Elasticsearch function_score查询格式错误排查求助

错误信息 #

"type":"parsing_exception",
"reason":"[function_score] malformed query, expected [END_OBJECT] but found [FIELD_NAME]"

问题描述 #

原本有一段可正常运行的PHP Elasticsearch查询代码，想要添加function_score功能，基于tstamp字段给近期内容提升权重。添加代码后出现上述解析错误。

错误的完整查询代码 #

'query' => [
    'function_score' => [
        'functions' => [
            [
                'filter'=> [
                    'range' => [
                        'tstamp' => [
                            'gte' => 'now-1y',
                            'lte'  => 'now'
                        ]
                    ]
                ],
                'weight' => 5
            ],
            [
                'filter' => [
                    'range' => [
                        'tstamp' => [
                            'gte' => 'now-3yr',
                            'lte' => 'now-1yr'
                        ]
                    ]
                ],
                'weight' => 2
            ]
        ],
        'boost_mode' => 'multiply'
    ],
    'bool' => [
        'filter' => [
            ['range' => [
                'starttime' => ['lte' => $now],
            ]]
        ],
        'must' => [
            ["multi_match" => [
                'fuzziness' =>  'auto',
                'query' => $_REQUEST['kw'],
                'fields' => [
                    'content^2',
                    'teaser^2',
                    'bodytext^2',
                    'title^5',
                    'header^3'
                ],
            ]],
            ['bool' => [
                'should' => [
                    ['match' => ['sys_language_uid' =>  $sysLanguageUid]],
                    ['match' => ['sys_language_uid' => -1]],
                ],
                'minimum_should_match' => 1,
            ]],
        ],
        'must_not' => [
            ['match' => ['hidden' => 1]],
            ['match' => ['deleted' => 1]],
            ['match' => ['no_search' => 1]]
        ],
    ]
],

问题原因 #

Elasticsearch的query节点下只能有一个顶级查询类型，不能同时并列function_score和bool两个字段。你现在把两个查询类型平级放在query里，导致解析器无法识别，抛出语法错误。

正确的做法是把原来的bool查询作为function_score的query参数，让function_score基于这个bool查询的结果来应用权重函数。

修复后的代码 #

'query' => [
    'function_score' => [
        // 把原有的bool查询放到function_score的query字段里
        'query' => [
            'bool' => [
                'filter' => [
                    ['range' => [
                        'starttime' => ['lte' => $now],
                    ]]
                ],
                'must' => [
                    ["multi_match" => [
                        'fuzziness' =>  'auto',
                        'query' => $_REQUEST['kw'],
                        'fields' => [
                            'content^2',
                            'teaser^2',
                            'bodytext^2',
                            'title^5',
                            'header^3'
                        ],
                    ]],
                    ['bool' => [
                        'should' => [
                            ['match' => ['sys_language_uid' =>  $sysLanguageUid]],
                            ['match' => ['sys_language_uid' => -1]],
                        ],
                        'minimum_should_match' => 1,
                    ]],
                ],
                'must_not' => [
                    ['match' => ['hidden' => 1]],
                    ['match' => ['deleted' => 1]],
                    ['match' => ['no_search' => 1]]
                ],
            ]
        ],
        'functions' => [
            [
                'filter'=> [
                    'range' => [
                        'tstamp' => [
                            'gte' => 'now-1y',
                            'lte'  => 'now'
                        ]
                    ]
                ],
                'weight' => 5
            ],
            [
                'filter' => [
                    'range' => [
                        'tstamp' => [
                            'gte' => 'now-3yr',
                            'lte' => 'now-1yr'
                        ]
                    ]
                ],
                'weight' => 2
            ]
        ],
        'boost_mode' => 'multiply'
    ]
],

说明 #

修复后，function_score会先执行内部的bool查询获取匹配结果，再对这些结果应用你定义的权重函数，根据tstamp的时间范围提升对应文档的权重，同时保持原有的查询逻辑不变。

内容的提问来源于stack exchange，提问作者user20291865