fix file modification date comparisons #14503
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On filesystems like ZFS with higher modification time accuracy than the database, the comparison itemLastModifiedFileSystem != modificationDate fails. Allow a tolerance of 1 second.
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I wouldn't mind merging this but I use ZFS too and never had any issue with this while testing before and after we released the RCs. |
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I never noticed this until I put 40k music tracks into Jellyfin and found scans took all day and reprocessed all media. With debugging enabled I recorded logs like: [08:42:41] [DBG] [31] MediaBrowser.Providers.TV.EpisodeMetadataService: File modification time changed from 03/12/2025 13:14:21 to 03/12/2025 13:14:21: With the changes a library scan takes a few minutes. |
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But |
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The problem was on all my media and that episode happened to be the one I chose to reference in the jellyfin developer chat, so I had a record of it in the chat to give here. |
Emby.Photos/PhotoProvider.cs
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| @@ -49,7 +49,7 @@ public bool HasChanged(BaseItem item, IDirectoryService directoryService) | |||
| if (item.IsFileProtocol) | |||
| { | |||
| var file = directoryService.GetFile(item.Path); | |||
| return file is not null && file.LastWriteTimeUtc != item.DateModified; | |||
| return file is not null && item.DateModified.Subtract(file.LastWriteTimeUtc).Duration().TotalSeconds > 1; | |||
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This is copied in so many places now that I think it warrants an extension/utility method.
FileService will return whatever with whatever accuracy on a given platform, the database will return with whatever accuracy on a given platform, and Jelly should not care as long as the file modification date is sufficiently different for its purposes. For this change "sufficiently different" was chosen to be 1 second, but there is existing code in Jelly that works the same way for "sufficiently different" being 1 day instead (for once per day updates). It just can't directly compare fileModified == databaseModified, just like floating point values can't be directly compared with == because floating point accuracy can vary. The code is simple and robust; if we are worried about it being ugly, it could easily be done as a helper function (e.g. if fileChanged(databaseModified, fileModified, accuracySeconds = 1) { } and then is also usable in those cases using a 1 day resolution. |
Changes
On filesystems like ZFS with higher modification time accuracy than the database, the comparison itemLastModifiedFileSystem != modificationDate fails. Allow a tolerance of 1 second.
Issues
No issue raised. On ZFS causes every file to be rescanned on every scan run.