OpenEvidence Performance Tuning

Overview

Optimize OpenEvidence clinical query performance for point-of-care response times.

Prerequisites

• OpenEvidence integration running
• Monitoring configured (see openevidence-observability)
• Understanding of caching strategies
• Access to performance metrics

Performance Targets

| Metric | Target | Critical | |--------|--------|----------| | Clinical Query P50 | < 3s | > 10s | | Clinical Query P95 | < 8s | > 15s | | Clinical Query P99 | < 15s | > 30s | | DeepConsult Start | < 5s | > 15s | | Cache Hit Rate | > 70% | < 50% |

Instructions

Step 1: Query Optimization

// src/services/optimized-query.ts

// 1. Optimize question structure
function optimizeQuestion(question: string): string {
  // Remove unnecessary words
  let optimized = question
    .replace(/\b(please|can you|could you|I want to know)\b/gi, '')
    .replace(/\s+/g, ' ')
    .trim();

  // Ensure question ends with ?
  if (!optimized.endsWith('?')) {
    optimized += '?';
  }

  return optimized;
}

// 2. Optimize context to reduce processing
function optimizeContext(context: ClinicalContext): ClinicalContext {
  return {
    specialty: context.specialty,
    urgency: context.urgency,
    // Only include relevant patient context
    ...(context.patientAge && { patientAge: context.patientAge }),
    ...(context.patientSex && { patientSex: context.patientSex }),
    // Limit conditions to top 5 most relevant
    ...(context.relevantConditions && {
      relevantConditions: context.relevantConditions.slice(0, 5),
    }),
    // Limit medications to top 10
    ...(context.currentMedications && {
      currentMedications: context.currentMedications.slice(0, 10),
    }),
  };
}

// 3. Optimize query options
const OPTIMIZED_OPTIONS = {
  maxCitations: 5, // More citations = slower response
  includeGuidelines: true, // High value, low overhead
  includeDrugInfo: false, // Only when needed
  prioritizeRecent: true, // Faster index access
};

Step 2: Intelligent Caching Layer

// src/cache/clinical-cache.ts
import { createHash } from 'crypto';
import Redis from 'ioredis';

interface CacheConfig {
  redis: Redis;
  defaultTTL: number;
  maxEntries: number;
}

interface CachedResponse {
  data: any;
  cachedAt: number;
  ttl: number;
  hitCount: number;
}

export class ClinicalQueryCache {
  private redis: Redis;
  private defaultTTL: number;
  private prefix = 'oe:query:';

  constructor(config: CacheConfig) {
    this.redis = config.redis;
    this.defaultTTL = config.defaultTTL;
  }

  // Generate cache key from query
  private generateKey(question: string, context: ClinicalContext): string {
    const normalized = JSON.stringify({
      q: question.toLowerCase().trim(),
      s: context.specialty,
      u: context.urgency,
    });
    return this.prefix + createHash('sha256').update(normalized).digest('hex').substring(0, 16);
  }

  // Determine TTL based on query type
  private getTTL(question: string, context: ClinicalContext): number {
    const lowerQuestion = question.toLowerCase();

    // Short TTL for time-sensitive queries
    if (context.urgency === 'stat' || context.urgency === 'urgent') {
      return 300; // 5 minutes
    }

    // Longer TTL for stable medical facts
    if (lowerQuestion.includes('mechanism') ||
        lowerQuestion.includes('pharmacokinetics') ||
        lowerQuestion.includes('half-life')) {
      return 86400; // 24 hours
    }

    // Medium TTL for treatment guidelines (may update)
    if (lowerQuestion.includes('guideline') ||
        lowerQuestion.includes('first-line') ||
        lowerQuestion.includes('recommended')) {
      return 3600; // 1 hour
    }

    return this.defaultTTL;
  }

  async get(question: string, context: ClinicalContext): Promise<any | null> {
    const key = this.generateKey(question, context);
    const cached = await this.redis.get(key);

    if (!cached) return null;

    const entry: CachedResponse = JSON.parse(cached);

    // Increment hit count
    entry.hitCount++;
    await this.redis.setex(key, entry.ttl, JSON.stringify(entry));

    return entry.data;
  }

  async set(
    question: string,
    context: ClinicalContext,
    data: any
  ): Promise<void> {
    const key = this.generateKey(question, context);
    const ttl = this.getTTL(question, context);

    const entry: CachedResponse = {
      data,
      cachedAt: Date.now(),
      ttl,
      hitCount: 0,
    };

    await this.redis.setex(key, ttl, JSON.stringify(entry));
  }

  async invalidate(pattern?: string): Promise<number> {
    const keys = await this.redis.keys(this.prefix + (pattern || '*'));
    if (keys.length === 0) return 0;
    return this.redis.del(...keys);
  }

  async getStats(): Promise<{
    totalKeys: number;
    memoryUsage: string;
    hitRate: number;
  }> {
    const keys = await this.redis.keys(this.prefix + '*');
    const info = await this.redis.info('memory');

    let totalHits = 0;
    let totalEntries = 0;

    for (const key of keys.slice(0, 100)) {
      const cached = await this.redis.get(key);
      if (cached) {
        const entry: CachedResponse = JSON.parse(cached);
        totalHits += entry.hitCount;
        totalEntries++;
      }
    }

    return {
      totalKeys: keys.length,
      memoryUsage: info.match(/used_memory_human:(\S+)/)?.[1] || 'unknown',
      hitRate: totalEntries > 0 ? totalHits / totalEntries : 0,
    };
  }
}

Step 3: Connection Pooling & Keep-Alive

// src/openevidence/optimized-client.ts
import { OpenEvidenceClient } from '@openevidence/sdk';
import { Agent } from 'https';

// Reuse connections with keep-alive
const httpsAgent = new Agent({
  keepAlive: true,
  keepAliveMsecs: 30000,
  maxSockets: 10,
  maxFreeSockets: 5,
});

export const optimizedClient = new OpenEvidenceClient({
  apiKey: process.env.OPENEVIDENCE_API_KEY!,
  orgId: process.env.OPENEVIDENCE_ORG_ID!,
  httpAgent: httpsAgent,
  timeout: 30000,
});

// Pre-warm connections on startup
export async function warmupConnections(): Promise<void> {
  console.log('[Performance] Warming up OpenEvidence connections...');

  try {
    // Make a lightweight request to establish connection
    await optimizedClient.health.check();
    console.log('[Performance] Connection pool warmed up');
  } catch (error) {
    console.error('[Performance] Warmup failed:', error);
  }
}

Step 4: Request Batching

// src/services/batch-query.ts
import DataLoader from 'dataloader';

// Batch multiple clinical queries
const queryBatcher = new DataLoader<
  { question: string; context: ClinicalContext },
  ClinicalQueryResponse
>(
  async (queries) => {
    // OpenEvidence may support batch API in future
    // For now, parallelize within rate limits
    const results = await Promise.all(
      queries.map(q => optimizedClient.query({
        question: q.question,
        context: q.context,
      }))
    );
    return results;
  },
  {
    maxBatchSize: 5, // Respect rate limits
    batchScheduleFn: (callback) => setTimeout(callback, 50), // 50ms window
    cacheKeyFn: (query) => `${query.question}:${query.context.specialty}`,
  }
);

// Usage in service
export async function batchedQuery(
  question: string,
  context: ClinicalContext
): Promise<ClinicalQueryResponse> {
  return queryBatcher.load({ question, context });
}

Step 5: Response Streaming (When Available)

// src/services/streaming-query.ts
// Use streaming for faster perceived performance

export async function streamingClinicalQuery(
  question: string,
  context: ClinicalContext,
  onPartialResponse: (partial: string) => void
): Promise<ClinicalQueryResponse> {
  // Check if streaming is supported
  if (optimizedClient.supportsStreaming?.()) {
    const stream = await optimizedClient.query.stream({
      question,
      context,
    });

    let fullAnswer = '';

    for await (const chunk of stream) {
      fullAnswer += chunk.text;
      onPartialResponse(fullAnswer);
    }

    return stream.finalResponse;
  }

  // Fallback to regular query
  const response = await optimizedClient.query({ question, context });
  onPartialResponse(response.answer);
  return response;
}

Step 6: Performance Monitoring

// src/monitoring/performance-metrics.ts
import { Histogram, Counter, Gauge } from 'prom-client';

// Latency histogram
const queryLatency = new Histogram({
  name: 'openevidence_query_duration_seconds',
  help: 'Clinical query latency',
  labelNames: ['specialty', 'urgency', 'cached'],
  buckets: [0.5, 1, 2, 5, 10, 15, 30],
});

// Cache metrics
const cacheHits = new Counter({
  name: 'openevidence_cache_hits_total',
  help: 'Cache hit count',
});

const cacheMisses = new Counter({
  name: 'openevidence_cache_misses_total',
  help: 'Cache miss count',
});

// Current queue size
const queueSize = new Gauge({
  name: 'openevidence_queue_size',
  help: 'Current request queue size',
  labelNames: ['priority'],
});

// Instrumented query function
export async function instrumentedQuery(
  question: string,
  context: ClinicalContext,
  cache: ClinicalQueryCache
): Promise<ClinicalQueryResponse> {
  const timer = queryLatency.startTimer({
    specialty: context.specialty,
    urgency: context.urgency,
  });

  // Check cache first
  const cached = await cache.get(question, context);
  if (cached) {
    cacheHits.inc();
    timer({ cached: 'true' });
    return cached;
  }
  cacheMisses.inc();

  // Query API
  const response = await optimizedClient.query({ question, context });

  // Cache response
  await cache.set(question, context, response);

  timer({ cached: 'false' });
  return response;
}

Performance Checklist

• [ ] Query optimization applied
• [ ] Caching layer configured
• [ ] Connection pooling enabled
• [ ] Keep-alive connections
• [ ] Request batching where applicable
• [ ] Monitoring metrics collecting
• [ ] Performance baselines established

Output

• Optimized query construction
• Intelligent caching with TTL management
• Connection pooling for efficiency
• Performance metrics and monitoring

Error Handling

| Performance Issue | Detection | Resolution | |-------------------|-----------|------------| | High P95 latency | Metrics alert | Check cache hit rate, optimize queries | | Low cache hit rate | < 50% hits | Review TTL strategy, increase cache size | | Connection timeouts | Timeout errors | Check keep-alive, increase pool size | | Memory pressure | Redis alerts | Implement LRU eviction |

Resources

• Redis Caching Best Practices
• DataLoader Documentation

Next Steps

For cost optimization, see openevidence-cost-tuning.