ExecuteNextAsync不起作用 [英] ExecuteNextAsync Not Working

问题描述

我正在使用Azure DocumentDB.我正在查看ExecuteNextAsync操作.我看到的是ExecuteNextAsync不返回任何重排.我使用的是我在网上找到的示例，并且不会产生任何结果.如果我对初始查询调用枚举操作，则返回结果.有没有显示使用ExecuteNextAsync的完整配置的示例?

I am working with Azure DocumentDB. I am looking at the ExecuteNextAsync operation. What I am seeing is the the ExecuteNextAsync returns no resluts. I am using examples I have found on line and don't generate any results. If I call an enumeration operation on the initial query results are returned. Is there an example showing the complete configuration for using ExecuteNextAsync?

更新 更明确地说，我实际上没有得到任何结果.该调用似乎只是在运行，并且没有错误生成.

Update To be more explicit I am not actually getting any results. The call seems to just run and no error is generated.

玩弄集合的定义，我发现当我将集合大小设置为250GB时，就会发生这种情况.我测试了10GB的存储集，并且确实工作了一段时间.最新测试表明该操作现在再次挂起.

Playing around with the collection defintion, I found that when I set the collection size to 250GB that this occurred. I tested with the collection to 10GB and it did work, for a while. Latest testing shows that the operation is now hanging again.

我生成了两个集合.第一个集合似乎正常工作.第二个似乎无法执行此操作.

I have two collections generated. The first collection appears to work properly. The second one appears to fail on this operation.

推荐答案

对ExecuteNextAsync的单个调用可能返回0个结果，但是当您通过调用直到HasMoreResults为false来运行查询以完成查询时，您将始终得到完整的结果.

Individual calls to ExecuteNextAsync may return 0 results, but when you run the query to completion by calling it until HasMoreResults is false, you will always get the complete results.

几乎总是一次调用ExecuteNextAsync会返回结果，但是由于以下两个原因，您通常可以得到0个结果:

Almost always, a single call to ExecuteNextAsync will return results, but you may get 0 results commonly due to two reasons:

• 如果查询是扫描，则DocumentDB将根据可用吞吐量进行部分处理.此处不会返回任何结果，但是会返回基于最新进度的新延续令牌以恢复执行.
• 如果是跨分区查询，则每个调用都针对单个分区执行.在这种情况下，如果该分区没有与查询匹配的文档，则该调用将不返回任何结果.

如果希望查询确定性地返回结果，则必须使用SELECT TOP而不是使用延续令牌/ExecuteNextAsync作为分页机制.通过将FeedOptions.MaxDegreeOfParallelism更改为-1，您还可以跨多个分区并行读取查询结果.

If you want queries to deterministically return results, you must use SELECT TOP vs. using the continuation token/ExecuteNextAsync as a mechanism for paging. You can also read query results in parallel across multiple partitions by changing FeedOptions.MaxDegreeOfParallelism to -1.

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