yes, agree, I had them the wrong way around in my pseudo code.

Those look like they are round the wrong way

offset_t compressedSize = file->size():
offset_t uncompressedSize = io->size():

Talked with @Jacob Cobbett-Smith, I may find out the compressed size for each file part using the createCompressedFileReader:

{{Owned<IFile> file = ...
Owned<IFileIO> io = createCompressedFileReader(.

offset_t uncompressedSize = file->size():
offset_t compressedSize = io->size():}}

Is the compressed size for a logical file the summary of the compressed sizes of its physical parts?

@Kanghua Wang - can you look at implementing this?

ok yes, I was just testing, 😉 I'd clearly forgotten how this worked.

In that case, as you originally suggested, the publish can inspect the file parts, and gather both the compressed and uncompressed sizes and populate that info. into the logical file meta data.