[jira] Commented: (CASSANDRA-1302) Allow Row Iterator to use the RowCache

["Jonathan Ellis (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-1302?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12890494#action_12890494 ] 

Jonathan Ellis commented on CASSANDRA-1302:
-------------------------------------------

(a) we don't want to pollute the row cache w/ data from range queries, since you can completely displace your hot rows w/ a single RQ of rows that will never be used again.

(b) the reason RIF is going through so much drama there is we are going through a lot of effort to be able to re-use the readers and filters from one row on the next one.  once you're scanning through non-hot data (e.g. most hadoop jobs) using normal getCF is going to be much slower.

(c) it should be okay to check the row cache as a fast-path though.  maybe even populate the row cache _if_ the row cache is not full to capacity.

> Allow Row Iterator to use the RowCache
> --------------------------------------
>
>                 Key: CASSANDRA-1302
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1302
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: T Jake Luciani
>         Attachments: row-iterator-cache-patch.txt
>
>
> Range slices are very slow. 
> I've discovered this is caused by the RowIterator ignoring the row cache.
> I've altered the code to use the row cache and now see a factor of 30 performance boost.

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