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https://issues.apache.org/jira/browse/CASSANDRA-10378?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14903200#comment-14903200
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Benedict commented on CASSANDRA-10378:
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I would be in favour of that, as we could at the same time encode the _prior_
row's size as well, and this would permit us scanning both forwards and
backwards.
> Make skipping more efficient
> ----------------------------
>
> Key: CASSANDRA-10378
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10378
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Benedict
> Assignee: Benedict
> Fix For: 3.x
>
>
> Following on from the impact of CASSANDRA-10322, we can improve the
> efficiency of our calls to skipping methods. CASSANDRA-10326 is showing our
> performance to be in-and-around the same ballpark except for seeks into the
> middle of a large partition, which suggests (possibly) that the higher
> density of data we're storing may simply be resulting in a more significant
> CPU burden as we have more data to skip over (and since CASSANDRA-10322
> improves performance here really dramatically, further improvements are
> likely to be of similar benefit).
> I propose doing our best to flatten the skipping of macro data items into as
> few skip invocations as necessary. One way of doing this would be to
> introduce a special {{skipUnsignedVInts(int)}} method, that can efficiently
> skip a number of unsigned vints. Almost the entire body of a cell and row
> consist of vints now, each data component with their own special {{skipX}}
> method that invokes {{readUnsignedVint}}. This would permit more efficient
> despatch.
> We could also potentially avoid the construction of a new {{Columns}}
> instance for each row skip, since all we need is an iterator over the
> columns, and share the temporary space used for storing them, which should
> further reduce the GC burden for skipping many rows.
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