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https://issues.apache.org/jira/browse/OAK-4412?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15395182#comment-15395182
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Chetan Mehrotra commented on OAK-4412:
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While implementing this we can also make use of Near Real Time search feature
of Lucene [1] [2]. The observer can keep the writer open and upon any writes
(and with some minimum delay) the reader can be obtained from that writer. This
would ensure that we can reduce the overhead of open->close->open cycle if
content is changing frequently
[1]
http://blog.mikemccandless.com/2011/06/lucenes-near-real-time-search-is-fast.html
[2] https://wiki.apache.org/lucene-java/NearRealtimeSearch
> Lucene hybrid index
> -------------------
>
> Key: OAK-4412
> URL: https://issues.apache.org/jira/browse/OAK-4412
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: lucene
> Reporter: Tomek Rękawek
> Assignee: Tomek Rękawek
> Fix For: 1.6
>
> Attachments: OAK-4412.patch
>
>
> When running Oak in a cluster, each write operation is expensive. After
> performing some stress-tests with a geo-distributed Mongo cluster, we've
> found out that updating property indexes is a large part of the overall
> traffic.
> The asynchronous index would be an answer here (as the index update won't be
> made in the client request thread), but the AEM requires the updates to be
> visible immediately in order to work properly.
> The idea here is to enhance the existing asynchronous Lucene index with a
> synchronous, locally-stored counterpart that will persist only the data since
> the last Lucene background reindexing job.
> The new index can be stored in memory or (if necessary) in MMAPed local
> files. Once the "main" Lucene index is being updated, the local index will be
> purged.
> Queries will use an union of results from the {{lucene}} and
> {{lucene-memory}} indexes.
> The {{lucene-memory}} index, as a local stored entity, will be updated using
> an observer, so it'll get both local and remote changes.
> The original idea has been suggested by [~chetanm] in the discussion for the
> OAK-4233.
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