Elasticsearch PIT 与 search_after 深分页稳定查询实践

打开 PIT： ``` POST /products/_pit?keep_alive=1m ``` 首次查询（不含 search_after）： ``` POST /_search { "pit": { "id": "", "keep_alive": "1m" }, "size": 50, "sort": [ { "price": "asc" }, { "_shard_doc": "asc" } ], "query": { "term": { "category": "electronics" } } } ``` 后续查询（携带上一页最后一条的 sort 值）： ``` POST /_search { "pit": { "id": "", "keep_alive": "1m" }, "size": 50, "sort": [ { "price": "asc" }, { "_shard_doc": "asc" } ], "search_after": [ 123.45, "g1AAAAB..." ], "query": { "term": { "category": "electronics" } } } ``` 关闭 PIT： ``` DELETE /_pit { "pit_id": "" } ```