Event schema
Fields the query expects
| Field | Type | Why it exists |
|---|---|---|
| timestamp_utc | Timestamp | Query completion time. |
| database_system | Utf8 | Database system name. |
| operation_name | Utf8 | SELECT, INSERT, or another controlled operation. |
| query_fingerprint | Utf8 | Normalized statement shape without values. |
| duration_ms | Float64 | Application-observed query duration. |
| request_id | Utf8 | Safe parent request identifier. |
Copy the query
SELECT
database_system,
operation_name,
query_fingerprint,
COUNT(*) AS calls,
SUM(duration_ms) AS total_time_ms,
approx_percentile_cont(duration_ms, 0.95) AS p95_duration_ms,
COUNT(DISTINCT request_id) AS affected_requests
FROM database_query_events
WHERE timestamp_utc >= now() - INTERVAL '24 hours'
GROUP BY database_system, operation_name, query_fingerprint
ORDER BY total_time_ms DESC
LIMIT 20;This read-only query is planned and executed against an empty typed table with Apache DataFusion 45.2.0. We review the synthetic sample output separately. Check field types, thresholds, and counting rules against your own data. Read the testing methodology.
Query result
Total query time by fingerprint
The project list has lower tail latency but consumes more aggregate request time.
| database_system | operation_name | query_fingerprint | calls | total_time_ms | p95_duration_ms | affected_requests |
|---|---|---|---|---|---|---|
| postgresql | SELECT | project-list-v4 | 18,400 | 1,288,000 | 142 | 9,200 |
| postgresql | SELECT | monthly-report-v2 | 420 | 924,000 | 4,180 | 410 |
Synthetic example output. Run the query against your own event schema and thresholds before using it for operational decisions.
Reproduce the example
Download the sample data
The JSON bundle includes the event schema with field types, illustrative input rows, exact SQL, expected output, review notes, and engine version. The CSV contains the displayed result.
How the SQL works
- 1Total time combines volume and latency into an impact ranking.
- 2p95 keeps a low-volume pathological query visible.
- 3Affected requests distinguishes repeated calls such as N+1 behavior.
Edge cases to check
- Application duration includes pool and network effects unless separately instrumented.
- Never log bound SQL values.
- Sampling needs weighted counts before comparing total impact.
Recommended dashboard
- Bars: total_time_ms by fingerprint
- Table: calls, p95, and affected requests
- Trend: total query time by release
Alert guidance
Review sustained total-time growth; page only when it drives a customer-facing reliability objective.
Read alert setupSet up the events this query needs
Related instrumentation and guides
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