17.2.2: render cached clips mostly lost across app restarts

Need some help with this one - Resolve 17.2.2 Build 4, Win10 Pro x64, Ryzen 3950x (16C/32T), 64GB, RTX 3080.

I didn't use the render cache until recently. but now heavily rely on it due to complex grades (like 1fps renders) - but on every app restart, about 70-80% of my cached clips are lost and need to be re-cached.

All source footage is on an internal hard disk. The cache lives on a dedicated internal SSD. I cache the entire timeline, save project, restart the app = 70-80% of the clips are no longer cached.

I can't find any reason or pattern for this, but it happens every time. I've tried deleting the entire cache inside Resolve, as well as the entire CacheClip folder on my SSD, no change. The cache SSD has hundreds of GB left.

What can cause this?

The Cache drive is first on the list under Preferences>System>Media Storage?

Yes it is. Here the timeline is fully cached:

cache_before.jpg (135.02 KiB) Viewed 726 times

CTRL-S, and exit Resolve.

Restart Resolve, a lot of clips no longer cached (though it's been worse in the past):

cache_after.jpg (122.27 KiB) Viewed 726 times

OK.

That's not normal. I've seen the occasional report on this, but...I don't know what else to suggest here. It may be a bug in Resolve.

OK.

That's not normal. I've seen the occasional report on this, but...I don't know what else to suggest here. It may be a bug in Resolve.

I wonder if my project is corrupt. It was started in 2019, were we on R15 then? And I was running many beta versions since then.

I have found some definite bugs with some clips. I work with stereoscopic 3D, and found that the 'Floating Window' was enabled on some clips (causing an edge to be cropped off), and could not be fixed via its UI - only resetting the grade (and then re-applying it without Floating Window) fixed it.

So I'm wondering if there are other bugs in the project, perhaps when it was saved from older/bugged/beta versions, which are causing this?

I wouldn't suspect that myself as I do the same (excepting the 3D part). And I don't recall seeing anyone report difficulties finishing such projects. It seems to be more of an annoyance than anything.

I have reported this behavior repeatedly, in my case it seems to happen on timelines in older projects and persists even if I copy paste the timelines into a new project.

This is a consistent behaviour. Not a show stopper, but the render cache has been in need of attention for some time.

This is a consistent behaviour. Not a show stopper, but the render cache has been in need of attention for some time.

Hmm. I think it's time for a critical bug fix period, before adding ever more features. these are the basics that need to work, or they're pointless to have at all.

[Rohit Singhal]

Hi George - is this issue specific to a project for you? Can you share such a project with us? Also the captured logs after you reopen Resolve and see render cache disappeared.

Hi George - is this issue specific to a project for you? Can you share such a project with us? Also the captured logs after you reopen Resolve and see render cache disappeared.

Hi Rohit, I've only started using using the render cache recently with my current project, but this project was started on (I believe) R15, so I'm sure it's been corrupted along the way. It behaves in other strange ways, including frequently massively overflowing virtual memory (170GB+) when the User cache is enabled.

I'll send you a DM with it & the logs later today or tomorrow. I'll build the entire cache, copy the logs, and then restart the app and include those logs too.

BTW I'm collecting and reporting a growing list of bugs. I've reported most to support-usa@blackmagicdesign.com recently, but if there's a more direct contact to your devs that would be awesome (I work with stereo 3D and found lots of issues there too). I'm a programmer and long time beta tester for various people.

I also wonder if my issues are specific to stereo 3D clips (although some cache fine).