c# - 查询azure表服务给出不同的结果

Question

我正在尝试使用 Microsoft Azure 存储 SDK 查询 azure 表存储。发送简单请求会返回预期结果(类似于 https://learn.microsoft.com/en-us/azure/storage/storage-dotnet-how-to-use-tables#retrieve-a-range-of-entities-in-a-partition )。但是当我发送像这样的更复杂的查询时:

  (((((((((PartitionKey eq 'LOS-test1-20161218') or (PartitionKey eq 'SPA-test1-20161218')) or (PartitionKey eq 'LOS-test2-20161219')) or (PartitionKey eq 'SPA-test2-20161219')) or (PartitionKey eq 'SPA-test3-20161218')) or (PartitionKey eq 'LOS-test3-20161218')) or (PartitionKey eq 'SPA-test4-20161219')) or (PartitionKey eq 'LOS-test4-20161219')) or (PartitionKey eq 'SPA-test5-20161219')) or (PartitionKey eq 'LOS-test5-20161219')

我只得到了部分预期结果(三分之一)。同时，当我使用 Microsoft Azure Storage Explorer 运行此查询时，我得到了正确的数据。

为什么会发生这种情况？

private string GenerateFilterCondition(string s, string c, DateTime date)
{
        return TableQuery.GenerateFilterCondition(
            "PartitionKey", QueryComparisons.Equal,
            s + "-" + c + "-" + date.ToString("yyyyMMdd"));
}

private List<SiteSpecificDataTableDataSet> GetSiteSpecificDataTableDataSet()
{           
    _connection.Open();
    DateTime selectedDate = DateTime.Now.AddDays(-1);

    TableQuery<DataEntity> tq = new TableQuery<DataEntity>().Where(GenerateFilterCondition("SPA", "test5", selectedDate));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("LOS", "test5", selectedDate));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("SPA", "test4", selectedDate.AddDays(1)));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("LOS", "test4", selectedDate.AddDays(1)));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("LOS", "test3", selectedDate));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("SPA", "test3", selectedDate));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("LOS", "test2", selectedDate.AddDays(1)));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("SPA", "test2", selectedDate.AddDays(1)));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("LOS", "test1", selectedDate.AddDays(1)));
    tq = AddFilterORToTableQuery(tq.FilterString, GenerateFilterCondition("SPA", "test1", selectedDate.AddDays(1)));

    IEnumerable<DataEntity> entities = _connection.QueryData(tq);
}

并且 QueryData 看起来像:

    IEnumerable<DataEntity> res;
            List<DataEntity> queryResult = new List<DataEntity>();
            CloudTableClient tableClient = _storageAccount.CreateCloudTableClient();
            CloudTable table = tableClient.GetTableReference("data");
            TableContinuationToken tct = null;
            do
            {
                // Retrieve a segment (up to 1,000 entities).
                TableQuerySegment<DataEntity> tableQueryResult = table.ExecuteQuerySegmentedAsync(query, tct).Result;                
                if (tableQueryResult.Results.Count == 0) break;
                tct = tableQueryResult.ContinuationToken;
                foreach (var result in tableQueryResult.Results)
                {
                    queryResult.Add(result);
                }

            } while (tct != null);
            res = queryResult;

Answer 1

代码中的这个条件不正确:“if (tableQueryResult.Results.Count == 0) break”，即使结果为空，您可能仍然需要继续查询。

正确的条件应该是:“if (tableQueryResult.ContinuationToken == null) break”。

顺便说一句，强烈不建议在一个过滤字符串中查询不同的分区键，因为根据 Azure 表设计，它会导致整个表扫描，这在性能上很糟糕。您需要将查询拆分为多个(一次一个分区键)查询以获得更好的性能。