Elasticsearch Java API 的使用(8)—Scroll (遊標)API詳解
阿新 • • 發佈:2019-02-10
滾動查詢
Elasticsearch中進行大資料量查詢時,往往因為裝置、網路傳輸問題影響查詢資料的效率;Elasticsearch中提供了Scroll(遊標)的方式對資料進行少量多批次的滾動查詢,來提高查詢效率。
public class Scroll {
public static void main(String[] args) {
try{
long startTime = System.currentTimeMillis();
/*建立客戶端*/
//client startup
//設定叢集名稱
Settings settings = Settings.builder()
.put("cluster.name", "elsearch")
.put("client.transport.sniff", true)
.build();
//建立client
TransportClient client = new PreBuiltTransportClient(settings)
.addTransportAddress(new InetSocketTransportAddress(
InetAddress.getByName("54.223.232.95"),9300));
List<String> result = new ArrayList<>();
String scrollId = "";
//第一次請求
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
//TODO: 設定查詢條件
RangeQueryBuilder rangequerybuilder = QueryBuilders
.rangeQuery("inputtime")
.from("2016-12-14 02:00:00").to("2016-12-14 07:59:59");
sourceBuilder.query(QueryBuilders.boolQuery()
.must(QueryBuilders
.matchPhraseQuery("pointid","W3.UNIT1.10HFC01CT013"))
.must(rangequerybuilder))
.size(100)//如果開啟遊標,則滾動獲取
.sort("inputtime", SortOrder.ASC);
//查詢
SearchRequest request = Requests.searchRequest("pointdata");
request.scroll("2m");
request.source(sourceBuilder);
SearchResponse response = client.search(request).actionGet();
//TODO:處理資料
SearchHits hits = response.getHits();
for(int i = 0; i < hits.getHits().length; i++) {
//System.out.println(hits.getHits()[i].getSourceAsString());
result.add(hits.getHits()[i].getSourceAsString());
}
//記錄滾動ID
scrollId = response.getScrollId();
while(true){
//後續的請求
//scrollId = query.getScollId();
SearchScrollRequestBuilder searchScrollRequestBuilder = client
.prepareSearchScroll(scrollId);
// 重新設定滾動時間
//TimeValue timeValue = new TimeValue(30000);
searchScrollRequestBuilder.setScroll("2m");
// 請求
SearchResponse response1 = searchScrollRequestBuilder.get();
//TODO:處理資料
SearchHits hits2 = response1.getHits();
if(hits2.getHits().length == 0){
break;
}
for(int i = 0; i < hits2.getHits().length; i++) {
result.add(hits2.getHits()[i].getSourceAsString());
}
//下一批處理
scrollId = response1.getScrollId();
}
System.out.println(result.size());
long endTime = System.currentTimeMillis();
System.out.println("Java程式執行時間:" + (endTime - startTime) + "ms");
}catch(Exception e){
e.printStackTrace();
}
}