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Jason Brown commented on CASSANDRA-6890: ---------------------------------------- Hmm, are we sure we really want to do this before CASSANDRA-5863 is proven (or even implemented)? The v1 patch is simple enough, but we are taking a known performance hit against an unknown future payoff. How much simpler would removing the mmap path make implementing CASSANDRA-5863? I can't imagine it'd make that much of a difference? Furthermore, if anyone is truly interested, I'll be talking about direct i/o (O_DIRECT) at the 2014 NGCC. > Standardize on a single read path > --------------------------------- > > Key: CASSANDRA-6890 > URL: https://issues.apache.org/jira/browse/CASSANDRA-6890 > Project: Cassandra > Issue Type: Improvement > Components: Core > Reporter: Joshua McKenzie > Assignee: Joshua McKenzie > Labels: performance > Fix For: 3.0 > > Attachments: 6890_v1.txt, mmap_gc.jpg, mmap_jstat.txt, mmap_perf.txt, > nommap_gc.jpg, nommap_jstat.txt > > > Since we actively unmap unreferenced SSTR's and also copy data out of those > readers on the read path, the current memory mapped i/o is a lot of > complexity for very little payoff. Clean out the mmapp'ed i/o on the read > path. -- This message was sent by Atlassian JIRA (v6.2#6252)