No, data is hardly ever deleted from this table. The cfstats conform this. The data is also nog reinserted. Op 5 mrt. 2016 6:20 PM schreef "DuyHai Doan" <doanduy...@gmail.com>:
> Maybe tombstones ? Do you issue a lot of DELETE statements ? Or do you > re-insert in the same partition with different TTL values ? > > On Sat, Mar 5, 2016 at 7:16 PM, Tom van den Berge <t...@drillster.com> > wrote: > >> I don't think compression can be the cause of the difference, because of >> two reasons: >> >> 1) The partition size I calculated myself (3 MB) is the uncompressed >> size, and so is the reported size (2.3 GB) >> >> 2) The difference is simply way too big to be explained by compression, >> even if the calculated size would have been the compressed size. The >> compression would be 0.125% of the original, which is not realistic. In the >> logs, I can see that the typical compression that is achieved for this >> table is around 80% of the original. >> >> Tom >> >> On Fri, Mar 4, 2016 at 9:48 PM, Robert Coli <rc...@eventbrite.com> wrote: >> >>> On Fri, Mar 4, 2016 at 5:56 AM, Tom van den Berge <t...@drillster.com> >>> wrote: >>> >>>> Compacting large partition >>>> drillster/subscriberstats:rqtPewK-1chi0JSO595u-Q (1,470,058,292 bytes) >>>> >>>> This means that this single partition is about 1.4GB large. This is >>>> much larger that it can possibly be, because of two reasons: >>>> 1) the partition has appr. 50K rows, each roughly 62 bytes = ~3 MB >>>> 2) the entire table consumes appr. 500MB of disk space on the node >>>> containing the partition (including snapshots) >>>> >>>> Furthermore, nodetool cfstats tells me this: >>>> Space used (live): 253,928,111 >>>> Space used (total): 253,928,111 >>>> Compacted partition maximum bytes: 2,395,318,855 >>>> The space used seem to match the actual size (excl. snapshots), but the >>>> Compacted partition maximum bytes (2,3 GB) seems to be far higher than >>>> possible. Does anyone know how it is possible that Cassandra reports such >>>> unlikely sizes? >>>> >>> >>> Compression is enabled by default, and compaction reports the >>> uncompressed size. >>> >>> =Rob >>> >>> >> >> >> >> -- >> Tom van den Berge >> Lead Software Engineer >> >> [image: Drillster] >> >> Middenburcht 136 >> 3452 MT Vleuten >> Netherlands +31 30 755 53 30 >> www.drillster.com >> >> [image: Follow us on Facebook] Follow us on Facebook >> <https://www.facebook.com/Drillster> >> > >
