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Posted to oak-dev@jackrabbit.apache.org by Julian Sedding <js...@apache.org> on 2016/11/21 14:33:02 UTC

Is Lucene CopyOnRead/CopyOnWrite beneficial with SegmentNodeStore?

Hi all

Do we have experience or measurements to suggest that using Lucene's
CopyOnRead and CopyOnWrite features is beneficial when the
SegmentNodeStore isused?

The documentation indirectly suggests that CopyOnRead is only
beneficial with remote NodeStores (i.e. DocumentNodeStore). So the
question is whether the SegmentNodeStore implementation allows
sufficiently fast access to Lucene's index files, or whether the
associated overhead still makes CopyOnRead beneficial.

Thanks for any insights!

Regards
Julian

Re: Is Lucene CopyOnRead/CopyOnWrite beneficial with SegmentNodeStore?

Posted by Julian Sedding <js...@gmail.com>.

Thanks Chetan, that's very helpful.

Regards
Julian

On Mon, Nov 21, 2016 at 3:47 PM, Chetan Mehrotra
<ch...@gmail.com> wrote:
> In general its better that you use a BlobStore even with
> SegmenNodeStore. In that case CoR and CoW allows using Lucene's memory
> mapped FSDirectory support providing better performance.
>
> Some old numbers can be seen at [1]
>
> Chetan Mehrotra
> [1] https://issues.apache.org/jira/browse/OAK-1702?focusedCommentId=13965551&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13965551
>
>
> On Mon, Nov 21, 2016 at 8:03 PM, Julian Sedding <js...@apache.org> wrote:
>> Hi all
>>
>> Do we have experience or measurements to suggest that using Lucene's
>> CopyOnRead and CopyOnWrite features is beneficial when the
>> SegmentNodeStore isused?
>>
>> The documentation indirectly suggests that CopyOnRead is only
>> beneficial with remote NodeStores (i.e. DocumentNodeStore). So the
>> question is whether the SegmentNodeStore implementation allows
>> sufficiently fast access to Lucene's index files, or whether the
>> associated overhead still makes CopyOnRead beneficial.
>>
>> Thanks for any insights!
>>
>> Regards
>> Julian

Re: Is Lucene CopyOnRead/CopyOnWrite beneficial with SegmentNodeStore?

Posted by Chetan Mehrotra <ch...@gmail.com>.

In general its better that you use a BlobStore even with
SegmenNodeStore. In that case CoR and CoW allows using Lucene's memory
mapped FSDirectory support providing better performance.

Some old numbers can be seen at [1]

Chetan Mehrotra
[1] https://issues.apache.org/jira/browse/OAK-1702?focusedCommentId=13965551&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13965551


On Mon, Nov 21, 2016 at 8:03 PM, Julian Sedding <js...@apache.org> wrote:
> Hi all
>
> Do we have experience or measurements to suggest that using Lucene's
> CopyOnRead and CopyOnWrite features is beneficial when the
> SegmentNodeStore isused?
>
> The documentation indirectly suggests that CopyOnRead is only
> beneficial with remote NodeStores (i.e. DocumentNodeStore). So the
> question is whether the SegmentNodeStore implementation allows
> sufficiently fast access to Lucene's index files, or whether the
> associated overhead still makes CopyOnRead beneficial.
>
> Thanks for any insights!
>
> Regards
> Julian