Andrey Gura created IGNITE-7820: ----------------------------------- Summary: Investigate and fix perfromance drop of WAL for default mode Key: IGNITE-7820 URL: https://issues.apache.org/jira/browse/IGNITE-7820 Project: Ignite Issue Type: Bug Affects Versions: 2.4 Reporter: Andrey Gura Fix For: 2.5
WAL performance drop was introduced by https://issues.apache.org/jira/browse/IGNITE-6339 fix. In order to provide better performance for {{DEFAULT}} WAL mode {{FsyncModeFileWriteAheadLogManager}} implementation was added as result of fix issue https://issues.apache.org/jira/browse/IGNITE-7594. What we know about this performance drop: * It affects {{IgnitePutAllBenchmark}} and {{IgnitePutAllTxBenchmark}} and measurements show 10-15% drop and ~50% drop accordingly. * It is reproducible not for all hardware configuration. That is for some configuration we see only performance improvements instead of drop. * It is reproducible for [Many clients --> One server] topology. * If {{IGNITE_WAL_MMAP == false}} then we have better performance. * If {{fsyncDelay == 0}} then we have better performance. What were tried during initial investigation: * Replacing of {{LockSupport.park/unpark}} to spin leads to improvement about 2%. * Using {{FileWriteHandle.fsync(null)}} (unconditional flush) instead of {{FileWriteHandle.fsync(position)}} (conditional flush) doesn't affect benchmarks. What should we do: Investigate the problem and provide fix or recommendation for system tuning. -- This message was sent by Atlassian JIRA (v7.6.3#76005)