How to modify Server side paging size - pagination

Question

I have an OData Web API service using .NET 4.5. It has a WebApi controller derived from EntitySetController:
public class WorkItemsController : EntitySetController<WorkItem, string>
{
[Queryable(PageSize=100)]
public override IQueryable<WorkItem> Get()
{## Heading ##
// go to AWS DynamoDb, get the workitems and then return
}
}
As you can see, I set the server-side page size to 100 by default. Later I realize that I need to increase the size programmatically inside the Get() function. Does anyone know how to do it?
If you want to know the reason, here is why:
AWS DynamoDb doesn't support $skip or $top query. Each time a client wants to get a collection of workitems, I need to get all workitems from DynamoDb. When the number is big, it takes very long time if each time we only return 100 items back to user. So my strategy is to double/triple the number of workitems we return to user each time. So user will get 100, 200, 400, 800 workitems with consecutive requests. Assuming there are 1500 workitems in DynamoDb, I will query only 4 times to return all of them back to user. If we keep a constant pagesize, like 100, I need to query 15 times.

Answer 1

You can invoke the ODataQueryOptions in your method and set the page size.
public IQueryable Get(ODataQueryOptions queryOptions)
{
var settings = new ODataQuerySettings { PageSize = 100 };
var result = GetResult();
return queryOptions.ApplyTo(result, settings);
}

Answer 2

This is exactly the issue, that LINQ2DynamoDB addresses. To support $skip and $top (that is, Enumerable.Skip() and Enumerable.Take()), it caches the results returned by DynamoDb in ElastiCache. So that server-side paging works much more efficiently and the number of read operations is greatly reduced.
Moreover, LINQ2DynamoDB supports OData automatically, so maybe you don't even need to do any WebApi controllers.
Why not trying it? :)