On Sunday, October 25, 2015 at 8:10:59 AM UTC-7, Adarsh Pandit wrote:
>
> Hello!
>
> I am updating a large number of records (~11k) with responses from an 
> external API.
>
> For context, each Company has many Applicants. Applicant has a 
> `job_application` JSONB column. I am using Postgres 9.4.5, the 
> `sequel-rails` gem, and the most recent Sequel.
>
> I'm running the below and seeing surprising behavior, so the code is:
>
>     Applicant.where(job_application: nil).count # => 11,000
>
>     company.applicants_dataset.where(job_application: nil).use_cursor.each 
> do |applicant|
>       job_application = get_applications_from_external_api(applicant)
>       applicant.update(job_application: job_application)
>
>     end
>
>     # Exit early after a few records update
>    Applicant.where(job_application: nil).count # => 11,000
>
>
>
> I'm seeing rollback of EVERY update made to the `job_application` JSONB 
> column in Applicant if the block exits with an error.
>
> My config in `application.rb` is
>
>     config.sequel.after_connect = proc do
>       Sequel::Model.db.extension :pg_json
>       Sequel.extension :pg_json_ops
>       Sequel::Model.plugin :timestamps, update_on_create: true
>     end
>
>
>
> Feels like this whole thing is run as a transaction, but I have not set it 
> do do so anywhere (other than in the `spec_helper`). 
> I know this batch update will periodically fail due to API vagaries - any 
> help on saving the results if there is an error?
>

You probably want to pass :hold=>true to use_cursor, otherwise use_cursor 
will use a transaction.  See 
http://sequel.jeremyevans.net/rdoc-adapters/classes/Sequel/Postgres/Dataset.html#method-i-use_cursor

Thanks,
Jeremy

-- 
You received this message because you are subscribed to the Google Groups 
"sequel-talk" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sequel-talk.
For more options, visit https://groups.google.com/d/optout.

Reply via email to