grasp(eo) versioning system

Versioning system in Graspeo

Nikita Grishin, EPFL, 17.04.2014 Supervised by Andrii Vozniuk

Motivation

Every document management system has the versioning.

Motivation


Various resources from various locations need to be tracked back

Motivation


Various resources from various locations need to be tracked back

The collaborators system implies the recovery system

State of the art

• Mercurial, SVN/CVS!

• On document change, only modifications are saved

• Easy to track modifications

• Difficult to recover old versions

• Git

• On file change, new version of file is created

• Easy to recover old versions

• Difficult to track modifications

• Mercurial, SVN/CVS!

• On document change, only modifications are saved

• Easy to track modifications

• Difficult to recover old versions

• Git

• On file change, new version of file is created

• Pointer to the last version

• Easy to recover old versions

• Difficult to track modifications

Only for text documents.

Works very bad with media content.

• Snapshots: new version of document for each modification


• Recovering the older version: creates a copy of the asked version on the top of the last version



• Some old versions can be removed by Google in case of lack of space



• Some old versions can be removed by Google in case of lack of space

• Only users that can edit the document can see its modification history

• Hard drive snapshots.

Apple TimeMachine


• Keeps:

• Hourly backups for last 24 hours

Apple TimeMachine


• Keeps:


• Daily backups for the past month

Apple TimeMachine


• Keeps:



• Weekly backups until your backup drive is full.

Apple TimeMachine


• Keeps:



• Weekly backups until your backup drive is full.

• When your backup drive is full, TimeMachine removes old backups to free space.

Apple TimeMachine

Graspeo versioning system solution

Versioning

Graspeo versioning system solution• Snapshots: new version of item for

each modification

Versioning


each modification

• Any modification in Space generates a new version of Space and of all its parents

Versioning


each modification


• Each file modification creates a new version of that file

Versioning


each modification



• File or Space removing affects only space. The file itself stays in the database

Versioning


each modification



• File or Space removing affects only space. The file itself stays in the database

• Recover the old version remains to clone it and put on the top of versions tree

Versioning

How does it work?• Each item has two new fields: originId and version


• OriginId: id of the first version of item. It is used to track the item modifications during the time. Is the same for all versions of the item



• Version: Value indicating the version number of the item.




• Path value represents now the logical path: it is constructed of originId values (not id).




• Path value represents now the logical path: it is constructed of originId values (not id).

• So now a query on path will return all children of all versions of the item.

How does it work?• New version of item contains the same data that the previous

version, except id and version fields:

• id field is completely new and unique

• version field is incremented by 1

How does it work?• New version of item contains the same data that the previous

version, except id and version fields:

• id field is completely new and unique

• version field is incremented by 1

• Parents are updated recursively:

• New version of parent is created

• Subitems array of parent’s new version document is updated in order to remove an id of previous version child

How does it work?• GridFS is implemented in order to store all files versions.

• Every version of each file is stored in GridFS with its unique id

• Resource document has a field gfsId that references to the file in GridFS

How does it work?• GridFS is implemented in order to store all files versions.

• Every version of each file is stored in GridFS with its unique id

• Resource document has a field gfsId that references to the file in GridFS

• On the file system, only the last version of file is present.

• When file’s version is updated, old version is removed from file system storage and is replaced by the new version from GridFS

• Motivation: BitTorrent Sync, performance

Future PlansSemester project deadline: 06.06.2014

Future Plans• Implement versioning while removing items (end of this week)


• Create API for versions recovery (end of April)



• Create a front-end for versioning



• Create a front-end for versioning

• Implement versioning while using BTSync

Thank you for your attentionQuestions

grasp(eo) versioning system

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