Todd Lipcon has submitted this change and it was merged. Change subject: tablet: change default bloom filter FP rate to 0.01% ......................................................................
tablet: change default bloom filter FP rate to 0.01% The old default, 1%, was high enough that in a uniform random write workload, we ended up needing to read in most of the key blocks even with bloom filters enabled. On a 5 node cluster, after inserting a few billion rows, the write throughput dropped dramatically as every batch of writes was seeking and reading keys off disk. In testing on the same cluster, changing the FP rate to 0.01% improved the throughput dramatically (>2x) by reducing the random reads coming off disk. The cost is a 2x increase in bloom filter size (20 bits per key vs 10) but 20 bits is still a small percentage compared to typical row key sizes in target applications. Of course if an application has no random write characteristics and really cares about disk space, this can always be flipped back. Screenshots of the inserts/second graph (1hr rolling average) for these tests are at: https://gist.github.com/toddlipcon/1ab9b36b7fbae10b635d3a905e1fe55a Change-Id: I99bdd6298349a5be5f1fc3a666fe04305699e293 Reviewed-on: http://gerrit.cloudera.org:8080/3517 Tested-by: Kudu Jenkins Reviewed-by: Jean-Daniel Cryans <jdcry...@apache.org> Reviewed-by: David Ribeiro Alves <dral...@apache.org> --- M docs/release_notes.adoc M src/kudu/tablet/tablet.cc 2 files changed, 10 insertions(+), 1 deletion(-) Approvals: David Ribeiro Alves: Looks good to me, approved Jean-Daniel Cryans: Looks good to me, approved Kudu Jenkins: Verified -- To view, visit http://gerrit.cloudera.org:8080/3517 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: merged Gerrit-Change-Id: I99bdd6298349a5be5f1fc3a666fe04305699e293 Gerrit-PatchSet: 3 Gerrit-Project: kudu Gerrit-Branch: master Gerrit-Owner: Todd Lipcon <t...@apache.org> Gerrit-Reviewer: David Ribeiro Alves <dral...@apache.org> Gerrit-Reviewer: Jean-Daniel Cryans <jdcry...@apache.org> Gerrit-Reviewer: Kudu Jenkins Gerrit-Reviewer: Todd Lipcon <t...@apache.org>
