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Benedict commented on CASSANDRA-8833: ------------------------------------- bq. there may be unintended side-effects to some of those changes I have no doubt, which is partially why I consider this premature. We had a period of problems (not isolated to this, I want to reiterate), and we've had a very recent attempt to put them to bed. But not let that settle down to see how successful it has been. I'm expecting a few more minor hiccups. If we see some more major ones, especially regressions, that's a different matter. bq. Thus far we've avoided platform-specific code-paths as much as possible, but that seems a simple enough solution that it would be worth looking into. I'd actually be totally cool with (and maybe even prefer) making this a universal behaviour. That way we don't have multiple mappings of the same file, and we still retain most of the upside, with no behavioural split. > Stop opening compaction results early > ------------------------------------- > > Key: CASSANDRA-8833 > URL: https://issues.apache.org/jira/browse/CASSANDRA-8833 > Project: Cassandra > Issue Type: Improvement > Reporter: Marcus Eriksson > Fix For: 2.1.4 > > > We should simplify the code base by not doing early opening of compaction > results. It makes it very hard to reason about sstable life cycles since they > can be in many different states, "opened early", "starts moved", "shadowed", > "final", instead of as before, basically just one (tmp files are not really > 'live' yet so I don't count those). The ref counting of shared resources > between sstables in these different states is also hard to reason about. This > has caused quite a few issues since we released 2.1 > I think it all boils down to a performance vs code complexity issue, is > opening compaction results early really 'worth it' wrt the performance gain? > The results in CASSANDRA-6916 sure look like the benefits are big enough, but > the difference should not be as big for people on SSDs (which most people who > care about latencies are) > WDYT [~benedict] [~jbellis] [~iamaleksey] [~JoshuaMcKenzie]? -- This message was sent by Atlassian JIRA (v6.3.4#6332)