执行异步查询 Azure 表存储的最佳方式

Question

我有一个使用 Windows Azure Storage Client 3.0 工作的基本 Azure 表存储查询。将其转换为异步查询的最简单方法是什么？是否可以使用异步等待模式？

//Setup the storage account connection
var cloudStorageAccount = CloudStorageAccount.Parse(connectionString);
var cloudTableClient = cloudStorageAccount.CreateCloudTableClient();
var table = cloudTableClient.GetTableReference("SampleTable");

//Get the context
var context = cloudTableClient.GetTableServiceContext();

//Setup the query
var q = from s in table.CreateQuery<SampleEntity>()
        where s.PartitionKey == sampleUID.ToString()
        select s;

//Get the list
var list = q.ToList();

插入和更新实体有 XyzAsync() 方法...我一定遗漏了一些东西。感谢您的帮助。

Answer 1

最新版本的 SDK 现在支持异步 (nuget)。

您可以使用ExecuteSegmentedAsync 方法执行查询：

var query = (from s in table.CreateQuery<SampleEntity>()
            where s.PartitionKey == sampleUID.ToString() select s)
            .AsTableQuery<SampleEntity>();

TableContinuationToken continuationToken = null;
do
{
    // Execute the query async until there is no more result
    var queryResult = await query.ExecuteSegmentedAsync(continuationToken);
    foreach (var entity in queryResult)
    {

    }

    continuationToken = queryResult.ContinuationToken;
} while (continuationToken != null);

我已经转换了本教程的一些示例 (How to use Table storage from .NET)：

1. 创建表格

   async Task CreateATable()
   {
       // Retrieve the storage account from the connection string.
       CloudStorageAccount storageAccount = CloudStorageAccount.Parse(
           CloudConfigurationManager.GetSetting("StorageConnectionString"));
   
       // Create the table client.
       CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
   
       // Create the table if it doesn't exist.
       CloudTable table = tableClient.GetTableReference("people");
       await table.CreateIfNotExistsAsync();
   }
   

2. 将实体添加到表中

   public class CustomerEntity : TableEntity
   {
       public CustomerEntity(string lastName, string firstName)
       {
           this.PartitionKey = lastName;
           this.RowKey = firstName;
       }
   
       public CustomerEntity() { }
   
       public string Email { get; set; }
   
       public string PhoneNumber { get; set; }
   }
   ...
   //The script:
   // Retrieve the storage account from the connection string.
   CloudStorageAccount storageAccount = CloudStorageAccount.Parse(
       CloudConfigurationManager.GetSetting("StorageConnectionString"));
   
   // Create the table client.
   CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
   
   // Create the CloudTable object that represents the "people" table.
   CloudTable table = tableClient.GetTableReference("people");
   
   // Create a new customer entity.
   CustomerEntity customer1 = new CustomerEntity("Harp", "Walter");
   customer1.Email = "Walter@contoso.com";
   customer1.PhoneNumber = "425-555-0101";
   
   // Create the TableOperation object that inserts the customer entity.
   TableOperation insertOperation = TableOperation.Insert(customer1);
   
   // Execute the insert operation.
   await table.ExecuteAsync(insertOperation);
   

3. 插入一批实体

   // Retrieve the storage account from the connection string.
   CloudStorageAccount storageAccount = CloudStorageAccount.Parse(
       CloudConfigurationManager.GetSetting("StorageConnectionString"));
   
   // Create the table client.
   CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
   
   // Create the CloudTable object that represents the "people" table.
   CloudTable table = tableClient.GetTableReference("people");
   
   // Create the batch operation.
   TableBatchOperation batchOperation = new TableBatchOperation();
   
   // Create a customer entity and add it to the table.
   CustomerEntity customer1 = new CustomerEntity("Smith", "Jeff");
   customer1.Email = "Jeff@contoso.com";
   customer1.PhoneNumber = "425-555-0104";
   
   // Create another customer entity and add it to the table.
   CustomerEntity customer2 = new CustomerEntity("Smith", "Ben");
   customer2.Email = "Ben@contoso.com";
   customer2.PhoneNumber = "425-555-0102";
   
   // Add both customer entities to the batch insert operation.
   batchOperation.Insert(customer1);
   batchOperation.Insert(customer2);
   
   // Execute the batch operation.
   await table.ExecuteBatchAsync(batchOperation);
   

4. 等等……

Answer 2

请查看以下来自 Azure 存储团队的博客文章 Tables Deep Dive。新的表服务层包括异步操作，例如 ExecuteQueryAsync（与同步 ExecuteQuery 方法相对应），它与异步等待模式一起使用。另请阅读Storage Library 2.1 Release 帖子，了解有关使用新表服务器层支持 IQueryable 的更多信息。

杰森