1.6 Elasticsearch Analyzer

1. What Is an Analyzer?

Split a sentence into individual words and perform normalization on each word.

1.1. Recall

Increase the number of results that can be found during search.

2. Components of an Analyzer

2.1. character filter

Preprocess a piece of text before tokenization. Common examples include filtering HTML tags (<span>hello<span> –> hello) and converting & to and (I&you –> I and you).

2.2. tokenizer

Tokenization: hello you and me –> hello, you, and, me.

2.3. token filter

lowercase, stop word, synonym: dogs –> dog, liked –> like, Tom –> tom, a/the/an –> removed, mother –> mom, small –> little.

3. Install IK Analyzer

• Download https://github.com/medcl/elasticsearch-analysis-ik/releases/download/v7.4.2/elasticsearch-analysis-ik-7.4.2.zip
• Extract it under elasticsearch-5.2.0\plugin\ik.
• Restart ES.

4. References

• GitHub - medcl/elasticsearch-analysis-ik: The IK Analysis plugin integrates Lucene IK analyzer into elasticsearch, support customized dictionary.