Querying on Azure table storage doesnt work beyond a certain number of entities?

问题

Consider my scenario. I have about 200 partitions and each partition has about 1000 rowkeys(entities) or even more. So when i am making any query fetching records of a partition which is albhabetically last(starting with "z"), it doesnt return any results.

Below is a sample query -

audioRecordServiceContext.QueryableEntities
                         .Where(p => p.PartitionKey == channel && 
                                     p.IsDedication == true && 
                                     p.IsBroadcast == true && 
                                     p.BroadcastTime >= time && 
                                     p.BroadcastTime < time.AddHours(1))
                         .ToList();

When i pass a channel starting with initial alphabets it returns entities properly but when I give a channel starting with probabaly "Z", it doesnt return any entities.

Any idea how i can tackle this issue?

EDIT:

Query string

http://sampleservice/devstoreaccount1/AudioRecord()?$filter=Username eq 'username'

Fiddler response for the query

**HTTP/1.1 200 OK
Cache-Control: no-cache
Transfer-Encoding: chunked
Content-Type: application/atom+xml;charset=utf-8
Server: Windows-Azure-Table/1.0 Microsoft-HTTPAPI/2.0
x-ms-request-id: 06dff157-f693-49a6-ade7-b7165a4d3dfb
x-ms-version: 2009-09-19
x-ms-continuation-NextPartitionKey: 1!16!QWZnaGFuaXN0YW4-
x-ms-continuation-NextRowKey: 1!48!YTZiOGQxZmYtYjNkYy00NDEyLTk2YmItZTViNmUyMWNhYzJi
Date: Wed, 04 Sep 2013 12:19:03 GMT**

回答1:

Here is a sample code that fetches as many entities as needed based on the query being passed; in my environment this returns over 10,000 entities and it handles the continuation tokens automatically. I am not 100% sure of the SDK version this is using, but it should work with 1.7. The magic here is performed by the AsTableServiceQuery, which is an extension method provided by the SDK that performs both the pagination, and automatic retries.

The _tableName variable contains the name of my table.

CloudStorageAccount storageAccount = CloudStorageAccount.Parse(ConnectionString);
            CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
            TableServiceContext serviceContext = tableClient.GetDataServiceContext();

            var partitionQuery =
                (from e in serviceContext.CreateQuery<MyData1>(_tableName)
                 where e.PartitionKey.CompareTo("15") >= 0 && e.PartitionKey.CompareTo("39") <= 0
                 select new MyData1()
                 {
                     PartitionKey = e.PartitionKey,
                     RowKey = e.RowKey,
                     Timestamp = e.Timestamp,
                     Message = e.Message,
                     Level = e.Level,
                     Severity = e.Severity
                 }
                 ).AsTableServiceQuery();

            return partitionQuery.ToList<MyData1>();

The above code depends on a class called MyData1, defined as such:

public class MyData1 : TableServiceEntity
{
    public string Message { get; set; }
    public string Level { get; set; }
    public string Severity { get; set; }
}

Hope this helps...

来源：https://stackoverflow.com/questions/18467181/querying-on-azure-table-storage-doesnt-work-beyond-a-certain-number-of-entities

标签

linq

azure

azure-storage

azure-table-storage