Question

I am using windows azure table storage. My problem is that the access of entities for a given user from table is taking long time. The code which i am using to access the table is as follows :

   public CloudTableQuery<T> GetEntites(string username)  
   {
        try
        {
            CloudTableQuery<T> entries =
                (from e in ServiceContext.CreateQuery<T>(TableName)
                 where e.PartitionKey == username
                 select e).AsTableServiceQuery();

            return entries;
        }
        catch (Exception)
        { return null; }
    }

The total entities in the table are currently only 100 or so. For example : The query seems to take as long as 40 seconds to return 25 entities for a given user. Please suggest if there is any scope for improvement in the code for faster performance ?

Answer 1

The real problem here is you are returning queries instead of entities, and you are likely executing a query again for each returned entity (query). Define your entity with something like:

public class UserEntity
{
    public string UserName { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
}

Then define your table storage entity with something like:

public class StoredUserEntity : TableServiceEntity
{
    public StoredUserEntity (string username)
    {
        this.PartitionKey = username;
        this.RowKey = Guid.NewGuid().ToString();
        this.Timestamp = DateTime.Now;
    }

    public string Email { get; set; }
    public string Name { get; set; }
}

Then your query should actually return a list of UserEntities:

    public List<UserEntity> GetUserData(string username)
    {
        var q = _tableContext.CreateQuery<StoredUserEntity>(_tableName);
        return
            q.ToList().Select(x => new UserEntity {UserName = x.PartitionKey, Email = x.Email, Name = x.Name}).Where(x => x.UserName == username).ToList();
    }