Elasticsearch Scroll paging retrieval case sharing

Elasticsearch Scroll paging retrieval case sharing

1. Preparation
reference document " Introduction to the use of high-performance elasticsearch ORM development library " Import and configure es client bboss

2. Define scroll retrieval dsl
First define a simple scroll dsl retrieval script

<properties>
    <property name="scrollQuery">
        <![CDATA[
         {           
           ## Here are all operations with constants, and variables can be parameterized in actual scenarios
            "size":1000,
            "query": {
                "term" : {
                    "gc.jvmGcOldCount" : 3 ##Parameter values ​​can be defined as variables and passed in through parameters
                }
            }
        }
        ]]>
    </property>
</properties>

3.Scroll retrieval code

@Test
	public void testScroll(){
		ClientInterface clientUtil = ElasticSearchHelper.getConfigRestClientUtil("esmapper/scroll.xml");
		//scroll paging retrieval, map the retrieval result to a Map object, or map it to a custom entity object
		ESDatas<Map> response = clientUtil.searchList("agentstat-*/_search?scroll=1m",
                              "scrollQuery",//For the dsl script name, configure in the esmapper/scroll.xml file
                               Map.class);
		List<Map> datas = response.getDatas();//The first page data
		List<String > scrollIds = new ArrayList<>();//It is used to record the scrollid of each scroll, which is convenient for clearing after retrieval
		long totalSize = response.getTotalSize();//Number of total records
		String scrollId = response.getScrollId();
		if(scrollId != null)
			scrollIds.add(scrollId);
		System.out.println("totalSize:"+totalSize);
		System.out.println("scrollId:"+scrollId);
		if(datas != null && datas.size() > 0) {//1000 records per page, traverse scroll paging results by iterating scrollid
			do {

				response = clientUtil.searchScroll("1m",scrollId,Map.class);
				scrollId = response.getScrollId();//scrollid of each page
				if(scrollId != null)
					scrollIds.add(scrollId);
				datas = response.getDatas();//Number of records per page
				if(datas == null || datas.size() == 0){
					break;
				}
			} while (true);
		}
		//Query and print the scroll context information that exists on the es server
		String scrolls = clientUtil.executeHttp("_nodes/stats/indices/search", ClientUtil.HTTP_GET);
		System.out.println(scrolls);
		//Clear the scroll context information, although the scrollid will automatically expire after more than 1 minute, it is a good habit to manually delete the unused scrollid and release es resources
		if(scrollIds.size() > 0) {
			scrolls = clientUtil.deleteScrolls(scrollIds);
			System.out.println(scrolls);
		}
		//View the scroll context information after cleaning
		scrolls = clientUtil.executeHttp("_nodes/stats/indices/search", ClientUtil.HTTP_GET);
		System.out.println(scrolls);
	}

4. Scroll case project address and code file
project address:

https://gitee.com/bboss/elasticsearchdemo/

scroll to retrieve the corresponding code and script files:

https://gitee.com/bboss/elasticsearchdemo/blob/master/src /test/resources/esmapper/scroll.xml

https://gitee.com/bboss/elasticsearchdemo/blob/master/src/test/java/org/frameworkset/elasticsearch/TestScrollQuery.java