[VOTE]: Add files to IndexMetadata

[wjones127]

We can add a message to the IndexMetadata:

message IndexMetadata {
    repeated IndexFile index_files = 10;
}

message IndexFile {
    // Path relative to UUID directory.
    string path = 1;
    int64 size = 2;
}

This gives us the exact size of the files within the index, which provides two benefits:

• Cold read performance: the index reader can skip the initial HEAD call to find the footer, if we store the size of the index file.
• Makes index size stats available: We could report the on-disk size of the index in statistics, without having to open the index.

Original discussion here: #5456

Format changes PR: #5545

Implementation draft PR: #5497

Vote can close on January 27, 2026 at noon PT.

[jackye1995]

+1 (binding)

[Xuanwo]

+1 binding

[wjones127]

+1 (binding)

[westonpace]

+1 (binding)

[wjones127]

✅ This vote has passed with four binding votes. We will move forward with the format change PR #5545 and then finish up the library changes.