On Thu, Feb 18, 2010 at 12:58 AM, Erik Rozendaal <dlrozend...@gmail.com> wrote: > We're getting about 2500 gets/sec max per regionserver when it serves data > from the block cache using HBase 0.20.3. All data is in the same region and > the region has just one store file for the family we're querying. HBASE-2180 > didn't seem to help here.
HBASE-2180 is about concurrency getting at files over in hdfs. It will have no effect on data being read form memstores. At this point the region server is using about 1.5 cores. Since we have 8 cores available the bottleneck does not seem to be CPU. > > The number of clients does not seem to matter (we tested with 1-4 clients). > > The only other bottleneck that I can think of is network, but we test on a > local 1 Gbit LAN. Our web server can handle 15,000 requests/sec, so that > doesn't seem to be the case. > > Maybe there is some synchronization going limiting the CPU scalability of a > single region server? It would seem so. Let me make an issue to profile it (Any chance of you wanting to dig in?). It might be the row lock but if you are getting same numbers whether 1 or 4 clients, it would seem to say no? Thanks Erik. St.Ack > > Regards, > Erik > > > On 17 feb 2010, at 20:44, Brad McCarty wrote: > >> I don't really have any idea yet what that request rate would be that would >> overwhelm a single RS; I assume the CPU overhead to server from cache is >> pretty small so it'd have to be a very high rate. >> >> I was originally more concerned about the aggregate CPU utilization on the >> RS caused by both connection management and cache serving, but if we have >> connection pools per Tomcat server that's less of a concern now. >> >> We're looking a serving a eCommerce catalog from HBase and our data access >> patterns won't be as random as some of the examples I've seen of other >> production sites using HBase, hence the concern. >> >> We'll know more in the next couple of weeks. >> >> Brad >> >> >> On Feb 17, 2010, at 11:36 AM, Stack wrote: >> >>> On Wed, Feb 17, 2010 at 11:27 AM, Brad McCarty <mcca...@gmail.com> wrote: >>>>> This is hbase. You don't buy bigger hardware, you just add nodes (smile). >>>> >>>> >>>> Not sure if that was tongue-in-cheek, because adding nodes wouldn't >>>> address the hot row issue would it?? >>>> >>> >>> Yes. I was trying to do tongue-in-cheek but, yes, you are right, it >>> would not address the hot row issue (I misread). >>> >>> What kind of request rate are you thinking would overwhelm serving a >>> row from cache? >>> >>> St.Ack >> > >
