From 443cb1085bdaf526b2a10dfa85dfba540a1617b7 Mon Sep 17 00:00:00 2001
From: asahi <mikiyashiki@outlook.com>
Date: Wed, 25 Dec 2024 12:55:27 +0800
Subject: [PATCH] =?UTF-8?q?=E9=98=85=E8=AF=BBes=E6=96=87=E6=A1=A3?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 elastic search/elastic search.md | 89 ++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/elastic search/elastic search.md b/elastic search/elastic search.md
index 1df71f0..61a4c3b 100644
--- a/elastic search/elastic search.md	
+++ b/elastic search/elastic search.md	
@@ -611,6 +611,95 @@ PUT /cooking_blog/_mapping
 > 
 > 当`ignore_above`没有显式指定时，其值默认为256.
 
+#### 批量插入数据
+再创建索引后，可以向索引中批量插入文档数据：
+```
+POST /cooking_blog/_bulk?refresh=wait_for
+{"index":{"_id":"1"}}
+{"title":"Perfect Pancakes: A Fluffy Breakfast Delight","description":"Learn the secrets to making the fluffiest pancakes, so amazing you won't believe your tastebuds. This recipe uses buttermilk and a special folding technique to create light, airy pancakes that are perfect for lazy Sunday mornings.","author":"Maria Rodriguez","date":"2023-05-01","category":"Breakfast","tags":["pancakes","breakfast","easy recipes"],"rating":4.8}
+{"index":{"_id":"2"}}
+{"title":"Spicy Thai Green Curry: A Vegetarian Adventure","description":"Dive into the flavors of Thailand with this vibrant green curry. Packed with vegetables and aromatic herbs, this dish is both healthy and satisfying. Don't worry about the heat - you can easily adjust the spice level to your liking.","author":"Liam Chen","date":"2023-05-05","category":"Main Course","tags":["thai","vegetarian","curry","spicy"],"rating":4.6}
+{"index":{"_id":"3"}}
+{"title":"Classic Beef Stroganoff: A Creamy Comfort Food","description":"Indulge in this rich and creamy beef stroganoff. Tender strips of beef in a savory mushroom sauce, served over a bed of egg noodles. It's the ultimate comfort food for chilly evenings.","author":"Emma Watson","date":"2023-05-10","category":"Main Course","tags":["beef","pasta","comfort food"],"rating":4.7}
+{"index":{"_id":"4"}}
+{"title":"Vegan Chocolate Avocado Mousse","description":"Discover the magic of avocado in this rich, vegan chocolate mousse. Creamy, indulgent, and secretly healthy, it's the perfect guilt-free dessert for chocolate lovers.","author":"Alex Green","date":"2023-05-15","category":"Dessert","tags":["vegan","chocolate","avocado","healthy dessert"],"rating":4.5}
+{"index":{"_id":"5"}}
+{"title":"Crispy Oven-Fried Chicken","description":"Get that perfect crunch without the deep fryer! This oven-fried chicken recipe delivers crispy, juicy results every time. A healthier take on the classic comfort food.","author":"Maria Rodriguez","date":"2023-05-20","category":"Main Course","tags":["chicken","oven-fried","healthy"],"rating":4.9}
+```
+
+#### 执行full-text search 
+full-text search会在一个或多个document fields之间执行基于文本的查询。这些查询会为每个匹配的文档计算relevance score，relevance score的计算基于文档内容和search terms的关联程度。
+
+ES支持多种查询类型，每种查询类型都有其`matching text`和`relevance scoring`的方法。
+
+##### `match`
+match是针对full-text的标准查询，基于每个字段上配置的analyzer，query text将会被分析。
+
+```
+GET /cooking_blog/_search
+{
+  "query": {
+    "match": {
+      "description": {
+        "query": "fluffy pancakes" 
+      }
+    }
+  }
+}
+```
+默认情况下，`match query`在resulting tokens间使用`or`，故而在上述的查询中，会查找description中包含`fluffy`或`pancakes`任一的document。
+
+其会返回结果如下：
+```
+{
+  "took": 0,
+  "timed_out": false,
+  "_shards": {
+    "total": 1,
+    "successful": 1,
+    "skipped": 0,
+    "failed": 0
+  },
+  "hits": { 
+    "total": {
+      "value": 1,
+      "relation": "eq"
+    },
+    "max_score": 1.8378843, 
+    "hits": [
+      {
+        "_index": "cooking_blog",
+        "_id": "1",
+        "_score": 1.8378843, 
+        "_source": {
+          "title": "Perfect Pancakes: A Fluffy Breakfast Delight", 
+          "description": "Learn the secrets to making the fluffiest pancakes, so amazing you won't believe your tastebuds. This recipe uses buttermilk and a special folding technique to create light, airy pancakes that are perfect for lazy Sunday mornings.", 
+          "author": "Maria Rodriguez",
+          "date": "2023-05-01",
+          "category": "Breakfast",
+          "tags": [
+            "pancakes",
+            "breakfast",
+            "easy recipes"
+          ],
+          "rating": 4.8
+        }
+      }
+    ]
+  }
+}
+```
+
+> ##### track total hits
+> 如果想要精确计算hit count，通常需要遍历所有的匹配文档，这将会带来很大开销。
+>
+> `track_total_hists`参数允许对`如何计算hit count`进行控制。
+> - 如果设置为true，那么会精确的计算匹配数量，`total.relation`会一直为`eq`，代表`total.value`和实际hit count相同
+> - 如果该值为其他值，例如其默认值`10000`，则该查询数量的`下限`为`10000`
+>   - 如果`total.relation`为`eq`，则`total.value`代表实际hit count
+>   - 如果`total.relation`为`gte`， 则`total.value`为hit count的下界，实际hit count大于或等于`total.value`
+
+