elasticsearch获取大批量数据时 深度分页(from&size) VS scroll游标查询

 1 @Override
 2     public <T> void delete(DeleteQuery deleteQuery, Class<T> clazz) {
 3 
 4         String indexName = !StringUtils.isEmpty(deleteQuery.getIndex()) ? deleteQuery.getIndex()
 5                 : getPersistentEntityFor(clazz).getIndexName();
 6         String typeName = !StringUtils.isEmpty(deleteQuery.getType()) ? deleteQuery.getType()
 7                 : getPersistentEntityFor(clazz).getIndexType();
 8         Integer pageSize = deleteQuery.getPageSize() != null ? deleteQuery.getPageSize() : 1000;
 9         Long scrollTimeInMillis = deleteQuery.getScrollTimeInMillis() != null ? deleteQuery.getScrollTimeInMillis()
10                 : 10000l;
11 
12         SearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(deleteQuery.getQuery()).withIndices(indexName)
13                 .withTypes(typeName).withPageable(PageRequest.of(0, pageSize)).build();
14 
15         SearchResultMapper onlyIdResultMapper = new SearchResultMapper() {
16             @Override
17             public <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> clazz, Pageable pageable) {
18                 List<String> result = new ArrayList<String>();
19                 for (SearchHit searchHit : response.getHits().getHits()) {
20                     String id = searchHit.getId();
21                     result.add(id);
22                 }
23                 if (result.size() > 0) {
24                     return new AggregatedPageImpl<T>((List<T>) result, response.getScrollId());
25                 }
26                 return new AggregatedPageImpl<T>(Collections.EMPTY_LIST, response.getScrollId());
27             }
28         };
29 
30         Page<String> scrolledResult = startScroll(scrollTimeInMillis, searchQuery, String.class, onlyIdResultMapper);
31         BulkRequestBuilder bulkRequestBuilder = client.prepareBulk();
32         List<String> ids = new ArrayList<String>();
33 
34         do {
35             ids.addAll(scrolledResult.getContent());
36             scrolledResult = continueScroll(((ScrolledPage<T>)scrolledResult).getScrollId(), scrollTimeInMillis, String.class, onlyIdResultMapper);
37         } while(scrolledResult.getContent().size() != 0);
38 
39         for (String id : ids) {
40             bulkRequestBuilder.add(client.prepareDelete(indexName, typeName, id));
41         }
42 
43         if (bulkRequestBuilder.numberOfActions() > 0) {
44             bulkRequestBuilder.execute().actionGet();
45         }
46 
47         clearScroll(((ScrolledPage<T>) scrolledResult).getScrollId());
48     }