Elasticsearch核心知识篇(65)
索引管理_定制化自己的dynamic mapping策略
定制dynamic策略
- true：遇到陌生字段，就进行dynamic mapping
- false：遇到陌生字段，就忽略
- strict：遇到陌生字段，就报错
PUT /my_index
{
"mappings": {
"my_type": {
"dynamic": "strict",
"properties": {
"title": {
"type": "text"
},
"address": {
"type": "object",
"dynamic": "true"
}
}
}
}
}
- 示例数据
PUT /my_index/my_type/1
{
"title": "my article",
"content": "this is my article", # 没见过的字段
"address": {
"province": "guangdong",
"city": "guangzhou"
}
}
{
"error": {
"root_cause": [
{
"type": "strict_dynamic_mapping_exception",
"reason": "mapping set to strict, dynamic introduction of [content] within [my_type] is not allowed"
}
],
"type": "strict_dynamic_mapping_exception",
"reason": "mapping set to strict, dynamic introduction of [content] within [my_type] is not allowed"
},
"status": 400
}
PUT /my_index/my_type/1
{
"title": "my article",
"address": {
"province": "guangdong",
"city": "guangzhou"
}
}
{
"_index": "my_index",
"_type": "my_type",
"_id": "1",
"_version": 1,
"result": "created",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"created": true
}
- 查看数据
GET /my_index/_mapping/my_type
{
"my_index": {
"mappings": {
"my_type": {
"dynamic": "strict",
"properties": {
"address": {
"dynamic": "true",
"properties": {
"city": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"province": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
},
"title": {
"type": "text"
}
}
}
}
}
}
定制dynamic mapping策略
- date_detection
默认会按照一定格式识别date，比如yyyy-MM-dd。但是如果某个field先过来一个2017-01-01的值，就会被自动dynamic mapping成date，后面如果再来一个"hello world"之类的值，就会报错。可以手动关闭某个type的date_detection，如果有需要，自己手动指定某个field为date类型。
PUT /my_index/_mapping/my_type
{
"date_detection": false
}
- 定制自己的dynamic mapping template（type level）
PUT /my_index
{
"mappings": {
"my_type": {
"dynamic_templates": [
{ "en": {
"match": "*_en",
"match_mapping_type": "string",
"mapping": {
"type": "string",
"analyzer": "english"
}
}}
]
}}}
- 示例数据
PUT /my_index/my_type/1
{
"title": "this is my first article"
}
PUT /my_index/my_type/2
{
"title_en": "this is my first article"
}
GET /my_index/_mapping/my_type
{
"my_index": {
"mappings": {
"my_type": {
"dynamic_templates": [
{
"en": {
"match": "*_en",
"match_mapping_type": "string",
"mapping": {
"analyzer": "english",
"type": "string"
}
}
}
],
"properties": {
"title": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"title_en": {
"type": "text",
"analyzer": "english"
}
}
}
}
}
}
GET /my_index/my_type/_search
{
"query":{
"match":{
"title":"is"
}
}
}
{
"took": 1,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 1,
"max_score": 0.2824934,
"hits": [
{
"_index": "my_index",
"_type": "my_type",
"_id": "1",
"_score": 0.2824934,
"_source": {
"title": "this is my first article"
}
}
]
}
}
title没有匹配到任何的dynamic模板，默认就是standard分词器，不会过滤停用词，is会进入倒排索引，用is来搜索是可以搜索到的
title_en匹配到了dynamic模板，就是english分词器，会过滤停用词，is这种停用词就会被过滤掉，用is来搜索就搜索不到了
- 定制自己的default mapping template（index level）
PUT /my_index
{
"mappings": {
"_default_": {
"_all": { "enabled": false }
},
"blog": {
"_all": { "enabled": true }
}
}
}
Elasticsearch核心知识篇(66)
索引管理_复杂上机实验：基于scoll+bulk+索引别名实现零停机重建索引
重建索引
一个field的设置是不能被修改的，如果要修改一个Field，那么应该重新按照新的mapping，建立一个index，然后将数据批量查询出来，重新用bulk api写入index中
批量查询的时候，建议采用scroll api，并且采用多线程并发的方式来reindex数据，每次scoll就查询指定日期的一段数据，交给一个线程即可
- 一开始，依靠dynamic mapping，插入数据，但是不小心有些数据是2017-01-01这种日期格式的，所以title这种field被自动映射为了date类型，实际上它应该是string类型的
PUT /my_index/my_type/3
{
"title": "2017-01-03"
}
{
"my_index": {
"mappings": {
"my_type": {
"properties": {
"title": {
"type": "date"
}
}
}
}
}
}
- 当后期向索引中加入string类型的title值的时候，就会报错
PUT /my_index/my_type/4
{
"title": "my first article"
}
{
"error": {
"root_cause": [
{
"type": "mapper_parsing_exception",
"reason": "failed to parse [title]"
}
],
"type": "mapper_parsing_exception",
"reason": "failed to parse [title]",
"caused_by": {
"type": "illegal_argument_exception",
"reason": "Invalid format: "my first article""
}
},
"status": 400
}
- 如果此时想修改title的类型，是不可能的
PUT /my_index/_mapping/my_type
{
"properties": {
"title": {
"type": "text"
}
}
}
{
"error": {
"root_cause": [
{
"type": "illegal_argument_exception",
"reason": "mapper [title] of different type, current_type [date], merged_type [text]"
}
],
"type": "illegal_argument_exception",
"reason": "mapper [title] of different type, current_type [date], merged_type [text]"
},
"status": 400
}
-
此时，唯一的办法，就是进行reindex，也就是说，重新建立一个索引，将旧索引的数据查询出来，再导入新索引
-
如果说旧索引的名字，是old_index，新索引的名字是new_index，终端java应用，已经在使用old_index在操作了，难道还要去停止java应用，修改使用的index为new_index，才重新启动java应用吗？这个过程中，就会导致java应用停机，可用性降低
-
所以说，给java应用一个别名，这个别名是指向旧索引的，java应用先用着，java应用先用goods_index alias来操作，此时实际指向的是旧的my_index
PUT /my_index/_alias/goods_index
- 新建一个index，调整其title的类型为string
PUT /my_index_new
{
"mappings": {
"my_type": {
"properties": {
"title": {
"type": "text"
}
}
}
}
}
- 使用scroll api将数据批量查询出来
GET /my_index/_search?scroll=1m
{
"query": {
"match_all": {}
},
"sort": ["_doc"],
"size": 1
}
{
"_scroll_id": "DnF1ZXJ5VGhlbkZldGNoBQAAAAAAADpAFjRvbnNUWVZaVGpHdklqOV9zcFd6MncAAAAAAAA6QRY0b25zVFlWWlRqR3ZJajlfc3BXejJ3AAAAAAAAOkIWNG9uc1RZVlpUakd2SWo5X3NwV3oydwAAAAAAADpDFjRvbnNUWVZaVGpHdklqOV9zcFd6MncAAAAAAAA6RBY0b25zVFlWWlRqR3ZJajlfc3BXejJ3",
"took": 1,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 3,
"max_score": null,
"hits": [
{
"_index": "my_index",
"_type": "my_type",
"_id": "2",
"_score": null,
"_source": {
"title": "2017-01-02"
},
"sort": [
0
]
}
]
}
}
- 采用bulk api将scoll查出来的一批数据，批量写入新索引
POST /_bulk
{ "index": { "_index": "my_index_new", "_type": "my_type", "_id": "2" }}
{ "title": "2017-01-02" }
-
反复循环8~9，查询一批又一批的数据出来，采取bulk api将每一批数据批量写入新索引
-
将goods_index alias切换到my_index_new上去，java应用会直接通过index别名使用新的索引中的数据，java应用程序不需要停机，零提交，高可用
POST /_aliases
{
"actions": [
{ "remove": { "index": "my_index", "alias": "goods_index" }},
{ "add": { "index": "my_index_new", "alias": "goods_index" }}
]
}
- 直接通过goods_index别名来查询，是否ok
GET /goods_index/my_type/_search
基于alias对client透明切换index
PUT /my_index_v1/_alias/my_index
client对my_index进行操作
reindex操作，完成之后，切换v1到v2
POST /_aliases
{
"actions": [
{ "remove": { "index": "my_index_v1", "alias": "my_index" }},
{ "add": { "index": "my_index_v2", "alias": "my_index" }}
]
}
