cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jonathan Ellis (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-1956) Convert row cache to row+filter cache
Date Thu, 05 Jan 2012 02:30:39 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-1956?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13180133#comment-13180133
] 

Jonathan Ellis commented on CASSANDRA-1956:
-------------------------------------------

bq. I thought that there are some common cases like tail and head caching or exclusion of
columns that could be implemented.

Right.  That's what we want to get out of this -- well, the tail/head part, since query cache
can only cache what you do ask for, but it can't exclude what you don't.  (Although if you
never query the excluded column... close enough, right?)

bq. So to prevent a rude awakening for some users it might be cool to provide some means (config
or whatever) that works similar as the current version.

Good point.  Damn it. :)

                
> 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: Vijay
>            Priority: Minor
>             Fix For: 1.2
>
>         Attachments: 0001-1956-cache-updates-v0.patch, 0001-re-factor-row-cache.patch,
0001-row-cache-filter.patch, 0002-1956-updates-to-thrift-and-avro-v0.patch, 0002-add-query-cache.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?

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message