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From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-6794) Optimise slab allocator to enable higher number of column families
Date Mon, 03 Mar 2014 15:15:24 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-6794?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jonathan Ellis updated CASSANDRA-6794:
--------------------------------------

      Priority: Minor  (was: Major)
    Issue Type: New Feature  (was: Improvement)

FTR, I still think "large numbers of CFs" is an antipattern that we don't want to encourage.
 Remember, the smaller the unit of a flush is, the closer we approach doing random i/o on
flush and compaction.

> Optimise slab allocator to enable higher number of column families
> ------------------------------------------------------------------
>
>                 Key: CASSANDRA-6794
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6794
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>            Reporter: Jeremy Hanna
>            Assignee: Benedict
>            Priority: Minor
>
> Currently the slab allocator allocates 1MB per column family.  This has been very beneficial
for gc efficiency.  However, it makes it more difficult to have large numbers of column families.
> It would be preferable to have a more intelligent way to allocate slabs so that there
is more flexibility between slab allocator and non-slab allocator behaviour.
> A simple first step is to ramp up size of slabs from small (say  8KB) when empty, to
1MB after a few slabs.



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