R – Order SharePoint search results by more columns

Concatenating the querysets into a list is the simplest approach. If the database will be hit for all querysets anyway (e.g. because the result needs to be sorted), this won't add further cost.

from itertools import chain
result_list = list(chain(page_list, article_list, post_list))

Using itertools.chain is faster than looping each list and appending elements one by one, since itertools is implemented in C. It also consumes less memory than converting each queryset into a list before concatenating.

Now it's possible to sort the resulting list e.g. by date (as requested in hasen j's comment to another answer). The sorted() function conveniently accepts a generator and returns a list:

result_list = sorted(
    chain(page_list, article_list, post_list),
    key=lambda instance: instance.date_created)

If you're using Python 2.4 or later, you can use attrgetter instead of a lambda. I remember reading about it being faster, but I didn't see a noticeable speed difference for a million item list.

from operator import attrgetter
result_list = sorted(
    chain(page_list, article_list, post_list),
    key=attrgetter('date_created'))

You need real Windows impersonation to do this. The SPSite impersonation is not real impersonation - it just tells the WSS object model to write another user id to the created and modified fields in the content database.

For Windows impersonation you will unfortunately need both the login and password unless you want to impersonate the application pool account using SPSecurity.RunWithElevatedPrivileges

You can implement Windows impersonation as follows:

using (Impersonator imp = new Impersonator("user", "domain", "password"))
{
  // Do stuff impersonated
}

where the Impersonator class is implemented as:

public sealed class Impersonator : IDisposable
{
  private WindowsImpersonationContext impersonationContext;

  public Impersonator(string user, string domain, string password)
  {
    WindowsIdentity id = Logon(user, domain, password);
    impersonationContext = id.Impersonate();
  }

  public void Dispose()
  {
    if (impersonationContext != null)
    {
      impersonationContext.Undo();
      impersonationContext = null;
    }
  }

  private WindowsIdentity Logon(string user, string domain, string password)
  {
    WindowsIdentity identity;
    IntPtr handle = IntPtr.Zero;
    bool logonSucceeded = LogonUser(
      user, domain, password,
      8,   // LOGON32_LOGON_NETWORK_CLEARTEXT
      0,   // LOGON32_PROVIDER_DEFAULT
      ref handle);

    if (!logonSucceeded)
    {
      int errorCode = Marshal.GetLastWin32Error();
      throw new UnauthorizedAccessException("User logon failed. Error Number: " + errorCode);
    }

    identity = new WindowsIdentity(handle);
    CloseHandle(handle);

    return identity;
  }

  [DllImport("advapi32.dll", SetLastError = true)]
  private static extern bool LogonUser(string lpszUsername,
    string lpszDomain,
    string lpszPassword,
    int dwLogonType,
    int dwLogonProvider,
    ref IntPtr phToken);

  [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
  private static extern bool CloseHandle(IntPtr handle);
}