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 <[email protected]> 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 <[email protected]> > 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
