Philip Thompson created CASSANDRA-9504: ------------------------------------------
Summary: 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 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)