Hi all, I have a process which creates a new object from a backgroundrb job. This object is versioned and the version is based on the existing objects in this table. For example, I''ve got a table called spreadsheets and it has a column called version. Each version is incremental and when a new one is created, the last version is found by a query. The problem I''m having is that when two background jobs are creating the same type of object, the read the table at the same time and thus assign the same version number to the object they are saving. I end up with two objects with the same version number. I cannot make it a unique column because it the table holds different objects with different version paths. Would locking the entire table be a good solution to this problem? It seems like it will cause timeout problems. If this is the way to go, what is the best "rails" way to accomplish this? If not, what suggestions do you have on how to solve this problem? Thanks much, Shagy -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On 17 Oct 2008, at 19:18, Shagy Moe <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:> > Hi all, > > I have a process which creates a new object from a backgroundrb job. > This object is versioned and the version is based on the existing > objects in this table. For example, I''ve got a table called > spreadsheets and it has a column called version. Each version is > incremental and when a new one is created, the last version is found > by > a query. > > The problem I''m having is that when two background jobs are creating > the > same type of object, the read the table at the same time and thus > assign > the same version number to the object they are saving. I end up with > two objects with the same version number. I cannot make it a unique > column because it the table holds different objects with different > version paths.Just create a unique index on the pair (or triple etc. ) of columns that you are interested in. Fred> > > Would locking the entire table be a good solution to this problem? It > seems like it will cause timeout problems. If this is the way to go, > what is the best "rails" way to accomplish this? If not, what > suggestions do you have on how to solve this problem? > > Thanks much, > > Shagy > -- > Posted via http://www.ruby-forum.com/. > > >--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
I think I''ve solved it by using :lock in the find like this:
spreadsheets = Spreadsheet.find(:all,
:conditions => ["parent_id = ?",
self.id],
:lock => "FOR UPDATE")
This tables uses acts_as_tree and originally I was just calling
self.children.
--
Posted via http://www.ruby-forum.com/.
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