Shulou(Shulou.com)06/03 Report--

Core data type text & keywordText: 1: supports word segmentation, full-text search, fuzzy and precise query, but does not support aggregation and sorting operations; 2:test type supports unlimited character length, suitable for large field storage; use scenarios: store full-text search data, such as email content, address, code block, blog article content, etc. By default, combined with standard analyzer (standard parser), the text is segmented and inverted. By default, the standard analyzer is used to score the word hit and word frequency correlation. Keyword:1: no word segmentation, direct indexing, support for fuzzy, support for exact matching, support for aggregation, sorting operations. The maximum length of 2:keyword type is-32766 characters of UTF-8 type. You can specify the self-supporting character length by setting ignore_above. The data beyond the given length will not be indexed, and the returned results cannot be retrieved through term exact matching. Usage scenarios: store mailbox number, url, name, title, mobile phone number, hostname, status code, zip code, label, age, gender and other data. Used to filter data (for example: select * from x where status='open'), sort, aggregate (statistics). Save the complete text directly to the inverted index. The Mapping parameter indexindex defines the analysis type and retrieval method of the field, and controls whether the field value is indexed. It can be set to true or false. Not indexed field will not be able to search if it is no, then can not query the field through retrieval; if set to not_analyzed, the entire field will be stored as keywords, often used for Chinese phrases, mailboxes and other complex strings; if set to analyzed, the Dynamicdynamic property will be analyzed through the default standard parser: the default value is true, allowing dynamic addition of new fields to the document type. The recommended setting is false, which forbids the addition of fields to the document, so that all fields of the document type must be explicitly defined in the properties property of the index map, and fields not defined in the properties field will be ignored by ElasticSearch. Dynamic is set to ture: default, newly added fields are added to the index mapping; dynamic is set to false: newly added fields are ignored; dynamic is set to strict: when new fields are added to the document, the ElasticSearch engine throws an exception; cluster shard Elasticsearch has a hard-coding limit, and the total number of documents in a single shard cannot exceed 2147483519. Generally speaking, this restriction is not likely to be triggered in log scenarios, but if you use it for TSDB, you need to pay more attention to it!

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