elasticsearch - Vega：在数据中添加缺失的信息

Question

在 kibana 中，在 Vega-lite 可视化中，我想随时间创建应用程序 (AAAA) 的转换状态图。（时间线）
状态具有固定值（初始化、开始、运行...）

在 x 轴上是时间戳，
在 Y 上是状态级别，
一个矩形或条形来跟踪状态级别。

|====
| ======
| ============
______________________________
t0 t1 t2 ....

我的数据来自 ElasticSearch 中的查询并具有以下格式。

timestamp  app  state
  t0    AAAA  Init
  t1    AAAA  start
  t2    AAAA  Running
  t3    AAAA  stopped

在 vega 中，我想用条形或矩形表示状态，例如：Init 状态将由从 t0 开始到 t1 结束的矩形表示。但我没有这个信息！t1 在下一条数据线

是否可以通过利用下一行来计算此值。数据会是这样。

timestamp  app  state    ends 
  t0    AAAA  Init         t1
  t1    AAAA  start        t2 
  t2    AAAA  Running      t3
  t3    AAAA  stopped      t4 

欢迎任何帮助。

Answer 1

您可以使用该操作通过窗口变换来执行此lead操作以查找下一个值。例如：

{
  "data": {
    "values": [
      {"timestamp": 0, "app": "A", "state": "init"},
      {"timestamp": 10, "app": "A", "state": "start"},
      {"timestamp": 25, "app": "A", "state": "run"},
      {"timestamp": 30, "app": "A", "state": "stop"},
      {"timestamp": 40, "app": "B", "state": "init"},
      {"timestamp": 55, "app": "B", "state": "start"},
      {"timestamp": 75, "app": "B", "state": "run"},
      {"timestamp": 85, "app": "B", "state": "stop"},
      {"timestamp": 90, "app": null, "state": "init"}
    ]
  },
  "transform": [
    {"window": [{"op": "lead", "field": "timestamp", "as": "t_stop"}]},
    {"filter": "datum.app != null"}
  ],
  "encoding": {
    "color": {"type": "nominal", "field": "app"},
    "x": {"type": "quantitative", "field": "timestamp"},
    "x2": {"type": "quantitative", "field": "t_stop"},
    "y": {
      "type": "nominal",
      "field": "state",
      "sort": {"op": "sum", "field": "timestamp", "order": "ascending"}
    }
  },
  "mark": "bar",
  "$schema": "https://vega.github.io/schema/vega-lite/v2.6.0.json"
}