[
https://issues.apache.org/jira/browse/LUCENE-743?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12532867
]
Michael McCandless commented on LUCENE-743:
-------------------------------------------
> > Too bad so much needs to be cloned in the case that
> > closeOldReader==false... maybe someday in the future we can have
> > read-only readers.
>
> Yeah, the cloning part was kind of tedious. Read-only readers would
> indeed make our life much easier here. I'm wondering how many people
> are using the IndexReader to alter the norms anyway?
I think the closeOldReader=false case is actually quite important.
Because in production, I think you'd have to use that, so that your
old reader stays alive and is used to service incoming queries, up
until the point where the re-opened reader is "fully warmed".
Since fully warming could take a long time (minutes?) you need that
old reader to stay open.
Can we take a copy-on-write approach? EG, this is how OS's handle the
virtual memory pages when forking a process. This would mean whenever
a clone has been made of a SegmentReader, they cross-reference one
another. Then whenever either needs to alter deleted docs, one of them
makes a copy then. Likewise for the norms.
This would mean that "read-only" uses of the cloned reader never
pay the cost of copying the deleted docs bit vector nor norms.
> IndexReader.reopen()
> --------------------
>
> Key: LUCENE-743
> URL: https://issues.apache.org/jira/browse/LUCENE-743
> Project: Lucene - Java
> Issue Type: Improvement
> Components: Index
> Reporter: Otis Gospodnetic
> Assignee: Michael Busch
> Priority: Minor
> Fix For: 2.3
>
> Attachments: IndexReaderUtils.java, lucene-743-take2.patch,
> lucene-743.patch, lucene-743.patch, lucene-743.patch, MyMultiReader.java,
> MySegmentReader.java
>
>
> This is Robert Engels' implementation of IndexReader.reopen() functionality,
> as a set of 3 new classes (this was easier for him to implement, but should
> probably be folded into the core, if this looks good).
--
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: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
