[ 
https://issues.apache.org/jira/browse/LUCENE-2810?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12970838#action_12970838
 ] 

Simon Willnauer commented on LUCENE-2810:
-----------------------------------------

bq. I think Grant was looking for something that could compress across fields 
of different documents (i.e. where every document represents a log record).

right, I understand the reason for that issue and I think it makes sense to 
implement something like that on a codec basis as it has a whole bunch or 
limitations I guess. For instance how do you deal with partial field loading? I 
mean you have to decompress everything really unless you have a compression 
scheme that allows to do something like a block cipher though. Not sure if 
something like that is around so input is appreciated. Still unless we don' t 
have codec support for stored fields I think we should not do it though.

simon

> Stored Fields Compression
> -------------------------
>
>                 Key: LUCENE-2810
>                 URL: https://issues.apache.org/jira/browse/LUCENE-2810
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Store
>            Reporter: Grant Ingersoll
>            Assignee: Grant Ingersoll
>
> In some cases (logs, HTML pages w/ boilerplate, etc.), the stored fields for 
> documents contain a lot of redundant information and end up wasting a lot of 
> space across a large collection of documents.  For instance, simply 
> compressing a typical log file often results in > 75% compression rates.  We 
> should explore mechanisms for applying compression across all the documents 
> for a field (or fields) while still maintaining relatively fast lookup (that 
> being said, in most logging applications, fast retrieval of a given event is 
> not always critical.)  For instance, perhaps it is possible to have a part of 
> storage that contains the set of unique values for all the fields and the 
> document field value simply contains a reference (could be as small as a few 
> bits depending on the number of uniq. items) to that value instead of having 
> a full copy.  Extending this, perhaps we can leverage some existing 
> compression capabilities in Java to provide this as well.  
> It may make sense to implement this as a Directory, but it might also make 
> sense as a Codec, if and when we have support for changing storage Codecs.

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


---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org
For additional commands, e-mail: dev-h...@lucene.apache.org

Reply via email to