[
https://issues.apache.org/jira/browse/OAK-2808?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15994452#comment-15994452
]
Chetan Mehrotra commented on OAK-2808:
--------------------------------------
bq. What about if we do regular index updates as we do now every few seconds,
but only locally (on the local file system), and only persist the index (to the
repository) every x minutes.
That would be tricky as the async indexer would have released the checkpoint
and move forward assuming index is upto date. So in case of any crash it would
not be possible to determine what needs to be indexed.
> Active deletion of 'deleted' Lucene index files from DataStore without
> relying on full scale Blob GC
> ----------------------------------------------------------------------------------------------------
>
> Key: OAK-2808
> URL: https://issues.apache.org/jira/browse/OAK-2808
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: lucene
> Reporter: Chetan Mehrotra
> Assignee: Thomas Mueller
> Labels: datastore, performance
> Fix For: 1.8
>
> Attachments: copyonread-stats.png, OAK-2808-1.patch
>
>
> With storing of Lucene index files within DataStore our usage pattern
> of DataStore has changed between JR2 and Oak.
> With JR2 the writes were mostly application based i.e. if application
> stores a pdf/image file then that would be stored in DataStore. JR2 by
> default would not write stuff to DataStore. Further in deployment
> where large number of binary content is present then systems tend to
> share the DataStore to avoid duplication of storage. In such cases
> running Blob GC is a non trivial task as it involves a manual step and
> coordination across multiple deployments. Due to this systems tend to
> delay frequency of GC
> Now with Oak apart from application the Oak system itself *actively*
> uses the DataStore to store the index files for Lucene and there the
> churn might be much higher i.e. frequency of creation and deletion of
> index file is lot higher. This would accelerate the rate of garbage
> generation and thus put lot more pressure on the DataStore storage
> requirements.
> Discussion thread http://markmail.org/thread/iybd3eq2bh372zrl
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
