fields 自定义返回字段
{
//"_source": false,
//"_source": ["aa*", "bb*"]
//"_source": ["username"]
"fields": ["username"],
"aggs" : {
"genders" : {
"terms" : { "field": "username" }
}
}
}基于时间范围的分类汇总
{
//select yearmon(createtime) yearmon,method,status,count(*)
// from test group by yearmon,method,status
"size": 0,
"aggs" : {
"day_total" : {
"date_histogram":{
"field": "CreateTime",
"interval": "day",
"format": "yyyyMMdd"
},
"aggs": {
"method_total":{
"terms": {"field": "method"},
"aggs":{
"status_total":{
"terms": {"field": "status"}
}
}
}
}
}
}
}Date detectionedit
If date_detection is enabled (default), then new string fields are checked to see whether their contents match any of the date patterns specified in dynamic_date_formats. If a match is found, a new date field is added with the corresponding format.
The default value for dynamic_date_formats is:
[“strict_date_optional_time”,”yyyy/MM/dd HH:mm:ss Z||yyyy/MM/dd Z”]
For example:
PUT my_index/my_type/1
{
"create_date": "2015/09/02"
}
GET my_index/_mapping The create_date field has been added as a date field with the format: “yyyy/MM/dd HH:mm:ss Z||yyyy/MM/dd Z”.
Disabling date detectionedit
Dynamic date dection can be disabled by setting date_detection to false:
PUT my_index
{
"mappings": {
"my_type": {
"date_detection": false
}
}
}
PUT my_index/my_type/1
{
"create": "2015/09/02"
}The create_date field has been added as a string field.
Customising detected date formatsedit
Alternatively, the dynamic_date_formats can be customised to support your own date formats:
PUT my_index
{
"mappings": {
"my_type": {
"dynamic_date_formats": ["MM/dd/yyyy"]
}
}
}
PUT my_index/my_type/1
{
"create_date": "09/25/2015"
}Disabling automatic type creationedit
Automatic type creation can be disabled by setting the index.mapper.dynamic setting to false, either by setting the default value in the config/elasticsearch.yml file, or per-index as an index setting:
PUT /_settings
{
"index.mapper.dynamic":false
}强制清除Elasticsearch中已删除的文件
POST /_optimize?only_expunge_deletes=true下面两个设置可以用于控制清除时的处理速度，其中给出值是默认值，可以根据需求进行调整，具体请参见 Merge。 此外， 还可以临时将所有索引的replica设置为0，这样只用针对Primary进行expunge，以减小I/O压力。
PUT /{index}/_settings
{
"settings": {
"index.merge.policy.expunge_deletes_allowed": "10",
"index.merge.policy.max_merge_at_once_explicit" : "30"
}
}检查文档是否存在
如果你想做的只是检查文档是否存在——你对内容完全不感兴趣——使用 HEAD 方法来代替 GET 。 HEAD 请求不会返回响应
体，只有HTTP头：
curl -i -XHEAD http://localhost:9200/website/blog/123
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8
Content-Length: 0
curl -i -XHEAD http://localhost:9200/website/blog/124
HTTP/1.1 404 Not Found
Content-Type: text/plain; charset=UTF-8
Content-Length: 0该API同样也适合于检查index,type是否存在
Elasticsearch权威指南精华章节
官方API接口文档收集
内存性能优化方面
限制内存使用
https://www.elastic.co/guide/en/elasticsearch/guide/current/_limiting_memory_usage.htmlfielddata说明
https://www.elastic.co/guide/en/elasticsearch/reference/2.0/fielddata.html预热fielddata
https://www.elastic.co/guide/en/elasticsearch/guide/current/preload-fielddata.html优化索引性能技巧
https://www.elastic.co/guide/en/elasticsearch/guide/current/indexing-performance.htmlDoc_values使用
https://www.elastic.co/guide/en/elasticsearch/guide/current/doc-values.html
Index模块
- Index模块之stroe
https://www.elastic.co/guide/en/elasticsearch/reference/1.7/index-modules-store.html - Index模块之translog
https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules-translog.html - Index模块之merge
https://www.elastic.co/guide/en/elasticsearch/reference/1.7/index-modules-merge.html - Index Settings
https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules.html#index-modules-settings - Shard Allocation Filtering
https://www.elastic.co/guide/en/elasticsearch/reference/current/shard-allocation-filtering.html
Cluster模块
- https://www.elastic.co/guide/en/elasticsearch/reference/2.1/modules-cluster.html
- Cluster Level Shard Allocation Cluster Level Shard Allocation lists the settings to control the allocation an rebalancing operations.
- Disk-based Shard Allocation explains how Elasticsearch takes available disk space into account, and the related settings.
- Shard Allocation Awareness Shard Allocation Awareness control how shards can be distributed across different racks or availability zones.
Shard Allocation Filtering Shard Allocation Filtering allows certain nodes or groups of nodes excluded from allocation so that they can be decommisioned.
Cluster Reroute The reroute command allows to explicitly execute a cluster reroute allocation command including specific commands.
API接口
连接查询
https://www.elastic.co/guide/en/elasticsearch/reference/2.1/joining-queries.htmlbulk api
https://www.elastic.co/guide/en/elasticsearch/reference/2.1/docs-bulk.htmlindex api
https://www.elastic.co/guide/en/elasticsearch/reference/2.1/docs-index_.htmlupdate api
https://www.elastic.co/guide/en/elasticsearch/reference/1.7/docs-update.html搜索偏好（search preference）
https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-preference.html分布式存储
https://www.elastic.co/guide/en/elasticsearch/guide/current/distributed-docs.html
分布式搜索
https://www.elastic.co/guide/en/elasticsearch/guide/master/distributed-search.htmlCluster Update Settings
https://www.elastic.co/guide/en/elasticsearch/reference/1.7/cluster-update-settings.html_cat API
https://www.elastic.co/guide/en/elasticsearch/reference/2.2/cat-nodes.html
其它
脚本模块
https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-scripting.html选项参数
https://www.elastic.co/guide/en/elasticsearch/reference/2.1/common-options.html