[GitHub] [incubator-druid] leerho commented on issue #7337: DataSketches HLL is not a replacement for Cardinality aggregator

[GitBox <gi...@apache.org>]

leerho commented on issue #7337: DataSketches HLL is not a replacement for Cardinality aggregator
URL: https://github.com/apache/incubator-druid/issues/7337#issuecomment-479351657
 
 
   There is some confusion here ... the DataSketches (DS) HllSketch is a wee
   bit slower on update than the Theta Sketch and noticeably slower on merge
   (but still quite fast). However, the Theta Sketch can be used in set
   operations while the HllSketch cannot.  For that capability, however, the
   Theta Sketch is about 10X bigger in size.
   
   The principal reason for the HllSketch is it’s small size.
   
   
   On Fri, Mar 29, 2019 at 9:28 PM pdeva <no...@github.com> wrote:
   
   > @jon-wei <https://github.com/jon-wei> looking at the Theta sketch, can't
   > it basically do everything HLL sketch can do?
   > Is the HLL sketch just faster than Theta sketch but covers less use cases?
   >
   > Ie, is it correct to say HLL is a subset of Theta sketch in terms of
   > features, but we include it cause its faster?
   >
   > —
   > You are receiving this because you are subscribed to this thread.
   > Reply to this email directly, view it on GitHub
   > <https://github.com/apache/incubator-druid/issues/7337#issuecomment-478205887>,
   > or mute the thread
   > <https://github.com/notifications/unsubscribe-auth/AMV4wtIkNw8KivKXJdwu0i2iNOfj4Eyrks5vbufUgaJpZM4cGM3E>
   > .
   >
   -- 
   From my cell phone.
   

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For additional commands, e-mail: commits-help@druid.apache.org