hi , the same partition key on a single node are atomic and isolated? sorry,i don't read the source code ,but i think the cassandra is single thread on the same keyspace ,not he partition key, and the same keyspace is atomic and isolated . because, when the client insert data into table a and b ,the throught on table ' a is drop , and a + b 'sum is the 20000/s .
郝加来 From: Graham Sanderson Date: 2015-11-06 11:06 To: user@cassandra.apache.org Subject: Re: why cassanra max is 20000/s on a node ? Agreed too. It also matters what you are inserting… if you are inserting to the same (or small set of) partition key(s) you will be limited because writes to the same partition key on a single node are atomic and isolated. On Nov 5, 2015, at 8:49 PM, Venkatesh Arivazhagan <venkey.a...@gmail.com> wrote: I agree with Tyler! Have you tries increasing the the client threads from 5 to a higher number? On Nov 5, 2015 6:46 PM, "郝加来" <ha...@neusoft.com> wrote: right , but wo want a node 's throught is above million , so if the system hava fifty table , a single table can achive 20000/s . 郝加来 From: Eric Stevens Date: 2015-11-05 23:56 To: user@cassandra.apache.org Subject: Re: why cassanra max is 20000/s on a node ? > 512G memory , 128core cpu This seems dramatically oversized for a Cassandra node. You'd do much better to have a much larger cluster of much smaller nodes. On Thu, Nov 5, 2015 at 8:25 AM Jack Krupansky <jack.krupan...@gmail.com> wrote: I don't know what current numbers are, but last year the idea of getting 1 million writes per second on a 96 node cluster was considered a reasonable achievement. That would be roughly 10,000 writes per second per node and you are getting twice that. See: http://www.datastax.com/1-million-writes Or this Google test which hit 1 million writes per second with 330 nodes, which would be roughly 3,000 writes per second per node: http://googlecloudplatform.blogspot.com/2014/03/cassandra-hits-one-million-writes-per-second-on-google-compute-engine.html So, is your question why your throughput is so good or are you disappointed that it wasn't better? Cassandra is designed for clusters with lots of nodes, so if you want to get an accurate measure of per-node performance you need to test with a reasonable number of nodes and then divide aggregate performance by the number of nodes, not test a single node alone. In short, testing a single node in isolation is not a recommended approach to testing Cassandra performance. -- Jack Krupansky On Thu, Nov 5, 2015 at 9:05 AM, 郝加来 <ha...@neusoft.com> wrote: hi veryone i setup cassandra 2.2.3 on a node , the machine 's environment is openjdk-1.8.0 , 512G memory , 128core cpu , 3T ssd . the token num is 256 on a node , the program use datastax driver 2.1.8 and use 5 thread to insert data to cassandra on the same machine , the data 's capcity is 6G and 1157000 line . why is the throughput 20000/s on the node ? # Per-thread stack size. JVM_OPTS="$JVM_OPTS -Xss512k" # Larger interned string table, for gossip's benefit (CASSANDRA-6410) JVM_OPTS="$JVM_OPTS -XX:StringTableSize=1000003" # GC tuning options JVM_OPTS="$JVM_OPTS -XX:+CMSIncrementalMode" JVM_OPTS="$JVM_OPTS -XX:+DisableExplicitGC" JVM_OPTS="$JVM_OPTS -XX:+CMSConcurrentMTEnabled" JVM_OPTS="$JVM_OPTS -XX:+UseParNewGC" JVM_OPTS="$JVM_OPTS -XX:+UseConcMarkSweepGC" JVM_OPTS="$JVM_OPTS -XX:+CMSParallelRemarkEnabled" JVM_OPTS="$JVM_OPTS -XX:SurvivorRatio=4" JVM_OPTS="$JVM_OPTS -XX:MaxTenuringThreshold=2" JVM_OPTS="$JVM_OPTS -XX:CMSInitiatingOccupancyFraction=75" JVM_OPTS="$JVM_OPTS -XX:+UseCMSInitiatingOccupancyOnly" JVM_OPTS="$JVM_OPTS -XX:+UseTLAB" JVM_OPTS="$JVM_OPTS -XX:CompileCommandFile=$CASSANDRA_CONF/hotspot_compiler" JVM_OPTS="$JVM_OPTS -XX:CMSWaitDuration=60000" memtable_heap_space_in_mb: 1024 memtable_offheap_space_in_mb: 10240 memtable_cleanup_threshold: 0.55 memtable_allocation_type: heap_buffers 以上 谢谢 郝加来 金融华东事业部 <东软20周年邮件签名logo(1(11-06-10-44-31).jpg> 东软集团股份有限公司 上海市闵行区紫月路1000号东软软件园 Postcode：200241 Tel：(86 21) 33578591 Fax：(86 21) 23025565-111 Mobile：13764970711 Email：ha...@neusoft.com Http://www.neusoft.com --------------------------------------------------------------------------------------------------- Confidentiality Notice: The information contained in this e-mail and any accompanying attachment(s) is intended only for the use of the intended recipient and may be confidential and/or privileged of Neusoft Corporation, its subsidiaries and/or its affiliates. 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