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https://issues.apache.org/jira/browse/CASSANDRA-10995?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15117606#comment-15117606
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Jim Witschey commented on CASSANDRA-10995:
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[~benedict] Thanks for your comments.
bq. But only if the population is very small, since you would need for the data
to occur multiple times on a single page.
I've been assuming that compression happened per-sstable -- am I wrong about
that? Is this behavior documented somewhere?
bq. Realistically a dictionary generator should be added, which is not very
hard, and was on my todo list for a long time. That or a weighted random byte
generator, that is more likely to produce certain bytes (or byte sequences)
than others, which would avoid the necessity of a dictionary while providing
the same benefit.
Good idea. [~tjake]: If it's as simple as Benedict indicates, how soon could
you put together a basic dictionary generator? If a usable version were on a
branch somewhere in the next few days, it'd be useful for this benchmark. As
discussed, though, I can work around it if you aren't able.
> Consider disabling sstable compression by default in 3.x
> --------------------------------------------------------
>
> Key: CASSANDRA-10995
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10995
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Aleksey Yeschenko
> Assignee: Jim Witschey
>
> With the new sstable format introduced in CASSANDRA-8099, it's very likely
> that enabled sstable compression is no longer the right default option.
> [~slebresne]'s [blog post|http://www.datastax.com/2015/12/storage-engine-30]
> on the new storage engine has some comparison numbers for 2.2/3.0, with and
> without compression that show that in many cases compression no longer has a
> significant effect on sstable sizes - all while sill consuming extra
> resources for both writes (compression) and reads (decompression).
> We should run a comprehensive set of benchmarks to determine whether or not
> compression should be switched to 'off' now in 3.x.
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