如果需要加快执行一个脚本,你可能需要用到后台作业。后台作业能同时运行脚本中多个事件。
Powershell是单线程程序且一次只能做一件事情。后台作业能额外增加Powershell进程在后台处理作业。当需要程序同时运行且数据量不是很大时它能很好的解决问题。但从Powershell后台回传数据是一个非常麻烦的工作,它将浪费很多时间。将会导致脚本更慢。
这里有3个并发执行任务:
$start = Get-Date # get all hotfixes $task1 = { Get-Hotfix } # get all scripts in your profile $task2 = { Get-Service | Where-Object Status -eq Running } # parse log file $task3 = { Get-Content -Path $env:windir\windowsupdate.log | Where-Object { $_ -like '*successfully installed*' } } # run 2 tasks in the background, and 1 in the foreground task $job1 = Start-Job -ScriptBlock $task1 $job2 = Start-Job -ScriptBlock $task2 $result3 = Invoke-Command -ScriptBlock $task3 # wait for the remaining tasks to complete (if not done yet) $null = Wait-Job -Job $job1, $job2 # now they are done, get the results $result1 = Receive-Job -Job $job1 $result2 = Receive-Job -Job $job2 # discard the jobs Remove-Job -Job $job1, $job2 $end = Get-Date Write-Host -ForegroundColor Red ($end - $start).TotalSeconds
上面执行全部的任务消耗了5.9秒。三个任务的结果将分别存入$result1, $result2, 和 $result3.
让我们再继续查看相继在前台执行完命令需要多长时间:
$start = Get-Date # get all hotfixes $task1 = { Get-Hotfix } # get all scripts in your profile $task2 = { Get-Service | Where-Object Status -eq Running } # parse log file $task3 = { Get-Content -Path $env:windir\windowsupdate.log | Where-Object { $_ -like '*successfully installed*' } } # run them all in the foreground: $result1 = Invoke-Command -ScriptBlock $task1 $result2 = Invoke-Command -ScriptBlock $task2 $result3 = Invoke-Command -ScriptBlock $task3 $end = Get-Date Write-Host -ForegroundColor Red ($end - $start).TotalSeconds
结果,这次只花费了5.05秒。与后台作业几乎同时完成,所以后台作业更适合解决长时间执行的任务。从三个任务返回的数据观察,好处是这种按顺数在前台获得数据能减少了执行过程的开销。
原文地址:Parallel Processing in PowerShell
本文链接: https://www.pstips.net/parallel-processing-in-powershell.html
请尊重原作者和编辑的辛勤劳动,欢迎转载,并注明出处!
请尊重原作者和编辑的辛勤劳动,欢迎转载,并注明出处!