script_score介绍

在Elasticsearch中，script_score是在function_score查询中的一种功能强大的方式，允许用户使用内置Painless脚本语言或者其他支持的语言来动态计算每个文档的评分

script_score语法

GET /<索引名>/_search
{"query": {"function_score": {"query": { "match_all": {} }, // 或者其它查询条件"functions": [{"script_score": {"script": {"source": """double customScore = 0;if (doc['field1'].value > params.threshold1) {customScore += doc['field1'].value * params.multiplier1;}customScore += doc['field2'].value;return customScore;""","params": {"threshold1": 50,"multiplier1": 0.5}}}}],"score_mode": "sum", // 或者其它score_mode"boost_mode": "replace" // 或者其它boost_mode}}
}

• script_score被用来定义一个脚本，该脚本计算文档的自定义评分
• source字段内是Painless脚本，它可以访问文档中的字段值（如doc[‘field1’].value和doc[‘field2’].value）并对它们进行计算
• params是一个键值对对象，用于传递给脚本的参数，此处定义了两个参数：threshold1和multiplier1

script_score 案例

场景

假设我们有一个问答论坛索引，需要基于回答数量和点赞数查找高质量

索引创建

PUT /forum_questions
{"mappings": {"properties": {"question": {"type": "text"},"answer_count": {"type": "long"},"upvotes": {"type": "long"}}}
}

文档插入

POST /forum_questions/_doc/
{"question": "What is Elasticsearch?","answer_count": 5,"upvotes": 20
}POST /forum_questions/_doc/
{"question": "How to configure Elasticsearch for production?","answer_count": 3,"upvotes": 15
}POST /forum_questions/_doc/
{"question": "Best practices for indexing data in Elasticsearch?","answer_count": 10,"upvotes": 30
}POST /forum_questions/_doc/
{"question": "How to optimize Elasticsearch performance?","answer_count": 8,"upvotes": 18
}POST /forum_questions/_doc/
{"question": "What are shards and replicas in Elasticsearch?","answer_count": 6,"upvotes": 25
}POST /forum_questions/_doc/
{"question": "How to handle time-based data in Elasticsearch?","answer_count": 4,"upvotes": 12
}POST /forum_questions/_doc/
{"question": "What is the difference between match and term queries?","answer_count": 7,"upvotes": 23
}POST /forum_questions/_doc/
{"question": "How to set up Elasticsearch clusters?","answer_count": 9,"upvotes": 16
}

查询

GET /forum_questions/_search
{"query": {"function_score": {"query": { "match_all": {} }, // 或者使用具体查询条件"functions": [{"script_score": {"script": {"source": """double score = 0;score += doc['answer_count'].value * params.answer_weight;score += doc['upvotes'].value * params.upvote_weight;return score;""","params": {"answer_weight": 0.7,"upvote_weight": 0.3}}}}],"score_mode": "sum"}}
}