Got it. Thanks again.
> On Jan 20, 2018, at 11:17 AM, Alexander Dejanovski <a...@thelastpickle.com> > wrote: > > I would turn background read repair off on the table to improve the overlap > issue, but you'll still have foreground read repair if you use quorum reads > anyway. > > So put dclocal_... to 0.0. > > The commit you're referring to has been merged in 3.11.1 as 2.1 doesn't > patched anymore. > > >> Le sam. 20 janv. 2018 à 16:55, Brian Spindler <brian.spind...@gmail.com> a >> écrit : >> Hi Alexander, after re-reading this >> https://issues.apache.org/jira/browse/CASSANDRA-13418 it seems you would >> recommend leaving dclocal_read_repair at maybe 10% is that true? >> >> Also, has this been patched to 2.1? >> https://github.com/thelastpickle/cassandra/commit/58440e707cd6490847a37dc8d76c150d3eb27aab#diff-e8e282423dcbf34d30a3578c8dec15cdR176 >> >> >> Cheers, >> >> -B >> >> >>> On Sat, Jan 20, 2018 at 10:49 AM Brian Spindler <brian.spind...@gmail.com> >>> wrote: >>> Hi Alexander, Thanks for your response! I'll give it a shot. >>> >>>> On Sat, Jan 20, 2018 at 10:22 AM Alexander Dejanovski >>>> <a...@thelastpickle.com> wrote: >>>> Hi Brian, >>>> >>>> You should definitely set unchecked_tombstone_compaction to true and set >>>> the interval to the default of 1 day. Use a tombstone_threshold of 0.6 for >>>> example and see how that works. >>>> Tombstones will get purged depending on your partitioning as their >>>> partition needs to be fully contained within a single sstable. >>>> >>>> Deleting the sstables by hand is theoretically possible but should be kept >>>> as a last resort option if you're running out of space. >>>> >>>> Cheers, >>>> >>>> >>>>> Le sam. 20 janv. 2018 à 15:41, Brian Spindler <brian.spind...@gmail.com> >>>>> a écrit : >>>>> I probably should have mentioned our setup: we’re on Cassandra version >>>>> 2.1.15. >>>>> >>>>> >>>>>> On Sat, Jan 20, 2018 at 9:33 AM Brian Spindler >>>>>> <brian.spind...@gmail.com> wrote: >>>>>> Hi, I have several column families using TWCS and it’s great. >>>>>> Unfortunately we seem to have missed the great advice in Alex’s article >>>>>> here: http://thelastpickle.com/blog/2016/12/08/TWCS-part1.html about >>>>>> setting the appropriate aggressive tombstone settings and now we have >>>>>> lots of timestamp overlaps and disk space to reclaim. >>>>>> >>>>>> I am trying to figure the best way out of this. Lots of the SSTables >>>>>> with overlapping timestamps in newer SSTables have droppable tombstones >>>>>> at like 0.895143957 or something similar, very close to 0.90 where the >>>>>> full sstable will drop afaik. >>>>>> >>>>>> I’m thinking to do the following immediately: >>>>>> >>>>>> Set unchecked_tombstone_compaction = true >>>>>> Set tombstone_compaction_interval == TTL + gc_grace_seconds >>>>>> Set dclocal_read_repair_chance = 0.0 (currently 0.1) >>>>>> >>>>>> If I do this, can I expect TWCS/C* to reclaim the space from those >>>>>> SSTables with 0.89* droppable tombstones? Or do I (can I?) manually >>>>>> delete these files and will c* just ignore the overlapping data and >>>>>> treat as tombstoned? >>>>>> >>>>>> What else should/could be done? >>>>>> >>>>>> Thank you in advance for your advice, >>>>>> >>>>>> __________________________________________________ >>>>>> Brian Spindler >>>>>> >>>>>> >>>> >>>> -- >>>> ----------------- >>>> Alexander Dejanovski >>>> France >>>> @alexanderdeja >>>> >>>> Consultant >>>> Apache Cassandra Consulting >>>> http://www.thelastpickle.com > > -- > ----------------- > Alexander Dejanovski > France > @alexanderdeja > > Consultant > Apache Cassandra Consulting > http://www.thelastpickle.com
