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https://issues.apache.org/jira/browse/CASSANDRA-4694?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13723129#comment-13723129
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Robert Coli commented on CASSANDRA-4694:
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populate_io_cache_on_flush seems misnamed for something which affects behavior
both at flush time (_on_flush) and at compaction time (_on_compaction?).
With the current name, there is a risk of users becoming confused and thinking
that the process of writing out a SSTable is a "flush", when in Cassandra 99.9%
of the time a "flush" is in fact the process of turning a memtable into a
SSTable.
http://pastebin.com/GJMVZP9v
Shows that the overwhelming majority of uses of "flush" in user visible code
paths refer only to the concept of "flush"ing a memtable.
I understand that the function in question is called "flushInternal," but
submit that we are inviting confusion by conflating the specific "flush"ing of
a memtable with generic "flush"ing data to disk. :)
"populate_io_cache_on_create" maybe? with "create" referring to the new file
being "create"d on disk? I am willing to submit a patch if needed..
> populate_io_cache_on_flush option should be configurable for each column
> family independently
> ---------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-4694
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4694
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Alexey Zotov
> Assignee: Alexey Zotov
> Priority: Minor
> Labels: cli, core, documentation
> Fix For: 1.2.2
>
> Attachments: cassandra-1.1.2-4694-populate_io_cache_v3.txt,
> cassandra-1.1-4694-populate_io_cache.txt,
> cassandra-1.2-4694-populate_io_cache.txt,
> cassandra-1.2-4694-populate_io_cache_v2.txt,
> cassandra-1.2-populate_io_cache_v4.txt
>
>
> I suggest to configure populate_io_cache_on_flush option for each column
> family. It should be configurable from cassandra-cli and should be stored in
> System keyspace.
> That could be useful if you have a few column families inside single keyspace
> and you need to fit in memory only one of them.
> Patch has been attached. I've been testing it on pseudo-cluster using ccm. So
> I don't have fully confidence about lack of bugs. Please carefully review
> that code.
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