WarmDynamicSecurityCache.ps1

<#
.SYNOPSIS
    Warms the SSAS permissions when using a dynamic security role
.NOTES
    Author: Darren Gosbell 
    Date:   6 Jul 2016
 .DESCRIPTION
    Warms the Global Scope cache for a list of users. This is useful when
    the first connection on a cold cache per user is slow due to evaluation
    of a dynamic security role. For production usage it would make sense
    to get the list of user accounts by running a SQL query against your
    user security table rather than hard coding it.
    
    NOTE: MUST be run by an account with SSAS Server admin priviledges
#> 

## the following 4 variables need to be updated for your environment
$server = "localhost\tab12"
$database = "AW Internet Sales Tabular Model 2014"
$model = "Model"
$users = @(
"mydomain\user1",
"mydomain\user2"
)

$userCnt = 0
[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.AnalysisServices.adomdclient") > $NULL

foreach ($user in $users) {
    $userCnt++
    $connStr = "data source=$server;initial catalog=$database;EffectiveUserName=$user" 
    $cnn = new-object Microsoft.AnalysisServices.adomdclient.adomdconnection($connStr)
    $cmd = $cnn.CreateCommand()
    $cmd.CommandText = "select {} on 0 FROM [$model]"
    $da = new-Object Microsoft.AnalysisServices.AdomdClient.AdomdDataAdapter($cmd)
    $ds = new-Object System.Data.DataSet
    $da.Fill($ds) > $NULL
    $cnn.Close()
    write-output "cache primed for user: $user"
    Write-Progress -Status "Priming User Caches" -Activity "User: $user" -PercentComplete (($userCnt / $users.Count) * 100)
}

thanks a lot for your detailed explanation.