Thanks/Shukran, Jon! :) Wouldn't this make Writes disk-bound then? I think the documentation may have been a bit misleading then "Insert-heavy workloads will actually be CPU-bound in Cassandra before being memory-bound"?
On Sat, Jul 20, 2013 at 12:12 PM, Jonathan Haddad <jonathan.had...@gmail.com > wrote: > Everything is written to the commit log. In the case of a crash, cassandra > recovers by replaying the log. > > > On Sat, Jul 20, 2013 at 9:03 AM, Mohammad Hajjat <haj...@purdue.edu>wrote: > >> Patricia, >> >> Thanks for the info. So are you saying that the *whole* data is being >> written on disk in the commit log, not just some sort of a summary/digest? >> I'm writing 10MB objects and I'm noticing high latency (250 milliseconds >> even with ANY consistency), so I guess that explains my high delays? >> >> Thanks, >> Mohammad >> >> >> On Fri, Jul 19, 2013 at 2:17 PM, Patricia Gorla <gorla.patri...@gmail.com >> > wrote: >> >>> Kanwar, >>> >>> This is because writes are appends to the commit log, which is stored on >>> disk, not memory. The commit log is then flushed to the memtable (in >>> memory), before being written to an sstable on disk. >>> >>> So, most of the actions in sending out a write are writing to disk. >>> >>> Also see: http://www.datastax.com/docs/1.2/dml/about_writes >>> >>> Patricia >>> >>> >>> On Fri, Jul 19, 2013 at 1:05 PM, Kanwar Sangha <kan...@mavenir.com>wrote: >>> >>>> “Insert-heavy workloads will actually be CPU-bound in Cassandra >>>> before being memory-bound”**** >>>> >>>> ** ** >>>> >>>> Can someone explain why the internals of why writes are CPU bound ?**** >>>> >>>> ** ** >>>> >>>> ** ** >>>> >>> >>> >> >> >> -- >> *Mohammad Hajjat* >> *Ph.D. Student* >> *Electrical and Computer Engineering* >> *Purdue University* >> > > -- *Mohammad Hajjat* *Ph.D. Student* *Electrical and Computer Engineering* *Purdue University*
