fileorder takes too long

[JobWellDone]

I have folder with 500 ARW raw files about 15 MB each image.

When i run exiftool with -progress flag it starts in few seconds and i see processing files, however if i run same command with adding  -fileorder filename flag then file progress starts to show in like 3-5 minutes after executing exiftool.

Why fileorder is so slow?

[StarGeek]

From the docs on the -FileOrder option
     Note that the -fileOrder option can incur large performance penalty since it involves an additional initial processing pass of all files, but this impact may be reduced by specifying a NUM to effectively set the -fast level for the initial pass. For example, -fileOrder4 may be used if TAG is a pseudo System tag.

So using -FileOrder means that exiftool has to read through all the files once to collect the data for sorting, then once more for the actual processing.

As the docs say, when using a system tag such as Filename, adding a 4 will speed things up.

[wywh]

I currently add '-fileOrder5 FileName' to the command if I want a macOS APFS-formatted volume to display the the output sorted by filenames (the old MacOS Extended format does not need this).