While I am actually +1 on LCS being default as it handles more use cases well compared to STCS. I am -1 on UCS being default anywhere currently, the UX is horrible, documentation is unreadable and it's only available on a release barely anyone uses yet (not adequately tested in production). Seems like there's quite a bit of disagreement here.
On Fri, Dec 6, 2024 at 9:30 PM Brad <bscho...@gmail.com> wrote: > I'm -1 on LCS being the default, seen far too many people use it for disk > storage management > > On Fri, Dec 6, 2024 at 10:08 PM Jon Haddad <j...@rustyrazorblade.com> > wrote: > >> I'm -1 on LCS being the default, since using it in the wrong situations >> renders clusters inoperable. >> >> >> On Fri, Dec 6, 2024 at 7:03 PM Paulo Motta <pa...@apache.org> wrote: >> >>> > I'd prefer to see the default go from STCS to UCS >>> >>> I’m proposing this for latest unstable (cassandra_latest.yaml) since >>> it’s a more recent strategy still being adopted. For latest stable >>> (cassandra.yaml) I’d prefer LCS since it does not need tuning to support >>> mutable workloads (UPDATE/DELETE) and is battle-tested. >>> >>> On Fri, 6 Dec 2024 at 21:37 Jon Haddad <j...@rustyrazorblade.com> wrote: >>> >>>> I'd prefer to see the default go from STCS to UCS, probably with >>>> scaling_parameters T4. That's essentially the same as STCS but without the >>>> ridiculous SSTable growth, allowing us to leverage the fast streaming path >>>> more often. I don't think there's any valid use cases for STCS anymore now >>>> that we have UCS. >>>> >>>> That said, many have taken issue with the state of UCS docs, myself >>>> included, so that would need to be addressed with any default change. >>>> >>>> I don't think we should mark TWCS as experimental. Maybe we prevent >>>> repairs to tables using TWCS, or do a better job of encouraging folks to >>>> use incremental repair at higher frequencies. It's definitely not >>>> experimental though. >>>> >>>> Side note: I think experimental has been over-used and has lost all >>>> meaning. How is Java 17 experimental? Very confusing for the community. >>>> >>>> I think TWCS should use UCS under the hood which would address >>>> streaming performance (and thus node density) or UCS could be updated to >>>> allow for time window's options. Either would solve issue #3 in your list. >>>> >>>> Jon >>>> >>>> >>>> >>>> On Fri, Dec 6, 2024 at 5:36 PM Paulo Motta <pa...@apache.org> wrote: >>>> >>>>> Hi, >>>>> >>>>> It’s 2024 and users are still facing issues due to misconfigured >>>>> compaction when using default configuration. >>>>> >>>>> I would like to start a conversation around improving compaction >>>>> defaults in 5.1/trunk, so users trying out CQL transactions don’t need to >>>>> worry about tuning compaction. >>>>> >>>>> A few suggestions: >>>>> >>>>> 1) Make LeveledCompactionStrategy default on cassandra.yaml, UCS >>>>> default on cassandra_latest.yaml ? >>>>> >>>>> 2) Does TWCS work out of the box with repairs and hints? My >>>>> understanding is that due to CASSANDRA-10496 this causes droppable >>>>> tombstone issues when in combination with repair and hints (see more on >>>>> this thread [1]). We should either fix this or mark TWCS experimental. >>>>> >>>>> 3) When STCS is used with deletions/TTL, tombstones accumulate in >>>>> higher level stables when unchecked_tombstone_compaction is disabled (see >>>>> CASSANDRA-6563). I propose having adding a new setting “auto” enabled by >>>>> default that will have this set to true when STCS/TWCS is used. >>>>> >>>>> I believe addressing these points will improve user experience with >>>>> Cassandra. >>>>> >>>>> I apologize in advance if these topics were discussed in recent >>>>> threads. I would be happy to get pointers of related discussions on this >>>>> topic. >>>>> >>>>> I will be happy to create JIRA if there’s agreement on addressing >>>>> these items. >>>>> >>>>> Thanks, >>>>> >>>>> Paulo >>>>> >>>>> [1] - >>>>> >>>>> https://user.cassandra.apache.narkive.com/VQOacfnT/twcs-repair-create-new-buckets-with-old-data >>>>> >>>>
