system.dashboards

包含 /dashboard 页面（可通过 HTTP 接口 访问）所使用的查询。 该表对于监控和故障排查非常有用。表中每一行对应仪表盘中的一个图表。

注意

/dashboard 页面不仅可以渲染来自 system.dashboards 的查询，还可以渲染来自任意具有相同表结构的表的查询。 这对于创建自定义仪表盘很有帮助。

示例：

SELECT *
FROM system.dashboards
WHERE title ILIKE '%CPU%'

Row 1:
──────
dashboard: overview
title:     CPU Usage (cores)
query:     SELECT toStartOfInterval(event_time, INTERVAL {rounding:UInt32} SECOND)::INT AS t, avg(ProfileEvent_OSCPUVirtualTimeMicroseconds) / 1000000
FROM system.metric_log
WHERE event_date >= toDate(now() - {seconds:UInt32}) AND event_time >= now() - {seconds:UInt32}
GROUP BY t
ORDER BY t WITH FILL STEP {rounding:UInt32}

Row 2:
──────
dashboard: overview
title:     CPU Wait
query:     SELECT toStartOfInterval(event_time, INTERVAL {rounding:UInt32} SECOND)::INT AS t, avg(ProfileEvent_OSCPUWaitMicroseconds) / 1000000
FROM system.metric_log
WHERE event_date >= toDate(now() - {seconds:UInt32}) AND event_time >= now() - {seconds:UInt32}
GROUP BY t
ORDER BY t WITH FILL STEP {rounding:UInt32}

Row 3:
──────
dashboard: overview
title:     OS CPU Usage (Userspace)
query:     SELECT toStartOfInterval(event_time, INTERVAL {rounding:UInt32} SECOND)::INT AS t, avg(value)
FROM system.asynchronous_metric_log
WHERE event_date >= toDate(now() - {seconds:UInt32}) AND event_time >= now() - {seconds:UInt32} AND metric = 'OSUserTimeNormalized'
GROUP BY t
ORDER BY t WITH FILL STEP {rounding:UInt32}

Row 4:
──────
dashboard: overview
title:     OS CPU Usage (Kernel)
query:     SELECT toStartOfInterval(event_time, INTERVAL {rounding:UInt32} SECOND)::INT AS t, avg(value)
FROM system.asynchronous_metric_log
WHERE event_date >= toDate(now() - {seconds:UInt32}) AND event_time >= now() - {seconds:UInt32} AND metric = 'OSSystemTimeNormalized'
GROUP BY t
ORDER BY t WITH FILL STEP {rounding:UInt32}

列：

• dashboard (String) — 仪表盘名称。
• title (String) — 图表标题。
• query (String) — 用于获取要展示数据的查询。