)

Must log locally:
→ Before sending to API
→ Full request/response
→ Long-term retention

Comprehensive Audit Log

Required Fields:

{
  "timestamp": "2024-01-15T14:32:18Z",
  "user_id": "user_12345",
  "session_id": "sess_abc123",
  "ip_address": "192.168.1.100",
  "query": "What is the CEO's compensation?",
  "agent_id": "hr_agent",
  "retrieved_chunks": [
    {
      "chunk_id": "doc_789_chunk_12",
      "document": "Executive Compensation 2023",
      "sensitivity": "confidential",
      "score": 0.87
    }
  ],
  "response": "According to...",
  "response_time_ms": 1234,
  "model": "gpt-4",
  "tokens_used": 567
}

Storage Requirements:

For compliance:
→ Immutable storage (append-only)
→ Encrypted at rest
→ Retention: 6+ years (HIPAA)
→ Searchable for investigations
→ Access-controlled (who can view logs?)

Performance Impact

Logging Overhead:

Synchronous logging:
→ Write to DB before response
→ Adds latency (50-200ms)
→ User waits for log write

Asynchronous logging:
→ Queue log event
→ Write in background
→ Minimal latency impact
→ Risk: Log loss if crash before flush

Storage Costs:

High-volume system:
→ 10,000 queries/day
→ 5 KB per log entry
→ = 50 MB/day = 18 GB/year
→ × 6 years retention = 108 GB

Plus retrieved chunks:
→ 10 chunks × 500 tokens each = 5,000 tokens/query
→ 50 MB/day just for chunk content
→ Substantial storage

Audit Query Interface

Investigations:

Security team needs:
→ "Show all queries accessing document X"
→ "Who accessed salary data last month?"
→ "Find queries from IP 1.2.3.4"

Requires:
→ Indexed logs (ElasticSearch, Splunk)
→ Query interface
→ Role-based access (only security team)

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How to Solve

Log query, user, timestamp, retrieved chunks, and response for every request + use structured logging (JSON) with all required fields + implement async logging to minimize latency + store in immutable append-only storage + retain 6+ years for compliance + index logs for searchable audit trail. See Audit Logging.