Skip to main content

How we can remove millions of entities from a Windows Azure Table (part 2)

In one of my latest post I tacked about how we can remove a lot of entities from Windows Azure – deleting the table.
This solution works but we will have to face up with an odd problem. When we are deleting a table, we only mark it for deletion, our client will not be able to access the table and in background Windows Azure will start deleting the table. If we have a table with millions of entities will face up with a big problem. Until Windows Azure will finish deletion of the table will not be able to create a new table with the same time.
This can be a blocker. We don’t want to wait 4 hours, until our table is deleted to be able to recreate another one.
And here is a big BUT. We can be smart and use ListTables. Basically we can create another table that have the name something like [MyTableName]+[Guid] and using ListTable method to retrieve the name of our table only using [MyTableName].
Using this solution, we can add mark our old table for delegation and create a new table with a similar name where we can store our entities. In this way we will be able to remove items from a table in only a few seconds.  Even if this “virtual” clean it works great and can speed up our applications.
The following code can be used to delete a table:
CloudTableClient tableStorage = new CloudTableClient([tableUri],[credential]);
string tableName = [MyTableName];
tableName = tableStorage.ListTables(tableName).FirstOrDefault();
if (tableName != null)
{
  tableStorage.DeleteTableIfExist(tableName);
}
The following code can be used to retrieve the name of our table and recreate a new table of don’t exist:
string tableName = tableStorage.ListTables([MyTableName]).FirstOrDefault();
if (tableName == null)
{
  tableName = [MyTableName] + Guid.NewGuid();
  tableStorage.CreateTableIfNotExist(tableName);
}

The only downside of this solution is that there are some seconds when we will not have a table where clients can access it. If we can leave with this solution and we can manage this problem on the client side than we can use it without any kind of problem.

Comments

  1. The question is: why/when would you need to do something like this is a real application? :)
    (sure, for testing/debugging scenarios it might be useful, but other than that..)

    ReplyDelete
    Replies
    1. There are times when you need to clean a table very fast. For example a table that store the assignment between updates and system where this update is available.

      Delete

Post a Comment

Popular posts from this blog

Windows Docker Containers can make WIN32 API calls, use COM and ASP.NET WebForms

After the last post , I received two interesting questions related to Docker and Windows. People were interested if we do Win32 API calls from a Docker container and if there is support for COM. WIN32 Support To test calls to WIN32 API, let’s try to populate SYSTEM_INFO class. [StructLayout(LayoutKind.Sequential)] public struct SYSTEM_INFO { public uint dwOemId; public uint dwPageSize; public uint lpMinimumApplicationAddress; public uint lpMaximumApplicationAddress; public uint dwActiveProcessorMask; public uint dwNumberOfProcessors; public uint dwProcessorType; public uint dwAllocationGranularity; public uint dwProcessorLevel; public uint dwProcessorRevision; } ... [DllImport("kernel32")] static extern void GetSystemInfo(ref SYSTEM_INFO pSI); ... SYSTEM_INFO pSI = new SYSTEM_INFO(...

How to audit an Azure Cosmos DB

In this post, we will talk about how we can audit an Azure Cosmos DB database. Before jumping into the problem let us define the business requirement: As an Administrator I want to be able to audit all changes that were done to specific collection inside my Azure Cosmos DB. The requirement is simple, but can be a little tricky to implement fully. First of all when you are using Azure Cosmos DB or any other storage solution there are 99% odds that you’ll have more than one system that writes data to it. This means that you have or not have control on the systems that are doing any create/update/delete operations. Solution 1: Diagnostic Logs Cosmos DB allows us activate diagnostics logs and stream the output a storage account for achieving to other systems like Event Hub or Log Analytics. This would allow us to have information related to who, when, what, response code and how the access operation to our Cosmos DB was done. Beside this there is a field that specifies what was th...

Cloud Myths: Cloud is Cheaper (Pill 1 of 5 / Cloud Pills)

Cloud Myths: Cloud is Cheaper (Pill 1 of 5 / Cloud Pills) The idea that moving to the cloud reduces the costs is a common misconception. The cloud infrastructure provides flexibility, scalability, and better CAPEX, but it does not guarantee lower costs without proper optimisation and management of the cloud services and infrastructure. Idle and unused resources, overprovisioning, oversize databases, and unnecessary data transfer can increase running costs. The regional pricing mode, multi-cloud complexity, and cost variety add extra complexity to the cost function. Cloud adoption without a cost governance strategy can result in unexpected expenses. Improper usage, combined with a pay-as-you-go model, can result in a nightmare for business stakeholders who cannot track and manage the monthly costs. Cloud-native services such as AI services, managed databases, and analytics platforms are powerful, provide out-of-the-shelve capabilities, and increase business agility and innovation. H...