Question

我正在尝试使用Microsoft Azure Storage SDK查询azure表存储。发送简单请求会返回预期结果（类似于https://docs.microsoft.com/en-us/azure/storage/storage-dotnet-how-to-use-tables#retrieve-a-range-of-entities-in-a-partition）。但是当我发送一个更复杂的查询时，就像这样：

  (((((((((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')

我只得到预期结果的一部分（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。

为什么会这样？

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);
}

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

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

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

BTW，强烈建议不要在一个过滤字符串中查询不同的分区键，因为根据Azure Table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。

查询azure表服务会产生不同的结果

1 个答案: