WMI - select from Win32_Product takes a long time

Question

I am enumerating installed applications using WMI, and this block is taking a relatively long time to complete no matter how I structure it. It takes 13 seconds in my environment every time. Is there a better (faster) way to check if a program is installed? (I'm using iTunes as an example program to check for)

    private static string Timestamp
    {
        get { return DateTime.Now.ToString("HH:mm:ss.ffff"); }
    }

    private static void LoadInstalledPrograms()
    {
        List<string> installedPrograms = new List<string>();
        Console.WriteLine("0 - {0}", Timestamp);
        ManagementObjectSearcher mos = new ManagementObjectSearcher("SELECT * FROM Win32_Product");
        Console.WriteLine("1 - {0}", Timestamp);
        ManagementObjectCollection managementObjectCollection = mos.Get();
        Console.WriteLine("2 - {0}", Timestamp);
        foreach (ManagementObject mo in managementObjectCollection)
        {
            installedPrograms.Add(mo["Name"].ToString());
        }
        Console.WriteLine("3 - {0}", Timestamp);
        Console.WriteLine("Length - {0}", installedPrograms.Count);
    }

SELECT * FROM Win32_Product

0 - 08:08:51.3762
1 - 08:08:51.3942
2 - 08:08:51.4012
3 - 08:09:04.8326
Length - 300

SELECT * FROM Win32_Product WHERE name = 'iTunes'

0 - 08:14:17.6529
1 - 08:14:17.6709
2 - 08:14:17.6779
3 - 08:14:31.0332
Length - 1

SELECT * FROM Win32_Product WHERE name LIKE 'iTunes'

0 - 08:16:38.2719
1 - 08:16:38.2899
2 - 08:16:38.2999
3 - 08:16:51.5113
Length - 1

SELECT name FROM Win32_Product WHERE name LIKE 'iTunes'

0 - 08:19:53.9144
1 - 08:19:53.9324
2 - 08:19:53.9394
3 - 08:20:07.2794
Length - 1

Answer 1

If you query "Win32_product" the msi-installer checks and validates every product.

The KB article http://support.microsoft.com/kb/974524 shows:

Win32_product Class is not query optimized. Queries such as “select * from Win32_Product where (name like 'Sniffer%')” require WMI to use the MSI provider to enumerate all of the installed products and then parse the full list sequentially to handle the “where” clause. This process also initiates a consistency check of packages installed, verifying and repairing the install. With an account with only user privileges, as the user account may not have access to quite a few locations, may cause delay in application launch and an event 11708 stating an installation failure.

Win32reg_AddRemovePrograms is a much lighter and effective way to do this, which avoids the calls to do a resiliency check, especially in a locked down environment. So when using Win32reg_AddRemovePrograms we will not be calling on msiprov.dll and will not be initiating a resiliency check.

So be careful with "Win32_product".

Update: nice article https://sdmsoftware.com/group-policy-blog/wmi/why-win32_product-is-bad-news/