# Problem with ActiveRecord and PDFWriter **URL:** \ **Category:** Ruby\ **Created:** [December 4, 2006, 12:49pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241 "2006-12-04T12:49:01Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 4, 2006, 12:49pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/1 "2006-12-04T12:49:01Z")
Probably this has been discussed earlier elsewhere. I am having some problem while using PDFWriter in rails. following code throws error: my\_table.render\_on(pdf) In short, I get error: no marshal\_dump is defined for class Mutex RAILS\_ROOT: /home/hemant/foo\_app/config/… Application Trace | Framework Trace | Full Trace /usr/local/lib/site\_ruby/1.8/transaction/simple.rb:370:in `dump' /usr/local/lib/site_ruby/1.8/transaction/simple.rb:370:in `start\_transaction’ /usr/local/lib/site\_ruby/1.8/transaction/simple/group.rb:89:in `start_transaction' /usr/local/lib/site_ruby/1.8/transaction/simple/group.rb:89:in `start\_transaction’ /usr/local/lib/site\_ruby/1.8/pdf/simpletable.rb:397:in `render_on' #{RAILS_ROOT}/app/controllers/analytics_controller.rb:266:in `pdf\_download’ #{RAILS\_ROOT}/app/controllers/analytics\_controller.rb:224:in `pdf\_download’ /usr/bin/mongrel\_rails:18 It turns out that, people in past also had problems when using PDFWriter under rails, because rails bundles its own version of Simple Transaction(simple.rb) package. But the package bundled with rails is not complete and hence the libraries that need full blown simple transaction package more or less break. I have also tried patching activerecord with this patch: [http://dev.rubyonrails.org/attachment/ticket/4732/do-not-require-transaction-simple-if-already-loaded.patch](http://dev.rubyonrails.org/attachment/ticket/4732/do-not-require-transaction-simple-if-already-loaded.patch) doesn’t seem to work. I am also using LoginEngine _code_ (i.e just the code, not the engine itself ,for admin interface). But I have got rid of most of the transaction statements from the code for the time being. So, I am curious… 1. If the problem is in my code? 2. If there is a problem with PDFWriter or AR 3. Or the said patch simply doesn’t work What are my options? ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 4, 2006, 2:17pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/2 "2006-12-04T14:17:13Z")
On 12/4/06, hemant [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > no marshal\_dump is defined for class Mutex You look like you’re doing something threaded. I don’t know if that’s Rails doing it for you, but you can’t dump either threads or mutexes in Ruby. You _must_ have the latest Transaction::Simple (and Rails _really_ needs to remove it and add the latest version as a dependency; I’m getting ready to release a new version that’s even more useful and PDF::Writer _will_ depend on it moving forward). > 1. If the problem is in my code? > 2. If there is a problem with PDFWriter or AR > 3. Or the said patch simply doesn’t work I suspect 1, 2 (with respect to ActiveRecord bundling Transaction::Simple; something I’ve asked them to fix a long time ago), and 3. -austin ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 11, 2006, 2:45pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/3 "2006-12-11T14:45:33Z")
Austin Z. a écrit : > > 1. If the problem is in my code? > > 2. If there is a problem with PDFWriter or AR > > 3. Or the said patch simply doesn’t work > > I suspect 1, 2 (with respect to ActiveRecord bundling > Transaction::Simple; something I’ve asked them to fix a long time > ago), and 3. > > -austin Hello, I have exactly the same problem. But the problem doesn’t appear if I test in local with webrick (in development or production environment) but it appears with apache+mongrel. All the libraries are in the same version on both configuration (1.1.6 for rails, 1.3.0 for transaction-simple and 1.1.3 for pdf-writer). I really don’t know what to do. Any help ? Thanks in advance. ++ Jerome ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 11, 2006, 6:49pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/4 "2006-12-11T18:49:16Z")
On 12/11/06, Jérôme Loyet [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > dependency; I’m getting ready to release a new version that’s even > > -austin > > I really don’t know what to do. > > Any help ? I have tried in vain to patch AR, but it doesn’t seem to ( sorry for violating DRY) Hmm…there are couple of things which are threaded in my app, but they don’t run within rails. For example: 1. Mongrel itself is threaded. 2. Backgroundrb I am using, which is threaded. 3. I am using a third party charting thingy, which is threaded. But when I went through code of PDFWriter, it seemed that indeed they create a mutex and start the transaction. Now, there ain’t any mutexes anywhere in my code and the library I am using is well tucked away. So only guy creating a mutex was PDFWriter and i suspect PDFWriter is only trying to dump it. I am really out of ideas, here… if anyone can help? ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 11, 2006, 9:15pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/5 "2006-12-11T21:15:41Z")
On 12/12/06, Austin Z. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Good point Austin, and honestly I was populating some PDF variables from session, But then I removed those lines from code and still the error. If you don’t mind can I send you the code offlist and If you can have a look? ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 11, 2006, 8:39pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/6 "2006-12-11T20:39:33Z")
On 12/11/06, hemant [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > But when I went through code of PDFWriter, it seemed that indeed they > create a mutex and start the transaction. Now, there ain’t any mutexes > anywhere in my code and the library I am using is well tucked away. So > only guy creating a mutex was PDFWriter and i suspect PDFWriter is > only trying to dump it. Trust me. PDF::Writer isn’t trying to dump a mutex here (this is something I know well). Have you put a PDF variable in a session or something like that? -austin ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 11, 2006, 9:31pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/7 "2006-12-11T21:31:44Z")
On 12/11/06, hemant [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > something like that? > > Good point Austin, and honestly I was populating some PDF variables > > from session, But then I removed those lines from code and still the > > error. > > If you don’t mind can I send you the code offlist and If you can have a look? Sure. Don’t expect a quick response, though. I’ve written one Rails application. -austin ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 11, 2006, 10:23pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/8 "2006-12-11T22:23:57Z")
> Transaction::Simple; something I’ve asked them to fix a long time > ago), and 3. You could probably distribute a Rails plugin with PDF::Writer as a workaround. Unless upgrading Transaction::Simple breaks Rails? ---
**Author:** ![gnufied](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/ea666f/32.png) [@gnufied](https://www.ruby-forum.com/u/gnufied)\ **Post date:** [December 11, 2006, 10:36pm UTC](https://www.ruby-forum.com/t/problem-with-activerecord-and-pdfwriter/78241/9 "2006-12-11T22:36:03Z")
On 12/11/06, Giles B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > Transaction::Simple; something I’ve asked them to fix a long time > > ago), and 3. > > You could probably distribute a Rails plugin with PDF::Writer as a > workaround. Unless upgrading Transaction::Simple breaks Rails? I will not be doing so. I provide a _Ruby_ library. I have told the Rails folks that they should be using Transaction::Simple library as a gem, because I guarantee compatibility. -austin