From b68a7feebf4f29bbeaa714fbc8d9c9ac842451f6 Mon Sep 17 00:00:00 2001
From: liujianhuan <liujianhuan@qianxin.com>
Date: Mon, 11 Jan 2021 18:38:32 +0800
Subject: [PATCH] scan part-1

---
 Querying/scan.md | 115 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 114 insertions(+), 1 deletion(-)

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+<!-- toc -->
+## Scan查询
+
+> [!WARNING]
+> Apache Druid支持两种查询语言： [Druid SQL](druidsql.md) 和 [原生查询](makeNativeQueries.md)。该文档描述了原生查询中的一种查询方式。 对于Druid SQL中使用的该种类型的信息，可以参考 [SQL文档](druidsql.md)。
+
+Scan查询以流模式返回原始Apache Druid行。
+
+除了向Broker发出扫描查询的简单用法之外，还可以直接向Historical或流式摄取任务发出扫描查询。如果您希望并行地检索大量数据，这将非常有用。
+
+扫描查询对象示例如下所示：
+
+```json
+ {
+   "queryType": "scan",
+   "dataSource": "wikipedia",
+   "resultFormat": "list",
+   "columns":[],
+   "intervals": [
+     "2013-01-01/2013-01-02"
+   ],
+   "batchSize":20480,
+   "limit":3
+ }
+ ```
+
+ 以下为Scan查询的主要参数：
+
+ | 属性 | 描述 | 是否必须 |
+ |-|-|-|
+ | `queryType` | | 是 |
+ | `dataSource` || 是 |
+ | `intervals` || 是 |
+ | `resultFormat` || 否 |
+ | `filter` || 否 |
+ | `columns` || 否 |
+ | `batchSize` || 否 |
+ | `limit` || 否 |
+ | `offset` || 否 |
+ | `order` || NONE |
+ | `legacy` || 否 |
+ | `context` || 否 |
+
+ ### 示例结果
+
+当resultFormat为 `list`时，结果格式如下：
+
+ ```json
+  [{
+    "segmentId" : "wikipedia_editstream_2012-12-29T00:00:00.000Z_2013-01-10T08:00:00.000Z_2013-01-10T08:13:47.830Z_v9",
+    "columns" : [
+      "timestamp",
+      "robot",
+      "namespace",
+      "anonymous",
+      "unpatrolled",
+      "page",
+      "language",
+      "newpage",
+      "user",
+      "count",
+      "added",
+      "delta",
+      "variation",
+      "deleted"
+    ],
+    "events" : [ {
+        "timestamp" : "2013-01-01T00:00:00.000Z",
+        "robot" : "1",
+        "namespace" : "article",
+        "anonymous" : "0",
+        "unpatrolled" : "0",
+        "page" : "11._korpus_(NOVJ)",
+        "language" : "sl",
+        "newpage" : "0",
+        "user" : "EmausBot",
+        "count" : 1.0,
+        "added" : 39.0,
+        "delta" : 39.0,
+        "variation" : 39.0,
+        "deleted" : 0.0
+    }, {
+        "timestamp" : "2013-01-01T00:00:00.000Z",
+        "robot" : "0",
+        "namespace" : "article",
+        "anonymous" : "0",
+        "unpatrolled" : "0",
+        "page" : "112_U.S._580",
+        "language" : "en",
+        "newpage" : "1",
+        "user" : "MZMcBride",
+        "count" : 1.0,
+        "added" : 70.0,
+        "delta" : 70.0,
+        "variation" : 70.0,
+        "deleted" : 0.0
+    }, {
+        "timestamp" : "2013-01-01T00:00:00.000Z",
+        "robot" : "0",
+        "namespace" : "article",
+        "anonymous" : "0",
+        "unpatrolled" : "0",
+        "page" : "113_U.S._243",
+        "language" : "en",
+        "newpage" : "1",
+        "user" : "MZMcBride",
+        "count" : 1.0,
+        "added" : 77.0,
+        "delta" : 77.0,
+        "variation" : 77.0,
+        "deleted" : 0.0
+    } ]
+} ]
+```
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