ElasticSearch Scroll滾動查詢（查詢資料超過10000）

ElasticSearch官方預設查詢資料是10000條，查詢第10001時會報錯：Result window is too large, from + size must be less than or equal to...

以下是From/Size查詢方法的官方文檔：

https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-request-from-size.html

今天我們重點介紹一下：Scroll滾動查詢

以下是Scroll官方文檔：

https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-request-scroll.html

代碼：

@Autowired

private RestHighLevelClient restHighLevelClient;

public void scrollDemo() {

//構造查詢條件

SearchRequest searchRequest = new SearchRequest("索引庫");

SearchSourceBuilder builder = new SearchSourceBuilder();

//設定查詢逾時時間

Scroll scroll = new Scroll(TimeValue.timeValueMinutes(1L));

builder.query(QueryBuilders.rangeQuery("字段").gte("開始時間").lte("結束時間"));

//設定最多一次能夠取出10000筆資料，從第10001筆資料開始，将開啟滾動查詢 PS:滾動查詢也屬于這一次查詢，隻不過因為一次查不完，分多次查

builder.size(10000);

searchRequest.source(builder);

//将滾動放入

searchRequest.scroll(scroll);

SearchResponse searchResponse = null;

try {

searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

} catch (IOException e) {

log.error("查詢索引庫失敗", e.getMessage(), e);

}

SearchHits hits = searchResponse.getHits();

//記錄要滾動的ID

String scrollId = searchResponse.getScrollId();

//TODO 對結果集的處理

//滾動查詢部分，将從第10001筆資料開始取

SearchHit[] hitsScroll = hits.getHits();

while (hitsScroll != null && hitsScroll.length > 0 ) {

//構造滾動查詢條件

SearchScrollRequest searchScrollRequest = new SearchScrollRequest(scrollId);

searchScrollRequest.scroll(scroll);

try {

//響應必須是上面的響應對象，需要對上一層進行覆寫

searchResponse = restHighLevelClient.scroll(searchScrollRequest, RequestOptions.DEFAULT);

} catch (IOException e) {

log.error("滾動查詢失敗",e.getMessage(),e);

}

scrollId = searchResponse.getScrollId();

hits = searchResponse.getHits();

hitsScroll = hits.getHits();

//TODO 同上面完全一緻的結果集處理

//清除滾動，否則影響下次查詢

ClearScrollRequest clearScrollRequest = new ClearScrollRequest();

clearScrollRequest.addScrollId(scrollId);

ClearScrollResponse clearScrollResponse = null;

clearScrollResponse = restHighLevelClient.clearScroll(clearScrollRequest, RequestOptions.DEFAULT);

log.error("滾動查詢清除失敗",e.getMessage(),e);

//清除滾動是否成功

boolean succeeded = clearScrollResponse.isSucceeded();

}