next_doc耗时较长怎么优化？

查询语句：
{
    "query": {
        "match": {
            "tessContext": "addition variables data: 28 69 43 32 42 72 66 49 70 60 250 550 575 11 15 31 34 10 6 2 where: amount"
        }
    },
    "_source": ["questionId", "spiderStatus", "tessContext", "deleteStatus"],
    "size": 100
}
索引映射：
"mappings": {"_doc": {

"properties": {

"lengLabel": {

"type": "long"

},
"spiderStatus": {

"type": "long"

},
"tessContext": {

"fielddata": true,
"type": "text",
"fields": {

"keyword": {

"ignore_above": 256,
"type": "keyword"

}

}

},
"questionId": {

"type": "long"

},
"deleteStatus": {

"type": "long"

},
"_class": {

"type": "text",
"fields": {

"keyword": {

"ignore_above": 256,
"type": "keyword"

}

}

},
"courseId": {

"type": "long"

},
"subjectId": {

"type": "long"

}

}

}}
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