BLoom filters... nevermind
On Thu, Feb 22, 2018 at 4:48 PM, Carl Mueller <carl.muel...@smartthings.com> wrote: > Is the current reason for a large starting heap due to the memtable? > > On Thu, Feb 22, 2018 at 4:44 PM, Carl Mueller < > carl.muel...@smartthings.com> wrote: > >> ... compaction on its own jvm was also something I was thinking about, >> but then I realized even more JVM sharding could be done at the table level. >> >> On Thu, Feb 22, 2018 at 4:09 PM, Jon Haddad <j...@jonhaddad.com> wrote: >> >>> Yeah, I’m in the compaction on it’s own JVM camp, in an ideal world >>> where we’re isolating crazy GC churning parts of the DB. It would mean >>> reworking how tasks are created and removal of all shared state in favor of >>> messaging + a smarter manager, which imo would be a good idea regardless. >>> >>> It might be a better use of time (especially for 4.0) to do some GC >>> performance profiling and cut down on the allocations, since that doesn’t >>> involve a massive effort. >>> >>> I’ve been meaning to do a little benchmarking and profiling for a while >>> now, and it seems like a few others have the same inclination as well, >>> maybe now is a good time to coordinate that. A nice perf bump for 4.0 >>> would be very rewarding. >>> >>> Jon >>> >>> > On Feb 22, 2018, at 2:00 PM, Nate McCall <zznat...@gmail.com> wrote: >>> > >>> > I've heard a couple of folks pontificate on compaction in its own >>> > process as well, given it has such a high impact on GC. Not sure about >>> > the value of individual tables. Interesting idea though. >>> > >>> > On Fri, Feb 23, 2018 at 10:45 AM, Gary Dusbabek <gdusba...@gmail.com> >>> wrote: >>> >> I've given it some thought in the past. In the end, I usually talk >>> myself >>> >> out of it because I think it increases the surface area for failure. >>> That >>> >> is, managing N processes is more difficult that managing one process. >>> But >>> >> if the additional failure modes are addressed, there are some >>> interesting >>> >> possibilities. >>> >> >>> >> For example, having gossip in its own process would decrease the odds >>> that >>> >> a node is marked dead because STW GC is happening in the storage JVM. >>> On >>> >> the flipside, you'd need checks to make sure that the gossip process >>> can >>> >> recognize when the storage process has died vs just running a long GC. >>> >> >>> >> I don't know that I'd go so far as to have separate processes for >>> >> keyspaces, etc. >>> >> >>> >> There is probably some interesting work that could be done to support >>> the >>> >> orgs who run multiple cassandra instances on the same node (multiple >>> >> gossipers in that case is at least a little wasteful). >>> >> >>> >> I've also played around with using domain sockets for IPC inside of >>> >> cassandra. I never ran a proper benchmark, but there were some >>> throughput >>> >> advantages to this approach. >>> >> >>> >> Cheers, >>> >> >>> >> Gary. >>> >> >>> >> >>> >> On Thu, Feb 22, 2018 at 8:39 PM, Carl Mueller < >>> carl.muel...@smartthings.com> >>> >> wrote: >>> >> >>> >>> GC pauses may have been improved in newer releases, since we are in >>> 2.1.x, >>> >>> but I was wondering why cassandra uses one jvm for all tables and >>> >>> keyspaces, intermingling the heap for on-JVM objects. >>> >>> >>> >>> ... so why doesn't cassandra spin off a jvm per table so each jvm >>> can be >>> >>> tuned per table and gc tuned and gc impacts not impact other tables? >>> It >>> >>> would probably increase the number of endpoints if we avoid having an >>> >>> overarching query router. >>> >>> >>> > >>> > --------------------------------------------------------------------- >>> > To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org >>> > For additional commands, e-mail: dev-h...@cassandra.apache.org >>> > >>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org >>> For additional commands, e-mail: dev-h...@cassandra.apache.org >>> >>> >> >
