I would also optimize for your worst case, which is hitting zero caches. If you're using the default settings when creating a table, you're going to get compression settings that are terrible for reads. If you've got memory to spare, I suggest changing your chunk_length_in_kb to 4 and disabling readahead on your drives entirely. I've seen 50-100x improvement in read latency and throughput just by changing those settings. I just did a talk on this topic last week, slides are here: https://www.slideshare.net/JonHaddad/performance-tuning-86995333
Jon On Wed, Jul 12, 2017 at 2:03 PM Jeff Jirsa <jji...@apache.org> wrote: > > > On 2017-07-12 12:03 (-0700), Fay Hou [Storage Service] < > fay...@coupang.com> wrote: > > First, a big thank to Jeff who spent endless time to help this mailing > list. > > Agreed that we should tune the key cache. In my case, my key cache hit > rate > > is about 20%. mainly because we do random read. We just going to leave > the > > index_interval as is for now. > > > > That's pretty painful. If you can up that a bit, it'll probably help you > out. You can adjust the index intervals, too, but I'd significantly > increase key cache size first if it were my cluster. > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org > For additional commands, e-mail: user-h...@cassandra.apache.org > >
