Video learning link ：https://www.bilibili.com/video/BV1hh411D7sb

Basic knowledge of

Elastic search：

• Open source highly extended distributed full-text search engine , Whole ES The core of the technology stack .
• Near real-time storage 、 Retrieving data
• Good scalability , Scalable to hundreds of servers , Handle PB Level of data
• be based on Lucene Development （Lucene It provides the ability of Full-text Retrieval , But there is no way to use it directly ）

introduction （mac edition ）

Official website download address ：https://www.elastic.co/cn/downloads/elasticsearch

1. start-up ：

   Enter the directory through the terminal elasticsearch-7.13.2/bin Next , perform command sh elasticsearch perhaps ./elasticsearch, You can start successfully
   

   Partial startup log
   

​ The result of browser access in the figure indicates that the startup is successful （ Be careful not to start repeatedly ）：

2. stop it

   You can kill the process number , stop it es

   ps -ef ｜grep elastic

   kill -9 93467

3. http Way to use ES

   Grammar official use document ：https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html?baymax=rec&rogue=pop-1&elektra=docs

   Use postman establish

   An index is equivalent to a database , Document is equivalent to table

   action	Request mode	Address	Parameters	Idempotency	remarks
   Create index	PUT	http://127.0.0.1:9200/shopping		Y
   Look at the index	GET	http://127.0.0.1:9200/shopping		Y
   Delete index	DELETE	http://127.0.0.1:9200/shopping		Y
   View all indexes	GET	http://127.0.0.1:9200/_cat/indices?v		Y
   Create documents under the index	POST	http://127.0.0.1:9200/shopping/_doc	{“name”:“ Mi phones ”,“category”:“ millet ”,“price”:1000.00}	N	The same document can be stored multiple times , Each response id Different
   Create documents under the index （ Customize id）	POST	http://127.0.0.1:9200/shopping/_doc/1001	{“name”:“ Mi phones ”,“category”:“ millet ”,“price”:1000.00}	N	PUT It's fine too （ The request for many times id unchanged , however version Will change , Similar to modifying the content ）
   obtain shoping All the data below	GET	http://127.0.0.1:9200/shopping/_search		Y
   Completely modify the data	PUT	http://127.0.0.1:9200/shopping/_doc/1001	{“name”:“ Mi phones ”,“category”:“ millet ”,“price”:4000.00}	N
   Modify some data	POST	http://127.0.0.1:9200/shopping/_update/1001	{“doc”:{“name”:“ Huawei mobile phones ”}}	Y	Ask many times version No increase
   Conditions of the query	GET	http://127.0.0.1:9200/shopping/_search?q=category: millet			Path parameters
   Conditions of the query	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“match”:{“category”:“ millet ”}}}		Request body spelling parameters
   Paging query	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“match_all”:{}},“from”:0,“size”:2}		from： Page number , Calculation formula ：（ Page number -1）* Number of data bars per page ;size： Number of data bars per page
   Inquire about ： Specify the display content	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“match_all”:{}},“from”:0,“size”:2,"_source":[“name”,“price”]}
   Sort query	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“match_all”:{}},"_source":[“name”,“price”],“sort”:{“price”:{“order”:“asc”}}}		The sort price must be Numbers
   Link query and	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“bool”:{“must”:[{“match”:{ “category”:“ millet ”}},{“match”:{“price”:1000.00}}]}}}		must
   Link query or	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“bool”:{“should”:[{“match”:{ “category”:“ millet ”}},{“match”:{“price”:1000.00}}]}}}		should
   Range queries	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“bool”:{“should”:[{“match”:{ “category”:“ millet ”}},{“match”:{“price”:1000.00}}],“filter”:{“range”:{“price”:{“gt”:4000.00}}}}}}		filter
   Full text keyword search	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“match_phrase”:{“category”:“ millet ”}}}		Keyword search , No word segmentation for query conditions
   The search results are highlighted	GET	http://127.0.0.1:9200/shopping/_search	{“query”:{“match_phrase”:{“category”:“ millet ”}},“highlight”:{“fields”:{“category”:{}}}}		The return result increases html style
   Aggregate query ： grouping			{“aggs”:{“price_group”:{“terms”:{“field”:“price”}}}}		aggs Represents an aggregate query ;price_group Group name Customize ;terms grouping . The results are grouped by field
   Aggregate query ： Average			{“aggs”:{“price_avg”:{“avg”:{“field”:“price”}}}}		avg Average the fields
   http Create index mapping			{“properties”:{“name”:{“type”:“text”,“index”:true},“sex”:{“type”:“keyword”,“index”:true},“tel”:{“type”:“keyword”,“index”:false}}}		properties Index configuration ;name Document fields ;type：“text” Field type ;index Whether to create an index for this field ;keyword keyword , That is, no word segmentation is done for this attribute