Hi Denis,
Just of curiosity, how did you choose liquibase from the rest? E.g.
http://code.google.com/p/dbmigrate/
http://www.dbmaintain.org/overview.html
http://code.google.com/p/flyway/
and etc ...
What were pros and cons?
Regards,
Roman
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Denis
Gervalle
Sent: Thursday, January 26, 2012 21:29 PM
To: XWiki Developers
Subject: [xwiki-devs] [Proposal] Use liquibase to manage the database schema
While trying to reduce the likelihood of duplicate ids for documents, and
extending my patch to provide a proper solution for objects, I fall on a really
unexpected issue: the type of the object identifiers are Integer where those of
documents are Long. This is completely abnormal since we have several objects
per documents, and therefore we need more distinct ids for objects than
documents.
I have therefore upgraded the ids of objects to use Long, and provide an
implementation that use the lowest 64bits of an MD5 key for object in the same
way I do for documents. This implementation introduce two new
serializer: UidStringEntityReferenceSerializer and
LocalUidStringEntityReferenceSerializer.
I have also bridged the statistics that derived from objects. The new
implementation works perfectly on a new database but...
... I am unable to provide a proper migration procedure, since hibernate cannot
manage changing the types of existing columns. It does not complains during
schema update, it simply do nothing about them. And later the data migration
breaks since my hashes cannot fit in the database properly. After thorough
googling, I understand that hibernate schema updates were not made for
production use and are really limited opposed to the general idea we had of it.
Since I am currently stucked, I propose to move ahead and use a new tool to
properly manage our database schema upgrade:
http://www.liquibase.org/
Liquibase is Apache licensed and provide a database agnostic version system for
migrating databases. It does not works like a diff tool, but more like a patch
tool, where you provide several XML description of your wanted changes and it
manage to apply or rollback there changes in an ordered manner to upgrade the
database to the latest schema.
There is several way to apply these changes and I would like to see if it could
be integrated in our current migration procedure, or at least as an independent
listener.
WDYT ?
--
Denis Gervalle
SOFTEC sa - CEO
eGuilde sarl - CTO
_______________________________________________
devs mailing list
[email protected]
http://lists.xwiki.org/mailman/listinfo/devs
_______________________________________________
devs mailing list
[email protected]
http://lists.xwiki.org/mailman/listinfo/devs
