RE: Question about CL.ZERO

2010-07-12 Thread Todd Burruss
and forget" type of events. maybe the risk of overloading a server is not worth it. From: Benjamin Black [...@b3k.us] Sent: Monday, July 12, 2010 3:50 PM To: user@cassandra.apache.org Subject: Re: Question about CL.ZERO CL.ONE represents the fastest

Re: Question about CL.ZERO

2010-07-12 Thread Benjamin Black
CL.ONE represents the fastest you can sustain. CL.ZERO represents writing to memory on the coordinator, regardless of what the nodes can sustain for durable writes. That is a bad situation, regardless of your durability goals. So, there is no good reason. What you are describing is a non-existe

Re: Question about CL.ZERO

2010-07-12 Thread Aaron Morton
My understanding is that the coordinator will acknowledge the writes faster then they can actually be written. Eventually it will run out of buffer space. see http://wiki.apache.org/cassandra/FAQ#slows_down_after_lotso_insertsUsing CL.ONE makes it harder for the clients to flood the cluster with mo

Re: Question about CL.ZERO

2010-07-12 Thread B. Todd Burruss
why is there no good reason? if i would like to record informational events, possibly for debugging or something, i don't care if they actually get saved and i want the client's request to be as fast as possibly. this sounds like a good reason. are you saying that CL.ONE is equally performan

Re: Question about CL.ZERO

2010-07-11 Thread Benjamin Black
And, to be clear, there is no good reason to use CL.ZERO and it can be a serious resource hog on the coordinator. On Sun, Jul 11, 2010 at 9:21 AM, ChingShen wrote: > Hi all, > >   Does it mean that the coordinator node always return success to the client > at CL.ZERO? But if the coordinator node

Re: Question about CL.ZERO

2010-07-11 Thread Jonathan Ellis
On Sun, Jul 11, 2010 at 11:21 AM, ChingShen wrote: > Hi all, > >   Does it mean that the coordinator node always return success to the client > at CL.ZERO? Yes. > But if the coordinator node sends a request to a given node > B(RF=1), then B is down, what happened? The coordinator node will write

Question about CL.ZERO

2010-07-11 Thread ChingShen
Hi all, Does it mean that the coordinator node always return success to the client at CL.ZERO? But if the coordinator node sends a request to a given node B(RF=1), then B is down, what happened? The coordinator node will write the hint locally? Thanks. Shen