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https://issues.apache.org/jira/browse/JCR-926?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12526412
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Thomas Mueller commented on JCR-926:
------------------------------------

Revision 574543: The FileDataStore now supports the configuration option 
'minRecordLength' (default: 100). 

Missing unit tests have been added, the test code coverage is now OK. A bug has 
been fixed (when importing, a temp file was created but never stored in the 
data store).

The setting 'org.jackrabbit.useDataStore' can now be enabled in my view, I will 
do this in a day or two unless there is a problem. Then, the new classes 
BLOBInResource, BLOBInTempFile, BLOBInMemory are used instead of BLOBValue. The 
file data store is still only used when configured in repository.xml. Temp 
files are still created in some cases (for example importing).

> Global data store for binaries
> ------------------------------
>
>                 Key: JCR-926
>                 URL: https://issues.apache.org/jira/browse/JCR-926
>             Project: Jackrabbit
>          Issue Type: New Feature
>          Components: core
>            Reporter: Jukka Zitting
>         Attachments: dataStore.patch, DataStore.patch, DataStore2.patch, 
> dataStore3.patch, dataStore4.zip, dataStore5-garbageCollector.patch, 
> internalValue.patch, ReadWhileSaveTest.patch
>
>
> There are three main problems with the way Jackrabbit currently handles large 
> binary values:
> 1) Persisting a large binary value blocks access to the persistence layer for 
> extended amounts of time (see JCR-314)
> 2) At least two copies of binary streams are made when saving them through 
> the JCR API: one in the transient space, and one when persisting the value
> 3) Versioining and copy operations on nodes or subtrees that contain large 
> binary values can quickly end up consuming excessive amounts of storage space.
> To solve these issues (and to get other nice benefits), I propose that we 
> implement a global "data store" concept in the repository. A data store is an 
> append-only set of binary values that uses short identifiers to identify and 
> access the stored binary values. The data store would trivially fit the 
> requirements of transient space and transaction handling due to the 
> append-only nature. An explicit mark-and-sweep garbage collection process 
> could be added to avoid concerns about storing garbage values.
> See the recent NGP value record discussion, especially [1], for more 
> background on this idea.
> [1] 
> http://mail-archives.apache.org/mod_mbox/jackrabbit-dev/200705.mbox/[EMAIL 
> PROTECTED]

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