在后台重新建立索引时，将索引重新混叠放在哪里？

Question

我尝试用Java重新索引ES索引：

// reindex all documents from the old into the new index
QueryBuilder qb = QueryBuilders.matchAllQuery();
SearchResponse scrollResp = client.prepareSearch("my_index").setSearchType(SearchType.SCAN).setScroll(new TimeValue(600000)).setQuery(qb).setSize(100).execute().actionGet();
while (true) {
    scrollResp = client.prepareSearchScroll(scrollResp.getScrollId()).setScroll(new TimeValue(600000)).execute().actionGet();

    final int documentFoundCount = scrollResp.getHits().getHits().length;

    // Break condition: No hits are returned
    if (documentFoundCount == 0) {
        break;
    }

    // otherwise add all documents which are found (in this scroll-search) to a bulk operation for reindexing.
    logger.info("Found {} documents in the scroll search, re-indexing them via bulk now.", documentFoundCount);
    BulkRequestBuilder bulk = client.prepareBulk();
    for (SearchHit hit : scrollResp.getHits()) {
        bulk.add(new IndexRequest(newIndexName, hit.getType()).source(hit.getSource()));
    }

    bulk.execute(new ActionListener<BulkResponse>() {
        @Override public void onResponse(BulkResponse bulkItemResponses) {
            logger.info("Reindexed {} documents from '{}' to '{}'.", bulkItemResponses.getItems().length, currentIndexName, newIndexName);
        }

        @Override public void onFailure(Throwable e) {
            logger.error("Could not complete the index re-aliasing.", e);
        }
    });
}

// these following lines should only be executed if the re-indexing was successful for _all_ documents.
logger.info("Finished re-indexing all documents, now setting the aliases from the old to the new index.");
try {
    client.admin().indices().aliases(new IndicesAliasesRequest().removeAlias(currentIndexName, "my_index").addAlias("my_index", newIndexName)).get();
    // finally, delete the old index
    client.admin().indices().delete(new DeleteIndexRequest(currentIndexName)).actionGet();
} catch (InterruptedException | ExecutionException e) {
    logger.error("Could not complete the index re-aliasing.", e);
}

一般来说，这是可行的，但这种方法有一个问题：

如果在重新索引过程中出现故障，例如，它花费的时间太长，并且被某个事务监视停止(它在EJB启动期间运行)，则会重新设置别名，并且仍然会删除旧的索引。

如果且仅当所有批量请求都成功时，我如何才能重新设置别名？

Answer 1

您不需要等到批量请求完成。如果在不使用actionGet()的情况下调用execute()，则最终只能异步运行。这意味着在完全构建新索引之前，您将开始更改别名和删除索引。

另外：

client.admin().indices().aliases(new IndicesAliasesRequest().removeAlias(currentIndexName, "my_index").addAlias("my_index", newIndexName)).get();

这应该以execute()和.actionGet()结束，而不是get()。这可能就是为什么没有设置别名的原因