From user-return-5386-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Wed May 05 16:09:07 2010 Return-Path: Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: (qmail 70857 invoked from network); 5 May 2010 16:09:07 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 5 May 2010 16:09:07 -0000 Received: (qmail 41513 invoked by uid 500); 5 May 2010 16:09:06 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 41440 invoked by uid 500); 5 May 2010 16:09:06 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 41432 invoked by uid 99); 5 May 2010 16:09:06 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 05 May 2010 16:09:06 +0000 X-ASF-Spam-Status: No, hits=0.0 required=10.0 tests=FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of jbellis@gmail.com designates 74.125.82.172 as permitted sender) Received: from [74.125.82.172] (HELO mail-wy0-f172.google.com) (74.125.82.172) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 05 May 2010 16:08:58 +0000 Received: by wyb32 with SMTP id 32so1644240wyb.31 for ; Wed, 05 May 2010 09:08:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:mime-version:received:in-reply-to :references:from:date:message-id:subject:to:content-type :content-transfer-encoding; bh=F0Bksn9PHtuzJlB5DHEXvTAjNvmknhhtblwi7pnSnyY=; b=Qr3LIdn14g0/tFfuUhNGAU7rLsvTLK0Ksqs+azI+6VWcI8IrhDy9MUEuiDuFS2lTdt W7MCkpkFgzW7VUgzfmAceGHO8t1TYYhng5wyDQca7i2OrWTB+KQaANxLISgikwgjr0sv 12zLSESMFt3axk36JXD6trhrTuvECTJVJmfO8= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type:content-transfer-encoding; b=D5EPQbup/1wwbDYJN2qoSp8c+zOlRIPfzN9Ovg89dXNaQLQncgM/faFMVxoM12+Xhe 15AsYP0IzgP9CJV7qtwS+itBVsANLJVk+Lod4QiGHjJNJ8QkYu1WzSuJM5sMGArL5nA9 gQwxwuSWpIZFzpVIvCnNSxysHUn/jxq3d42S8= Received: by 10.216.89.85 with SMTP id b63mr3101359wef.189.1273075716305; Wed, 05 May 2010 09:08:36 -0700 (PDT) MIME-Version: 1.0 Received: by 10.216.22.10 with HTTP; Wed, 5 May 2010 09:08:16 -0700 (PDT) In-Reply-To: References: <8A606DEA-CB57-4D0B-90C0-FE79B2DE22E9@discovereads.com> From: Jonathan Ellis Date: Wed, 5 May 2010 11:08:16 -0500 Message-ID: Subject: Re: performance tuning - where does the slowness come from? To: user@cassandra.apache.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Virus-Checked: Checked by ClamAV on apache.org - your key cache isn't warm. capacity 17M, size 0.5M, 468083 reads sounds like most of your reads have been for unique keys. - the kind of reads you are doing can have a big effect (mostly number of columns you are asking for). column index granularity plays a role (for non-rowcached reads); so can column comparator (see e.g. https://issues.apache.org/jira/browse/CASSANDRA-1043) - the slow system reads are all on HH rows, which can get very wide (hence, slow to read the whole row, which is what the HH code does). clean those out either by bringing back the nodes it's hinting for, or just removing the HH data files. On Wed, May 5, 2010 at 10:19 AM, Ran Tavory wrote: > I'm still trying to figure out where my slowness is coming from... > By now I'm pretty sure it's the reads are slow, but not sure how to impro= ve > them. > I'm looking at cfstats. Can you say if there are better configuration > options? So far I've used all default settings, except for: > =A0=A0 =A0 > =A0=A0 =A0 =A0 KeysCached=3D"50%"/> > > =A0org.apache.cassandra.locator.RackAwareStrate= gy > =A0=A0 =A0 =A02 > > =A0org.apache.cassandra.locator.EndPointSnitch > =A0=A0 =A0 > > What does a good read latency look like? I was expecting 10ms, however so > far it seems that my KvImpressions read latency is 30ms and in the system > keyspace I have 800ms :( > I thought adding=A0KeysCached=3D"50%" would improve my situation but > unfortunately looks like the hitrate is about 0. I realize that's > application specific, but maybe there are other magic bullets... > Is there something like adding cache to the system keyspace? 800 ms is > pretty bad, isn't it? > See stats below and thanks. > > Keyspace: outbrain_kvdb > =A0=A0 =A0 =A0 =A0Read Count: 651668 > =A0=A0 =A0 =A0 =A0Read Latency: 34.18622328547666 ms. > =A0=A0 =A0 =A0 =A0Write Count: 655542 > =A0=A0 =A0 =A0 =A0Write Latency: 0.041145092152752985 ms. > =A0=A0 =A0 =A0 =A0Pending Tasks: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Column Family: KvImpressions > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0SSTable count: 13 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Space used (live): 23304548897 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Space used (total): 23304548897 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Columns Count: 895 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Data Size: 2108990 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Switch Count: 8 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Read Count: 468083 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Read Latency: 151.603 ms. > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Write Count: 552566 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Write Latency: 0.023 ms. > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Pending Tasks: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache capacity: 17398656 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache size: 567967 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache hit rate: 0.0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Row cache: disabled > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row minimum size: 269 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row maximum size: 54501 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row mean size: 933 > ... > ---------------- > Keyspace: system > =A0=A0 =A0 =A0 =A0Read Count: 1151 > =A0=A0 =A0 =A0 =A0Read Latency: 872.5014448305822 ms. > =A0=A0 =A0 =A0 =A0Write Count: 51215 > =A0=A0 =A0 =A0 =A0Write Latency: 0.07156788050375866 ms. > =A0=A0 =A0 =A0 =A0Pending Tasks: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Column Family: HintsColumnFamily > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0SSTable count: 5 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Space used (live): 437366878 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Space used (total): 437366878 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Columns Count: 14987 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Data Size: 87975 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Switch Count: 2 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Read Count: 1150 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Read Latency: NaN ms. > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Write Count: 51211 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Write Latency: 0.027 ms. > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Pending Tasks: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache capacity: 6 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache size: 4 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache hit rate: NaN > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Row cache: disabled > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row minimum size: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row maximum size: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row mean size: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Column Family: LocationInfo > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0SSTable count: 2 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Space used (live): 3504 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Space used (total): 3504 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Columns Count: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Data Size: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Memtable Switch Count: 1 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Read Count: 1 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Read Latency: NaN ms. > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Write Count: 7 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Write Latency: NaN ms. > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Pending Tasks: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache capacity: 2 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache size: 1 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Key cache hit rate: NaN > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Row cache: disabled > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row minimum size: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row maximum size: 0 > =A0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Compacted row mean size: 0 > > On Tue, May 4, 2010 at 10:57 PM, Kyusik Chung > wrote: >> >> Im using Ubuntu 8.04 on 64 bit hosts on rackspace cloud. >> >> Im in the middle of repeating some perf tests, but so far, I get as-good >> or slightly better read perf by using standard disk access mode vs mmap.= =A0So >> far consecutive tests are returning consistent numbers. >> >> Im not sure how to explain it...maybe its an ubuntu 8.04 issue with mmap= . >> =A0Back when I was using mmap, I was definitely seeing the kswapd0 proce= ss >> start using cpu as the box ran out of memory, and read performance >> significantly degraded. >> >> Next, Ill run some tests with mmap_index_only, and Ill test with heavy >> concurrent writes as well as reads. =A0Ill let everyone know what I find= . >> >> Kyusik Chung >> CEO, Discovereads.com >> kyusik@discovereads.com >> >> On May 4, 2010, at 12:27 PM, Jonathan Ellis wrote: >> >> > Are you using 32 bit hosts? =A0If not don't be scared of mmap using a >> > lot of address space, you have plenty. =A0It won't make you swap more >> > than using buffered i/o. >> > >> > On Tue, May 4, 2010 at 1:57 PM, Ran Tavory wrote: >> >> I canceled mmap and indeed memory usage is sane again. So far >> >> performance >> >> hasn't been great, but I'll wait and see. >> >> I'm also interested in a way to cap mmap so I can take advantage of i= t >> >> but >> >> not swap the host to death... >> >> >> >> On Tue, May 4, 2010 at 9:38 PM, Kyusik Chung >> >> wrote: >> >>> >> >>> This sounds just like the slowness I was asking about in another >> >>> thread - >> >>> after a lot of reads, the machine uses up all available memory on th= e >> >>> box >> >>> and then starts swapping. >> >>> My understanding was that mmap helps greatly with read and write per= f >> >>> (until the box starts swapping I guess)...is there any way to use mm= ap >> >>> and >> >>> cap how much memory it takes up? >> >>> What do people use in production? =A0mmap or no mmap? >> >>> Thanks! >> >>> Kyusik Chung >> >>> On May 4, 2010, at 10:11 AM, Schubert Zhang wrote: >> >>> >> >>> 1. When initially startup your nodes, please plan your InitialToken = of >> >>> each node evenly. >> >>> 2. standard >> >>> >> >>> On Tue, May 4, 2010 at 9:09 PM, Boris Shulman >> >>> wrote: >> >>>> >> >>>> I think that the extra (more than 4GB) memory usage comes from the >> >>>> mmaped io, that is why it happens only for reads. >> >>>> >> >>>> On Tue, May 4, 2010 at 2:02 PM, Jordan Pittier >> >>>> >> >>>> wrote: >> >>>>> I'm facing the same issue with swap. It only occurs when I perform >> >>>>> read >> >>>>> operations (write are very fast :)). So I can't help you with the >> >>>>> memory >> >>>>> probleme. >> >>>>> >> >>>>> But to balance the load evenly between nodes in cluster just >> >>>>> manually >> >>>>> fix >> >>>>> their token.(the "formula" is i * 2^127 / nb_nodes). >> >>>>> >> >>>>> Jordzn >> >>>>> >> >>>>> On Tue, May 4, 2010 at 8:20 AM, Ran Tavory wrot= e: >> >>>>>> >> >>>>>> I'm looking into performance issues on a 0.6.1 cluster. I see two >> >>>>>> symptoms: >> >>>>>> 1. Reads and writes are slow >> >>>>>> 2. One of the hosts is doing a lot of GC. >> >>>>>> 1 is slow in the sense that in normal state the cluster used to >> >>>>>> make >> >>>>>> around 3-5k read and writes per second (6-10k operations per >> >>>>>> second), >> >>>>>> but >> >>>>>> how it's in the order of 200-400 ops per second, sometimes even >> >>>>>> less. >> >>>>>> 2 looks like this: >> >>>>>> $ tail -f /outbrain/cassandra/log/system.log >> >>>>>> =A0INFO [GC inspection] 2010-05-04 00:42:18,636 GCInspector.java >> >>>>>> (line >> >>>>>> 110) >> >>>>>> GC for ParNew: 672 ms, 166482384 reclaimed leaving 2872087208 use= d; >> >>>>>> max is >> >>>>>> 4432068608 >> >>>>>> =A0INFO [GC inspection] 2010-05-04 00:42:28,638 GCInspector.java >> >>>>>> (line >> >>>>>> 110) >> >>>>>> GC for ParNew: 498 ms, 166493352 reclaimed leaving 2836049448 use= d; >> >>>>>> max is >> >>>>>> 4432068608 >> >>>>>> =A0INFO [GC inspection] 2010-05-04 00:42:38,640 GCInspector.java >> >>>>>> (line >> >>>>>> 110) >> >>>>>> GC for ParNew: 327 ms, 166091528 reclaimed leaving 2796888424 use= d; >> >>>>>> max is >> >>>>>> 4432068608 >> >>>>>> ... and it goes on and on for hours, no stopping... >> >>>>>> The cluster is made of 6 hosts, 3 in one DC and 3 in another. >> >>>>>> Each host has 8G RAM. >> >>>>>> -Xmx=3D4G >> >>>>>> For some reason, the load isn't distributed evenly b/w the hosts, >> >>>>>> although >> >>>>>> I'm not sure this is the cause for slowness >> >>>>>> $ nodetool -h localhost -p 9004 ring >> >>>>>> Address =A0 =A0 =A0 Status =A0 =A0 Load =A0 =A0 =A0 =A0 =A0Range >> >>>>>> =A0 =A0 =A0 =A0Ring >> >>>>>> >> >>>>>> 144413773383729447702215082383444206680 >> >>>>>> 192.168.252.99Up =A0 =A0 =A0 =A0 15.94 GB >> >>>>>> =A066002764663998929243644931915471302076 =A0 =A0 |<--| >> >>>>>> 192.168.254.57Up =A0 =A0 =A0 =A0 19.84 GB >> >>>>>> =A081288739225600737067856268063987022738 =A0 =A0 | =A0 ^ >> >>>>>> 192.168.254.58Up =A0 =A0 =A0 =A0 973.78 MB >> >>>>>> 86999744104066390588161689990810839743 =A0 =A0 v =A0 | >> >>>>>> 192.168.252.62Up =A0 =A0 =A0 =A0 5.18 GB >> >>>>>> 88308919879653155454332084719458267849 =A0 =A0 | =A0 ^ >> >>>>>> 192.168.254.59Up =A0 =A0 =A0 =A0 10.57 GB >> >>>>>> =A0142482163220375328195837946953175033937 =A0 =A0v =A0 | >> >>>>>> 192.168.252.61Up =A0 =A0 =A0 =A0 11.36 GB >> >>>>>> =A0144413773383729447702215082383444206680 =A0 =A0|-->| >> >>>>>> The slow host is 192.168.252.61 and it isn't the most loaded one. >> >>>>>> The host is waiting a lot on IO and the load average is usually 6= -7 >> >>>>>> $ w >> >>>>>> =A000:42:56 up 11 days, 13:22, =A01 user, =A0load average: 6.21, = 5.52, >> >>>>>> 3.93 >> >>>>>> $ vmstat 5 >> >>>>>> procs -----------memory---------- ---swap-- -----io---- --system-= - >> >>>>>> -----cpu------ >> >>>>>> =A0r =A0b =A0 swpd =A0 free =A0 buff =A0cache =A0 si =A0 so =A0 = =A0bi =A0 =A0bo =A0 in =A0 cs >> >>>>>> us >> >>>>>> sy id >> >>>>>> wa st >> >>>>>> =A00 =A08 2147844 =A045744 =A0 1816 4457384 =A0 =A06 =A0 =A05 =A0= =A066 =A0 =A032 =A0 =A05 =A0 =A02 >> >>>>>> =A01 >> >>>>>> =A01 >> >>>>>> 96 =A02 =A00 >> >>>>>> =A00 =A08 2147164 =A049020 =A0 1808 4451596 =A0385 =A0 =A00 =A023= 45 =A0 =A058 3372 9957 >> >>>>>> =A02 >> >>>>>> =A02 >> >>>>>> 78 18 =A00 >> >>>>>> =A00 =A03 2146432 =A045704 =A0 1812 4453956 =A0342 =A0 =A00 =A022= 74 =A0 108 3937 >> >>>>>> 10732 >> >>>>>> =A02 =A02 >> >>>>>> 78 19 =A00 >> >>>>>> =A00 =A01 2146252 =A044696 =A0 1804 4453436 =A0345 =A0164 =A01939= =A0 294 3647 7833 >> >>>>>> =A02 >> >>>>>> =A02 >> >>>>>> 78 18 =A00 >> >>>>>> =A00 =A01 2145960 =A046924 =A0 1744 4451260 =A0158 =A0 =A00 =A024= 23 =A0 122 4354 >> >>>>>> 14597 >> >>>>>> =A02 =A02 >> >>>>>> 77 18 =A00 >> >>>>>> =A07 =A01 2138344 =A044676 =A0 =A0952 4504148 1722 =A0403 =A01722= =A0 406 1388 =A0439 >> >>>>>> 87 >> >>>>>> =A00 >> >>>>>> 10 =A02 =A00 >> >>>>>> =A07 =A02 2137248 =A045652 =A0 =A0956 4499436 1384 =A0655 =A01384= =A0 658 1356 =A0392 >> >>>>>> 87 >> >>>>>> =A00 >> >>>>>> 10 =A03 =A00 >> >>>>>> =A07 =A01 2135976 =A046764 =A0 =A0956 4495020 1366 =A0718 =A01366= =A0 718 1395 =A0380 >> >>>>>> 87 >> >>>>>> =A00 >> >>>>>> =A09 =A04 =A00 >> >>>>>> =A00 =A08 2134484 =A046964 =A0 =A0956 4489420 1673 =A0555 =A01814= =A0 586 1601 >> >>>>>> 215590 >> >>>>>> 14 >> >>>>>> =A02 68 16 =A00 >> >>>>>> =A00 =A01 2135388 =A047444 =A0 =A0972 4488516 =A0785 =A0833 =A023= 90 =A0 995 3812 8305 >> >>>>>> =A02 >> >>>>>> =A02 >> >>>>>> 77 20 =A00 >> >>>>>> =A00 10 2135164 =A045928 =A0 =A0980 4488796 =A0788 =A0543 =A02275= =A0 626 36 >> >>>>>> So, the host is swapping like crazy... >> >>>>>> top shows that it's using a lot of memory. As noted before -Xmx= =3D4G >> >>>>>> and >> >>>>>> nothing else seems to be using a lot of memory on the host except >> >>>>>> for >> >>>>>> the >> >>>>>> cassandra process, however, of the 8G ram on the host, 92% is use= d >> >>>>>> by >> >>>>>> cassandra. How's that? >> >>>>>> Top shows there's 3.9g Shared and 7.2g Resident and 15.9g Virtual= . >> >>>>>> Why >> >>>>>> does it have 15g virtual? And why 7.2 RES? This can explain the >> >>>>>> slowness in >> >>>>>> swapping. >> >>>>>> $ top >> >>>>>> =A0 PID USER =A0 =A0 =A0PR =A0NI =A0VIRT =A0RES =A0SHR S %CPU %ME= M =A0 =A0TIME+ >> >>>>>> =A0COMMAND >> >>>>>> >> >>>>>> >> >>>>>> 20281 cassandr =A025 =A0 0 15.9g 7.2g 3.9g S 33.3 92.6 175:30.27 = java >> >>>>>> So, can the total memory be controlled? >> >>>>>> Or perhaps I'm looking in the wrong direction... >> >>>>>> I've looked at all the cassandra JMX counts and nothing seemed >> >>>>>> suspicious >> >>>>>> so far. By suspicious i mean a large number of pending tasks - >> >>>>>> there >> >>>>>> were >> >>>>>> always very small numbers in each pool. >> >>>>>> About read and write latencies, I'm not sure what the normal stat= e >> >>>>>> is, >> >>>>>> but >> >>>>>> here's an example of what I see on the problematic host: >> >>>>>> #mbean =3D org.apache.cassandra.service:type=3DStorageProxy: >> >>>>>> RecentReadLatencyMicros =3D 30105.888180684495; >> >>>>>> TotalReadLatencyMicros =3D 78543052801; >> >>>>>> TotalWriteLatencyMicros =3D 4213118609; >> >>>>>> RecentWriteLatencyMicros =3D 1444.4809201925639; >> >>>>>> ReadOperations =3D 4779553; >> >>>>>> RangeOperations =3D 0; >> >>>>>> TotalRangeLatencyMicros =3D 0; >> >>>>>> RecentRangeLatencyMicros =3D NaN; >> >>>>>> WriteOperations =3D 4740093; >> >>>>>> And the only pool that I do see some pending tasks is the >> >>>>>> ROW-READ-STAGE, >> >>>>>> but it doesn't look like much, usually around 6-8: >> >>>>>> #mbean =3D org.apache.cassandra.concurrent:type=3DROW-READ-STAGE: >> >>>>>> ActiveCount =3D 8; >> >>>>>> PendingTasks =3D 8; >> >>>>>> CompletedTasks =3D 5427955; >> >>>>>> Any help finding the solution is appreciated, thanks... >> >>>>>> Below are a few more JMXes I collected from the system that may b= e >> >>>>>> interesting. >> >>>>>> #mbean =3D java.lang:type=3DMemory: >> >>>>>> Verbose =3D false; >> >>>>>> HeapMemoryUsage =3D { >> >>>>>> =A0 committed =3D 3767279616; >> >>>>>> =A0 init =3D 134217728; >> >>>>>> =A0 max =3D 4293656576; >> >>>>>> =A0 used =3D 1237105080; >> >>>>>> =A0}; >> >>>>>> NonHeapMemoryUsage =3D { >> >>>>>> =A0 committed =3D 35061760; >> >>>>>> =A0 init =3D 24313856; >> >>>>>> =A0 max =3D 138412032; >> >>>>>> =A0 used =3D 23151320; >> >>>>>> =A0}; >> >>>>>> ObjectPendingFinalizationCount =3D 0; >> >>>>>> #mbean =3D java.lang:name=3DParNew,type=3DGarbageCollector: >> >>>>>> LastGcInfo =3D { >> >>>>>> =A0 GcThreadCount =3D 11; >> >>>>>> =A0 duration =3D 136; >> >>>>>> =A0 endTime =3D 42219272; >> >>>>>> =A0 id =3D 11719; >> >>>>>> =A0 memoryUsageAfterGc =3D { >> >>>>>> =A0 =A0 ( CMS Perm Gen ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D CMS Perm Gen; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 29229056; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 21757952; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 88080384; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 17648848; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( Code Cache ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D Code Cache; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 5832704; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 2555904; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 50331648; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 5563520; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( CMS Old Gen ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D CMS Old Gen; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 3594133504; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 112459776; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 4120510464; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 964565720; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( Par Eden Space ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D Par Eden Space; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 171835392; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 21495808; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 171835392; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 0; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( Par Survivor Space ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D Par Survivor Space; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 1310720; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 131072; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 1310720; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 0; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0}; >> >>>>>> =A0 memoryUsageBeforeGc =3D { >> >>>>>> =A0 =A0 ( CMS Perm Gen ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D CMS Perm Gen; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 29229056; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 21757952; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 88080384; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 17648848; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( Code Cache ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D Code Cache; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 5832704; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 2555904; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 50331648; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 5563520; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( CMS Old Gen ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D CMS Old Gen; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 3594133504; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 112459776; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 4120510464; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 959221872; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( Par Eden Space ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D Par Eden Space; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 171835392; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 21495808; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 171835392; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 171835392; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0 ( Par Survivor Space ) =3D { >> >>>>>> =A0 =A0 =A0 key =3D Par Survivor Space; >> >>>>>> =A0 =A0 =A0 value =3D { >> >>>>>> =A0 =A0 =A0 =A0 committed =3D 1310720; >> >>>>>> =A0 =A0 =A0 =A0 init =3D 131072; >> >>>>>> =A0 =A0 =A0 =A0 max =3D 1310720; >> >>>>>> =A0 =A0 =A0 =A0 used =3D 0; >> >>>>>> =A0 =A0 =A0 =A0}; >> >>>>>> =A0 =A0 =A0}; >> >>>>>> =A0 =A0}; >> >>>>>> =A0 startTime =3D 42219136; >> >>>>>> =A0}; >> >>>>>> CollectionCount =3D 11720; >> >>>>>> CollectionTime =3D 4561730; >> >>>>>> Name =3D ParNew; >> >>>>>> Valid =3D true; >> >>>>>> MemoryPoolNames =3D [ Par Eden Space, Par Survivor Space ]; >> >>>>>> #mbean =3D java.lang:type=3DOperatingSystem: >> >>>>>> MaxFileDescriptorCount =3D 63536; >> >>>>>> OpenFileDescriptorCount =3D 75; >> >>>>>> CommittedVirtualMemorySize =3D 17787711488; >> >>>>>> FreePhysicalMemorySize =3D 45522944; >> >>>>>> FreeSwapSpaceSize =3D 2123968512; >> >>>>>> ProcessCpuTime =3D 12251460000000; >> >>>>>> TotalPhysicalMemorySize =3D 8364417024; >> >>>>>> TotalSwapSpaceSize =3D 4294959104; >> >>>>>> Name =3D Linux; >> >>>>>> AvailableProcessors =3D 8; >> >>>>>> Arch =3D amd64; >> >>>>>> SystemLoadAverage =3D 4.36; >> >>>>>> Version =3D 2.6.18-164.15.1.el5; >> >>>>>> #mbean =3D java.lang:type=3DRuntime: >> >>>>>> Name =3D 20281@ob1061.nydc1.outbrain.com; >> >>>>>> >> >>>>>> ClassPath =3D >> >>>>>> >> >>>>>> >> >>>>>> /outbrain/cassandra/apache-cassandra-0.6.1/bin/../conf:/outbrain/= cassandra/apache-cassandra-0.6.1/bin/../build/classes:/outbrain/cassandra/a= pache-cassandra-0.6.1/bin/.. >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> /lib/antlr-3.1.3.jar:/outbrain/cassandra/apache-cassandra-0.6.1/b= in/../lib/apache-cassandra-0.6.1.jar:/outbrain/cassandra/apache-cassandra-0= .6.1/bin/../lib/avro-1.2.0-dev.jar:/outb >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> rain/cassandra/apache-cassandra-0.6.1/bin/../lib/clhm-production.= jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/commons-cli-1.1.j= ar:/outbrain/cassandra/apache-cassandra- >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> 0.6.1/bin/../lib/commons-codec-1.2.jar:/outbrain/cassandra/apache= -cassandra-0.6.1/bin/../lib/commons-collections-3.2.1.jar:/outbrain/cassand= ra/apache-cassandra-0.6.1/bin/../lib/com >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> mons-lang-2.4.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/= ../lib/google-collections-1.0.jar:/outbrain/cassandra/apache-cassandra-0.6.= 1/bin/../lib/hadoop-core-0.20.1.jar:/out >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> brain/cassandra/apache-cassandra-0.6.1/bin/../lib/high-scale-lib.= jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/ivy-2.1.0.jar:/ou= tbrain/cassandra/apache-cassandra-0.6.1/ >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> bin/../lib/jackson-core-asl-1.4.0.jar:/outbrain/cassandra/apache-= cassandra-0.6.1/bin/../lib/jackson-mapper-asl-1.4.0.jar:/outbrain/cassandra= /apache-cassandra-0.6.1/bin/../lib/jline >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> -0.9.94.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib= /json-simple-1.1.jar:/outbrain/cassandra/apache-cassandra-0.6.1/bin/../lib/= libthrift-r917130.jar:/outbrain/cassandr >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> a/apache-cassandra-0.6.1/bin/../lib/log4j-1.2.14.jar:/outbrain/ca= ssandra/apache-cassandra-0.6.1/bin/../lib/slf4j-api-1.5.8.jar:/outbrain/cas= sandra/apache-cassandra-0.6.1/bin/../lib >> >>>>>> /slf4j-log4j12-1.5.8.jar; >> >>>>>> >> >>>>>> BootClassPath =3D >> >>>>>> >> >>>>>> >> >>>>>> /usr/java/jdk1.6.0_17/jre/lib/alt-rt.jar:/usr/java/jdk1.6.0_17/jr= e/lib/resources.jar:/usr/java/jdk1.6.0_17/jre/lib/rt.jar:/usr/java/jdk1.6.0= _17/jre/lib/sunrsasign.j >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> ar:/usr/java/jdk1.6.0_17/jre/lib/jsse.jar:/usr/java/jdk1.6.0_17/j= re/lib/jce.jar:/usr/java/jdk1.6.0_17/jre/lib/charsets.jar:/usr/java/jdk1.6.= 0_17/jre/classes; >> >>>>>> >> >>>>>> LibraryPath =3D >> >>>>>> >> >>>>>> >> >>>>>> /usr/java/jdk1.6.0_17/jre/lib/amd64/server:/usr/java/jdk1.6.0_17/= jre/lib/amd64:/usr/java/jdk1.6.0_17/jre/../lib/amd64:/usr/java/packages/lib= /amd64:/lib:/usr/lib; >> >>>>>> >> >>>>>> VmName =3D Java HotSpot(TM) 64-Bit Server VM; >> >>>>>> >> >>>>>> VmVendor =3D Sun Microsystems Inc.; >> >>>>>> >> >>>>>> VmVersion =3D 14.3-b01; >> >>>>>> >> >>>>>> BootClassPathSupported =3D true; >> >>>>>> >> >>>>>> InputArguments =3D [ -ea, -Xms128M, -Xmx4G, >> >>>>>> -XX:TargetSurvivorRatio=3D90, >> >>>>>> -XX:+AggressiveOpts, -XX:+UseParNewGC, -XX:+UseConcMarkSweepGC, >> >>>>>> -XX:+CMSParallelRemarkEnabled, -XX:+HeapDumpOnOutOfMemoryError, >> >>>>>> -XX:SurvivorRatio=3D128, -XX:MaxTenuringThreshold=3D0, >> >>>>>> -Dcom.sun.management.jmxremote.port=3D9004, >> >>>>>> -Dcom.sun.management.jmxremote.ssl=3Dfalse, >> >>>>>> -Dcom.sun.management.jmxremote.authenticate=3Dfalse, >> >>>>>> >> >>>>>> >> >>>>>> -Dstorage-config=3D/outbrain/cassandra/apache-cassandra-0.6.1/bin= /../conf, >> >>>>>> -Dcassandra-pidfile=3D/var/run/cassandra.pid ]; >> >>>>>> >> >>>>>> ManagementSpecVersion =3D 1.2; >> >>>>>> >> >>>>>> SpecName =3D Java Virtual Machine Specification; >> >>>>>> >> >>>>>> SpecVendor =3D Sun Microsystems Inc.; >> >>>>>> >> >>>>>> SpecVersion =3D 1.0; >> >>>>>> >> >>>>>> StartTime =3D 1272911001415; >> >>>>>> ... >> >>>>> >> >>> >> >>> >> >> >> >> >> > >> > >> > >> > -- >> > Jonathan Ellis >> > Project Chair, Apache Cassandra >> > co-founder of Riptano, the source for professional Cassandra support >> > http://riptano.com >> > > --=20 Jonathan Ellis Project Chair, Apache Cassandra co-founder of Riptano, the source for professional Cassandra support http://riptano.com