thr3ads.net - Rails - Wrap Migration in Transaction [Sep 2006]

If this information is useful, please help other people find it:
Share via:

Caleb

2006-Sep-29 19:30 UTC

Wrap Migration in Transaction

Correct me if I''m wrong, but it appears to me that rake migrate does
not
wrap its execution in a transaction.  Is this right?  If so, why not? 
And, is it possible at all to wrap a rake migrate in a DB transaction?

I''ve tried:
def self.up
  ActiveRecord::Base.transaction do
    ......migration stuff......
    raise "My Error"
  end
end

"My Error" is thrown but the transaction is not rolled back.  Is
raising
an exception the proper way to invoke an ActiveRecord transaction 
rollback?

I''ve also tried doing:
ActiveRecord::Base.transation do
  %x[rake migrate]
end

But this, obviously, doesn''t work since %x[rake migrate] spanws a new 
process outside of the scope of the transactioning.

Any ideas?

-- 
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
-~----------~----~----~----~------~----~------~--~---

Jean-François

2006-Sep-30 14:24 UTC

head link

Re: Wrap Migration in Transaction

Hello Caleb,
> I've also tried doing:
> ActiveRecord::Base.transation do
>   %x[rake migrate]
> end
>
> But this, obviously, doesn't work since %x[rake migrate]
> spanws a new process outside of the scope of the
> transactioning.
>
> Any ideas?
To invoke a Rake task in a migration, you can do :

def self.up
   Rake::Task[my_task].invoke
end

I have tried with : Rake::Task['stats'].invoke and it works.
However, it can be dangerous, what will happen with a
Rake::Task['db:migrate'] ? infinite loop ? :) it could be a mess...
I think a rake db task would work, but you have to be careful.

HTH,
     -- Jean-François.

-- 
À la renverse.

--~--~---------~--~----~------------~-------~--~----~
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@googlegroups.com
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk
-~----------~----~----~----~------~----~------~--~---

Fred

2006-Sep-30 16:36 UTC

head link

Re: Wrap Migration in Transaction

Caleb wrote:> Correct me if I''m wrong, but it appears to me that rake migrate
does not
> wrap its execution in a transaction.  Is this right?  If so, why not? 
> And, is it possible at all to wrap a rake migrate in a DB transaction?
> I don''t know if this is true of all databases, but for mysql this
won''t
be possible most of the time (although it would be really useful). The 
problem with mysql is that there are a bunch of statements that cause an 
implicit commit and this list includes most of the things you do in a 
migration: adding/removing indexes, ALTER TABLE, creating tables. So 
even if you do wrap your migration in a transaction, just about anything 
you do in your migration will commit the transaction.

Fred

-- 
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
-~----------~----~----~----~------~----~------~--~---

Caleb

2006-Oct-02 17:05 UTC

head link

Re: Wrap Migration in Transaction

Jean-François wrote:> To invoke a Rake task in a migration, you can do :
> 
> def self.up
>    Rake::Task[my_task].invoke
> end
When I do the following from the Rails console:
Rake::Task[''stats''].invoke

I get the following error:
RuntimeError: Don''t know how to build task ''stats''
        from 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.7.1/lib/rake.rb:1449:in `[]''
        from 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.7.1/lib/rake.rb:455:in `[]''
        from (irb):

While something like Rake::Task[my_task].invoke is exactly what I''m 
trying to do, I think you got things a bit backwards.  I need to invoke 
Rake migrate from another class, not invoke a Rake task from within a 
migration.  Any idea as to why I''m getting the console error above? 
I''d
assume (maybe a poor assumption?) that once I can get it to work in the 
Rails console then it should work from any line of code in my Rails app.

-- 
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@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk
-~----------~----~----~----~------~----~------~--~---

Caleb

2006-Oct-02 17:08 UTC

head link

Re: Wrap Migration in Transaction

Fred wrote:> The problem with mysql is that there are a bunch of statements that cause
an
> implicit commit and this list includes most of the things you do in a 
> migration: adding/removing indexes, ALTER TABLE, creating tables. So 
> even if you do wrap your migration in a transaction, just about anything 
> you do in your migration will commit the transaction.
Good point!  Fortunately, I''m using these migrations to do data changes
(INSERT/UPDATE/DELETE), NOT SCHEMA changes (ALTER/DROP/CREATE). 
However, I do reset the AUTO_INCREMENT values by using an ALTER TABLE 
command?  Do all ALTER TABLE commands in MySQL imply a transaction 
commit?  Or does it depend on how you alter the table?


-- 
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
-~----------~----~----~----~------~----~------~--~---

Frederick Cheung

2006-Oct-02 17:21 UTC

head link

Re: Wrap Migration in Transaction

Caleb wrote:> Fred wrote:
>> The problem with mysql is that there are a bunch of statements that
cause an
>> implicit commit and this list includes most of the things you do in a 
>> migration: adding/removing indexes, ALTER TABLE, creating tables. So 
>> even if you do wrap your migration in a transaction, just about
anything
>> you do in your migration will commit the transaction.
> 
> Good point!  Fortunately, I''m using these migrations to do data
changes
> (INSERT/UPDATE/DELETE), NOT SCHEMA changes (ALTER/DROP/CREATE). 
> However, I do reset the AUTO_INCREMENT values by using an ALTER TABLE 
> command?  Do all ALTER TABLE commands in MySQL imply a transaction 
> commit?  Or does it depend on how you alter the table?
Official docs are at 
http://mysql.speedbone.de/doc/refman/5.0/en/implicit-commit.html they 
seem to say that any ALTER TABLE statement will cause the implicit 
commit

Fred

-- 
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
-~----------~----~----~----~------~----~------~--~---

Caleb

2006-Oct-02 17:51 UTC

head link

Re: Wrap Migration in Transaction

Caleb said:> I need to invoke Rake migrate from another class, not invoke a Rake task
from
> within a migration.  Any idea as to why I''m getting the console
error above?
> I''d assume (maybe a poor assumption?) that once I can get it to
work in the
> Rails console then it should work from any line of code in my Rails app.
Anyone have any ideas on this?

-- 
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
-~----------~----~----~----~------~----~------~--~---

Jeff Dean

2006-Oct-02 18:39 UTC

head link

Re: Wrap Migration in Transaction

For data-only modifications, you can use a simple transaction do statement
like anywhere else:

class TransactionTest < ActiveRecord::Migration
  def self.up
    transaction do
      execute "insert into some_table(some_column)
values(''some_value'')"
    end
  end

  def self.down
  end
end

For a cool slideshow that deals with this a little check out page 18 of:

http://www.chariotsolutions.com/slides/PhillyOnRails-Migrations.pdf

If you want to make the switch to a database that supports transactions for
ddl (like postgres), you can also install this plugin and it should solve
most of your problems:

http://www.redhillconsulting.com.au/rails_plugins.html#transactional_migrations

I haven''t tried that latest plugin, but I regularly use transaction do
for
my more complicated data manipulations scripts.

Jeff

On 10/2/06, Caleb
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:>
>
> Caleb said:
> > I need to invoke Rake migrate from another class, not invoke a Rake
task
> from
> > within a migration.  Any idea as to why I''m getting the
console error
> above?
> > I''d assume (maybe a poor assumption?) that once I can get it
to work in
> the
> > Rails console then it should work from any line of code in my Rails
app.
>
> Anyone have any ideas on this?
>
> --
> Posted via http://www.ruby-forum.com/.
>
> >


-- 
Jeff Dean
917.414.7801


--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---

Rails - Sep 2006 - Wrap Migration in Transaction

Wrap Migration in Transaction

Re: Wrap Migration in Transaction

Re: Wrap Migration in Transaction

Re: Wrap Migration in Transaction

Re: Wrap Migration in Transaction

Re: Wrap Migration in Transaction

Re: Wrap Migration in Transaction

Re: Wrap Migration in Transaction