On Thu, Aug 29, 2013 at 1:57 PM, Robert Coli <rc...@eventbrite.com> wrote: > On Thu, Aug 29, 2013 at 10:49 AM, S C <as...@outlook.com> wrote: >> I see a high count "All time blocked" for Flush Writer on nodetool tpstats. >> >> Is it how many blocked ever since the server was online? Can somebody >> explain me what it is? I really appreciate it. > > > Yes. > > Flush Writer thread pool is the thread pool responsible for the part of > memtable flush that actually writes to disk. > If you see it with a non-zero blocked number, you have at some time written > to memory significantly faster than you > could flush to disk.
I don't think this is strictly true? There's also the periodic flush that can cause a storm of flushes if you have multiple column families. I sent out a query to the list last week on this topic but didn't get any responses -- I'm very interested in this topic as I've had to set my queue size fairly large to avoid this issue. Ken
