Performance reading large array >40K entries

PowerShell Help
1

Hi

I’m trying to find the fastest way to search a large array (40K entries) for a value. However, I’m struggling with the way in which the array is working.

I read in all AD users as shown below

$AllADUsers = Get-ADUser -Filter "*" -properties SAMAccountName, DisplayName, UserPrincipalName, Company, Office,Department, Manager, Description, Created, LastLogonDate, EmployeeType,Info
-Server $ADServer -Credential $c
|select SAMAccountName, DisplayName, UserPrincipalName, Company, Office, Department, Manager,
Description, Created, LastLogonDate, EmployeeType,Info
Now this is why I have a query

If I search the array using the .Contains method it finds the entry in around 2ms

$AllADUsers.Contains($SearchID)
But if I then try to pull the data for the record using the where method it takes 1 second
$AllADUsers.Where({$_.UserPrincipalName -eq "$SearchID"})
So why can it find the value in 2ms using contains but then take more than 1 second to read the actual record. Its as if it is using a different search algorithm in the where which takes longer.

In fact it was faster to use Get-AdUser for each search using on 900ms than to pull it from the array.

I’ve also tried other variations to no avail, such as:

$AllADUsers | where-object {$_.UserPrincipalName -eq $SearchID}
 

Any help gratefully received.

 

Thanks

Keith

2

Why are you pulling all entries just to get individual results? You are loading 40k objects into memory to search for a single item. Why not just get what you need?

Get-ADUser -Filter {UserPrincipalName -eq $SearchID}

Active Directory most likely is indexing common unique search items for more efficient searching. When you pull this into memory and search this way, you are doing a plain search with no efficiency and are at the mercy of these filters.

3

hi

I’m doing an Azure audit on AAD and pulling out additional information to supplement the report as AAD does not hold all the properties we need. So I am reading 1000’s of accounts and mine was just an example.

In my original report I issues a get-aduser for each user I wanted to get additional properties for but this was taking around 900ms per call. I thought it would be quicker to read all users into an array and then read from there.

 

4

What is wrong with the formatting on this site!

It’s chopping off sentences…

5

Update:

I have switched to using a HASH table which fixes the overall performance.