For mount sftp,why right click on exe file is so slow until it freezes

[Ole (Ole Frost)]

Great example, illustration and debug log!

I have made the same observations as Nick, who probably thinks you are using SFTP (from the thread heading).

I do however know that you are using S3 (Wasabi), so I feel pretty sure you will see much better responsiveness by adding --vfs-fast-fingerprint:

If you are running a vfs cache over local , s3 or swift backends then using this flag is recommended.

Source: https://rclone.org/commands/rclone_mount/#fingerprinting

Perhaps @ncw can give a quick rundown of the drawbacks/risks.

@ncw

The OS seems to read bits out of the first 32k 8 times! This isn't a problem it should be cached after the first read. It reads another 32k 3 times also.

As the reads are relatively close together you can see rclone just streams the first 900k of the file.

Agree, Windows reads the same app. 35K several times. And the 35K comes from different parts of the file so 2-3 reads of the minimum buffer size (32768) from the remote is to be expected.

It does however puzzle me why rclone decides to stream the first 900k of the file, can you briefly give me a hint?

@ncw

This means that the file bits are in cache very quickly - see the present = true here. Everything is in cache at 02:48:08 (when the read above finished) so <1 second after starting but the OS wasn't done with the file until 02:48:16 so there are 8 seconds of overhead.

You see two actions in the log: The file is selected at 02:48:08 and Windows checks something (icon) behind the scenes. The right-click is happening at 02:48:12 and may be a combined select and right-click, driving the number of requests up. It takes 4 seconds with all content loaded from cache, so really only checking the fingerprint 13 times - 300ms per fingerprint.

@ncw

If it is, I don't think it would be unreasonable to cache these fingerprints. Exactly for how long I don't know but somewhere around --dir-cache-time maybe. Or maybe with its own parameter.

Might be a very good idea to better support applications with high appetite on rapidly sniffing small parts of (executable) files.

However, not sure I understand the fingerprinting method and usage in relation to mounts well enough to comment on the best approach. Do we have a description of rclone's finger printing and especially the method used by --vfs-fast-fingerprint? something between the above link and the code (docs, forum posts, ...)