Setting Up Elasticsearch Index Mappings and Index Templates скачать в хорошем качестве

Setting Up Elasticsearch Index Mappings and Index Templates

This video runs you through setting up Elasticsearch index mappings and index templates, using the dev tools console in Kibana. This is a simple and quick way to submit http requests to elasticsearch, as you will see in the video it provides auto complete on the URLs and the json payload which is really handy. Setting Up an Elasticsearch Index Mapping If you don't provide a index mapping elasticsearch will guess one for you. Generally the default mapping will meet most of your requirements. However there are a few good reasons to setup an index mapping firstly its likely you can save a lot of storage space and it ensures that elastic does not guess the wrong type (which could mean most of your data gets rejects) - this can happen when you have a text field that sometimes contains a date. Lets see elasticsearch guessing in action - by posting a document into elasticsearch with no mapping preset. POST /transactions/_doc/1 { "amount": "6836.40", "direction": "in", "reference": "1031754877274", "submittedDatetime": "26/01/2020", "processedDatetime" : "2020-01-26T22:02:35+10:00", "description": "Payment for invoice #123222" } Now view the document to confirm it has been created GET transactions/_search Now lets review the mapping that got created (basically elasticsearch's guesses based on the first document that we loaded into the index) GET /transactions As you can see it mostly created all the fields as multi type - text and keyword. However that is not really what we want: Amount has been indexed as text and keyword - we need it indexed as double direction has been indexed as text and keyword - we only need keyword - as its a categorial value in our system. reference has been indexed as text and keyword - we need long as it is a long number submittedDatetime has been indexed as text and keyword - we need date Description should be text - cause we want to support free text search but we don't need keyword for aggregrations. So lets setup the mapping we want PUT transactions/ { "mappings": { "properties": { "amount": { "type": "double" }, "description": { "type": "text" }, "direction": { "type": "keyword" }, "processedDatetime": { "type": "date" }, "reference": { "type": "long" }, "submittedDatetime": { "type": "date", "format": "dd/MM/yyyy" } } } } Key lesson to remember is that mappings can not changed once the index is created. You can add additional fields. However you can NOT change the type of an existing field. So we need to delete our index to start again. DELETE transactions Now we post in our document again POST /transactions/_doc/1 { "amount": "6836.40", "direction": "in", "reference": "1031754877274", "submittedDatetime": "26/01/2020", "processedDatetime" : "2020-01-26T22:02:35+10:00", "description": "Payment for invoice #123222" } We can check the mappings have been applied correctly GET transactions We can now search using these mappings GET /transactions/_search?q=submittedDatetime:[25/01/2020 TO 26/01/2020] Ok so our mapping is working. Best practice is to create an index template that sits in the background and waits for an index to be created with a specifc index pattern and applies our template. Here is how we do that PUT _index_template/transaction_template { "index_patterns": [ "transaction*" ], "template": { "settings": { "number_of_shards": 2 }, "mappings": { "properties": { "amount": { "type": "double" }, "description": { "type": "text" }, "direction": { "type": "keyword" }, "processedDatetime": { "type": "date" }, "reference": { "type": "long" }, "submittedDatetime": { "type": "date", "format": "dd/MM/yyyy" } } } } } So we need to delete our index to start again. DELETE transactions Now we post in our document again the index is created but it uses the index template for the mappings and settings POST /transactions/_doc/1 { "amount": "6836.40", "direction": "in", "reference": "1031754877274", "submittedDatetime": "26/01/2020", "processedDatetime" : "2020-01-26T22:02:35+10:00", "description": "Payment for invoice #123222" } GET transactions