[xwiki-dev] [Proposal] Some/All fields in the database should be longer

[Artem Melentyev]

Hi.

Sergiu Dumitriu wrote:
> There are many properties stored in VARCHAR(255) fields, which sometimes
> isn't enough. This already causes
> http://jira.xwiki.org/jira/browse/XWIKI-883 . Changing to variable length
> field doesn't have any major side effects, as I know.
> 
> As pro arguments:
> 1. The size of the database will not increase
> 2. There are already some fields stored as mediumtext and longblob, so it's
> not something new in the database
> 3. The fewer limits there are, the better
> 4. Issues like XWIKI-883 will be fixed
> ... and maybe more
> 
> Is there something I'm missing that prevents this?

1. varchar(255) is supported across all db
2. I think there are some reasons that hibernate uses 255 as default
length of string.
3. biger types (clob, text) in many db has less functional possibilities
(ex: mssql) and less performance.
4. 255 is a performance barrier for some databases (mysql <5.0.3 and
some other db has a 255 length limit of varchar)

A good discussion of this problem is here:
http://osdir.com/ml/lang.groovy.grails.devel/2007-01/msg00029.html

So i think varchar(255) is normal and safe for many core xwiki fields.
(doc.names, etc).

XWIKI-883 can be resolved by change of StringProperty to
LargeStringProperty in Users/GroupsClass. (see attachment in jira)
Or we can rename LargeStringProperty to StringProperty :)

For what issues/fields else length increase can be useful?

PS: All this has no sense in XWikiJcrStore :)

-- 
  Artem Melentyev, UralSU