[jira] Commented: (CASSANDRA-1207) Don't write BloomFilters for skinny rows

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

    [ https://issues.apache.org/jira/browse/CASSANDRA-1207?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12880397#action_12880397 ] 

Jonathan Ellis commented on CASSANDRA-1207:
-------------------------------------------

i'm skeptical that reading an index block's worth of columns is cheaper than reading a bloom filter, even for skinny rows

(the main reason we have bloom filters is because in update-heavy workloads we will have lots of row versions, most of which only have a few columns, so when we are requesting specific column names we want to reject rows that don't have that column at all as early as we can)

> Don't write BloomFilters for skinny rows
> ----------------------------------------
>
>                 Key: CASSANDRA-1207
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1207
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Stu Hood
>            Priority: Critical
>             Fix For: 0.7
>
>         Attachments: 0001-Return-alwaysMatchingBloomFilter-for-0-length-filter.patch, 0002-Conditionally-write-the-row-bloom-filter.patch
>
>
> All rows currently contain a serialized BloomFilter, regardless of size. For smaller rows, it is much more efficient in space and CPU time to not write a BloomFilter, and to eagerly perform lookups against the existing columns.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.