[jira] [Updated] (CASSANDRA-1956) Convert row cache to row+filter cache

["Vijay (Updated) (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-1956?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vijay updated CASSANDRA-1956:
-----------------------------

    Attachment: 0001-1956-cache-updates-v0.patch
                0002-1956-updates-to-thrift-and-avro-v0.patch

an alternative approach: 

This is still v0/proto-type once you guys agree on this i will make a fresh version.

Ledger is mainly a look up map to invalidate the filters when there is new changes.

Things to do:
1) Make ledger an object and attach it to the cache instead of extending ASC
2) More fine grain locks on the ledger
                
> Convert row cache to row+filter cache
> -------------------------------------
>
>                 Key: CASSANDRA-1956
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1956
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Stu Hood
>            Assignee: Daniel Doubleday
>            Priority: Minor
>             Fix For: 1.1
>
>         Attachments: 0001-1956-cache-updates-v0.patch, 0001-row-cache-filter.patch, 0002-1956-updates-to-thrift-and-avro-v0.patch
>
>
> Changing the row cache to a row+filter cache would make it much more useful. We currently have to warn against using the row cache with wide rows, where the read pattern is typically a peek at the head, but this usecase would be perfect supported by a cache that stored only columns matching the filter.
> Possible implementations:
> * (copout) Cache a single filter per row, and leave the cache key as is
> * Cache a list of filters per row, leaving the cache key as is: this is likely to have some gotchas for weird usage patterns, and it requires the list overheard
> * Change the cache key to "rowkey+filterid": basically ideal, but you need a secondary index to lookup cache entries by rowkey so that you can keep them in sync with the memtable
> * others?

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