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Coordinator DB
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Measure query processing time ​

A stopwatch around an HTTP or native-client call measures connection setup, authentication, SQL processing and delivery of the result. Use the request's recorded measurements when you need to investigate processing rather than the full client journey.

Record the request ​

HTTP responses include X-Coordinator-Query-Id and X-Coordinator-Summary. Save these alongside the client's elapsed time. The summary includes elapsed_ms, result rows, read and write counters, and memory measurements. Native requests also appear in structured query history when logging is enabled.

sql
SELECT query_id, query_duration_ms, result_rows
FROM system.query_log
WHERE type = 'QueryFinish'
ORDER BY event_time DESC
LIMIT 10
FORMAT csv;

Query history is asynchronous; a direct single-table query waits for previously queued events. The observing request's own terminal event appears only after it finishes.

Avoid misleading comparisons ​

Use the same SQL, data and output format for repeated measurements. A large CSV response and a single aggregate row have different delivery costs. EXPLAIN ANALYZE executes the statement once and reports runtime measurements without returning its ordinary rows; analyzed writes still change data.

See HTTP response metadata, EXPLAIN and system.query_log.