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https://issues.apache.org/jira/browse/CASSANDRA-3743?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-3743:
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Attachment: 3743-trunk-trim.txt
Slight update attached to use positions.trimToSize instead of leaving an
"orphan" arraylist around. As mentioned above, the size difference is
negligible.
Question: is the getKeySamples transform still necessary, or can we just cast
the keys collection?
Or could we just make it a List of DK in the first place instead of RP?
> Lower memory consumption used by index sampling
> -----------------------------------------------
>
> Key: CASSANDRA-3743
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3743
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 1.0.0
> Reporter: Radim Kolar
> Assignee: Radim Kolar
> Labels: optimization
> Fix For: 1.1
>
> Attachments: 3743-trunk-trim.txt, 3743-trunk.txt,
> cassandra-3743-codestyle.txt
>
>
> currently j.o.a.c.io.sstable.indexsummary is implemented as ArrayList of
> KeyPosition (RowPosition key, long offset)i propose to change it to:
> RowPosition keys[]
> long offsets[]
> and use standard binary search on it. This will lower number of java objects
> used per entry from 2 (KeyPosition + RowPosition) to 1 (RowPosition).
> For building these arrays convenient ArrayList class can be used and then
> call to .toArray() on it.
> This is very important because index sampling uses a lot of memory on nodes
> with billions rows
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