{
  "error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [publishDate] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."
      }
    ],
    "type": "search_phase_execution_exception",
    "reason": "all shards failed",
    "phase": "query",
    "grouped": true,
    "failed_shards": [
      {
        "shard": 0,
        "index": "bbs",
        "node": "3t-pKsnfSOidEJQ3nZihmQ",
        "reason": {
          "type": "illegal_argument_exception",
          "reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [publishDate] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."
        }
      }
    ]
  },
  "status": 400
}

创建索引后，搜索，加上发布时间（publishDate）排序时报错，不加（相关度排序）时，返回正常。

一开始是怀疑，发布时间为空导致的，就在创建索引时，加了判断，为null时强制复制 new Date()，还是不行。

最终看了下mapping，发现同事在创建索引时，发布时间字段，未设置为Date，而是text。text是默认分词的，不能用于聚合和排序。最终删除了索引，重建mapping，将publishDate设置为Date类型，问题解决