Slow Queries

The slow queries endpoint returns the most time-consuming queries executed within a given period, enabling performance engineers to identify and optimize bottlenecks.

Endpoint

GET /v1/analytics/slow-queries

Query Parameters

Parameter	Type	Default	Description
`days`	int	7	Time period to analyze
`limit`	int	10	Maximum number of slow queries to return

curl Example

curl "http://query-engine:8080/v1/analytics/slow-queries?days=7&limit=5" \
  -H "Authorization: Bearer $JWT_TOKEN"

[
  {
    "executionId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "queryText": "SELECT o.*, c.name FROM orders o JOIN customers c ON o.customer_id = c.id WHERE o.created_at > '2026-01-01' ORDER BY o.total DESC",
    "engineType": "TRINO",
    "executionTimeMs": 34200,
    "bytesScanned": 2147483648,
    "rowCount": 50000,
    "userId": "6ba7b810-9dad-11d1-80b4-00c04fd430c8",
    "submittedAt": "2026-02-10T14:30:00Z",
    "status": "COMPLETED"
  },
  {
    "executionId": "b2c3d4e5-f6a7-8901-bcde-f12345678901",
    "queryText": "SELECT product_category, region, SUM(revenue) FROM sales_facts GROUP BY CUBE(product_category, region)",
    "engineType": "TRINO",
    "executionTimeMs": 28500,
    "bytesScanned": 5368709120,
    "rowCount": 1200,
    "submittedAt": "2026-02-11T09:15:00Z",
    "status": "COMPLETED"
  }
]

Implementation

The controller retrieves slow queries from the analytics service and applies the limit:

@GetMapping("/slow-queries")
public ResponseEntity<List<QueryAnalytics.QueryInfo>> getSlowQueries(
        @RequestParam(defaultValue = "7") int days,
        @RequestParam(defaultValue = "10") int limit) {
 
    UUID tenantId = SecurityUtils.getCurrentTenantId();
    QueryAnalytics analytics = analyticsService.getAnalytics(tenantId, days, "day");
    return ResponseEntity.ok(analytics.getTopSlowQueries().stream()
            .limit(limit)
            .toList());
}

Failed Queries

A separate endpoint returns recent failed queries for debugging:

curl "http://query-engine:8080/v1/analytics/failed-queries?days=7&limit=10" \
  -H "Authorization: Bearer $JWT_TOKEN"

[
  {
    "executionId": "c3d4e5f6-a7b8-9012-cdef-123456789012",
    "queryText": "SELECT * FROM nonexistent_table",
    "engineType": "TRINO",
    "executionTimeMs": 120,
    "errorMessage": "Table 'iceberg.analytics.nonexistent_table' does not exist",
    "submittedAt": "2026-02-12T08:45:00Z",
    "status": "FAILED"
  }
]

Insights Query Patterns