Import-CSV has very high filesize-to-memory consumption ratio of around 50 #7603
Description
Steps to reproduce
Importing a 150 MB CSV file with 50k rows, 700 columns and 5 +/- 3 characters per entry results in a memory consumption of 7GB of the PowerShell process. This is a ratio of around 50 when compared to the file size. I have seen this ratio also with a similar file of smaller size (1.5MB) and therefore think this is a more generic issue not specific to the CSV file structure itself.
$csv = Import-Csv $pathToCsvFiileNote that this does not happen if I do not assign to a variable or pipe to Out-Null
Expected behavior
Filesize to memory ratio is reasonable (around 10)
Actual behavior
Filesize to memory ratio is around 50
Environment data
Latest daily build and RC1
> $PSVersionTable
Name Value
---- -----
PSVersion 6.1.0-preview.761
PSEdition Core
GitCommitId 6.1.0-preview.761
OS Microsoft Windows 6.3.9600
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0
Name Value
---- -----
PSVersion 6.1.0-rc.1
PSEdition Core
GitCommitId 6.1.0-rc.1
OS Microsoft Windows 6.3.9600
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0