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Philip Thompson commented on CASSANDRA-9504: -------------------------------------------- Trace from 2.0: http://aep.appspot.com/display/DB8uqK7rk9guAovo3dwpCJdanmc/ Trace from 2.1-head: http://aep.appspot.com/display/74MMGT5WOND_7C7Enn3zh_ZuCxY/ > Odd performance numbers comparing 2.0.15 and 2.1+ > ------------------------------------------------- > > Key: CASSANDRA-9504 > URL: https://issues.apache.org/jira/browse/CASSANDRA-9504 > Project: Cassandra > Issue Type: Bug > Reporter: Philip Thompson > Attachments: jstack.tar.gz > > > I've been doing some basic performance testing of batch commitlog on 2.0.15, > 2.1-head, and 2.2.-head. I have been seeing very odd results where 2.0.15 > performance is incredibly high, suspiciously so, when compared to 2.1 or 2.2. > Example graph: > http://cstar.datastax.com/graph?stats=2ea11748-0562-11e5-9045-42010af0688f&metric=op_rate&operation=1_write&smoothing=1&show_aggregates=true&xmin=0&xmax=1570.36&ymin=0&ymax=127509.8 > I'm using the following yaml options: > {code} > commitlog_sync: batch > commitlog_sync_batch_window_in_ms: 50 > commitlog_sync_period_in_ms: null > concurrent_writes: 64 > {code} > I am able to reproduce this on two separate clusters, physical hardware, with > SSDs. I have not been able to reproduce this on gce, or a physical cluster I > have access to with HDD. I can reproduce this consistently, with different > stress options, and with higher data load on the nodes. I can also reproduce > this myself on these machines, without using the C* perf tool to set up the > cluster and perform the operations. > When running 2.0.15 batch commitlog vs periodic, I do see a difference as > expected: > http://cstar.datastax.com/graph?stats=4ae77aac-056f-11e5-8344-42010af0688f&metric=op_rate&operation=1_write&smoothing=1&show_aggregates=true&xmin=0&xmax=68.09&ymin=0&ymax=166966.8 > I am using the newest stress code on trunk. What should I be looking for to > explain the anomalous performance here? -- This message was sent by Atlassian JIRA (v6.3.4#6332)