[
https://issues.apache.org/jira/browse/LUCENE-8198?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16394669#comment-16394669
]
Simon Willnauer commented on LUCENE-8198:
-----------------------------------------
> There are some advantages of doing it this way far as performance goes I
>think. For example, take the extreme case where a user never "hard"-deletes at
>all. They'd still always get bulk merge optimizations from the stored fields
>writer, etc.
that is a good one. Yet, I think the case where we never had hard deletes are
unlikely true for this usecase. It only applies if there are deletes at all at
least that is what I was focusing on.
> Well the overhead should be... 1 bit per document unless something is wrong?
>So a user would add something like a "soft live" field and then just update it
>to a 0. I think its easy to filter on such fields in searches already.
there is additonal memory overhead when indexing which can be not massive for
deletes / DV updates but still. I also try to understand how you can use
updateable docvalues to do that in an atomic fashion. it must be somehow part
of updateDocument which I wonder if it's the right way to go.
> Add ability to persist deletes across merges
> --------------------------------------------
>
> Key: LUCENE-8198
> URL: https://issues.apache.org/jira/browse/LUCENE-8198
> Project: Lucene - Core
> Issue Type: Improvement
> Affects Versions: 7.3, master (8.0)
> Reporter: Simon Willnauer
> Assignee: Simon Willnauer
> Priority: Major
> Attachments: LUCENE-8198.patch
>
>
> This allows conditionally persist deletes on a per document basis to prevent
> them from being merged away. This expert feature is useful to maintain
> history of documents in the index where otherwise a duplicate storage
> mechanism would be needed. For instance features like CouchDBs changes API
> can be build on top of persistent deletes. While using persistent deletes has
> a considerably small overhead at merge time or when deletes applied to fully
> deleted segments, there is no impact if persistent deletes are unused.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
