On 22 Oct 2008, at 19:41, Shagy Moe wrote:
>
> I've got some code that more or less looks like this:
I think it would be rather more helpful if you posted your code rather
than something that is more or less your code. The devil can be in the
details (random hint - watch out for files with screwed up line endings)
Fred
>
>
> class Project < ActiveRecord::Base
>
> def create_new_document
>
> document = Document.new
>
> document.attributes = { "project_id" => self.id,
> "attribute2" => "etc..."}
>
> if document.save
> new_document_page = DocumentPage.new
>
> new_document_page.attributes = { "document_id" =>
> new_document.id,
> "attribute2" => "etc..." }
>
> new_document_page.save
> end
> end
> end
>
> So, the strange thing is that even though the document.save call is
> sometimes failing and is wrapped in an "if" statement, it still
> tries to
> create the document page which ,of course, causes DB error since the
> new_document.id is nil. Also, I get "Mysql::Error: Cannot add or
> update
> a child row: a foreign key constraint fails" on the Project update sql
> because the document_id is the actual object_id instead of the id. The
> update statement is trying to put a value like "-618357298" instead of
> the document id (which doesn't exist since it didn't get saved.
>
> The reason I'm not wrapping both saves in a transaction is because I'm
> using attachment_fu to upload the document to amazon S3 and the save
> on
> the document times out while waiting for the document pages to save.
> The
> pages are also being uploaded to S3, and all this uploading takes
> time.
> I'm trying to take advantage of attachment_fu's automatic uploading
> when
> calling save instead of pushing this off to a background job.
>
> I'm running load testing by creating background jobs which create
> projects and thus documents and pages. Most of the time everything
> works fine, but under heavy load I get these errors but also rarely
> under light load.
>
> It seems like mysql is telling rails that the row was saved but it
> wasn't. The errors returned in regards to the document pages
> reference
> a document id that doesn't exist in the database. So, I see id skips
> in
> the document table. For instance, the document page error references
> document id 939 and the ids in the document table go 932, 934, 935...
>
> In load testing, I have up to 5 app servers selecting from, inserting
> into and updating the database. As I said, the errors are less with
> medium load, but also happen randomly under very light load. I'm
> using
> the deadlock_retry plugin which resolved some deadlocking issues I was
> having.
>
> Ok, so has anyone experienced something similar? It seems as though I
> need to beef up the DB server, but the errors on light load suggest
> something else.
>
> Any feedback is much appreciated.
>
> Thanks,
>
> Shagy
> --
> Posted via http://www.ruby-forum.com/.
>
> >
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