hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Lars Hofhansl (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-9316) Use JoinedHeap between MUST_PASS_ALL filters to better leverage essential column family feature
Date Fri, 23 Aug 2013 01:05:52 GMT

    [ https://issues.apache.org/jira/browse/HBASE-9316?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13748175#comment-13748175
] 

Lars Hofhansl commented on HBASE-9316:
--------------------------------------

I like this idea for performance reasons. But I do not understand how it would help to distinguish
a null column from an absent column.
                
> Use JoinedHeap between MUST_PASS_ALL filters to better leverage essential column family
feature 
> ------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-9316
>                 URL: https://issues.apache.org/jira/browse/HBASE-9316
>             Project: HBase
>          Issue Type: Bug
>            Reporter: James Taylor
>
> Currently, all column families in a MUST_PASS_ALL filter list are loaded in advance of
filtering. Instead, only the essential column family from the first filter should be loaded
and then its heap joined with subsequent essential column family from the next filter in the
list (probably up to some reasonable/configurable limit).
> One particular Phoenix use case for this is when a SQL query is trying to detect the
absence of a KeyValue (though a <column> IS NULL clause). Our workaround for a Phoenix
TABLE is to insert a known, empty key value with every row, or for a Phoenix VIEW (mapping
to an existing HBase table) to project everything. With this feature, we could instead use
a filter per column family and prevent the loading of the corresponding Store in many cases.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message