That should never need to happen in UCS as far as I understand. Levels should be defined by the properties of the sstable, not by assignment, so all sstables should be placed in the correct bucket on creation by definition. I haven’t read the code though, so there might be some impediment to that platonic ideal. Branimir can confirm, but this *should* naturally fall out of the formalisation.
> On 9 Dec 2024, at 14:27, Jeff Jirsa <jji...@apache.org> wrote: > > > > On 2024/12/09 17:33:09 Benedict wrote: >> I think it would make sense to support overriding the default FP in the UCS >> parameters, so we can treat it as a direct replacement. Desiree FP is >> directly related to sstable overlaps after all. >> >> Can you think of any other usability gaps like this? > > Without reading the code, the only other one that comes to mind is single > sstable upleveling in LCS. > > (The UCS docs talk about trying to forecast when to push sstables one extra > level, but we saw in it's often the case that you can breach the fanout > without any real overlaps, and simply re-leveling via metadata mutation could > maintain that invariant easier than rewriting the whole table. It's possible > UCS is doing this, too, but again, not obvious in the docs.)
