Discourse - import - exception: PG::Error: ERROR: duplicate key value violates unique constraint "index_draft_sequences_on_user_id_and_draft_key"

backtrace

/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/logster-0.0.10/lib/logster/logger.rb:47:in `add'
/usr/local/lib/ruby/2.0.0/logger.rb:454:in `error'
/var/www/discourse/config/initializers/sidekiq.rb:52:in `call'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/sidekiq-3.1.3/lib/sidekiq/exception_handler.rb:20:in `block in handle_exception'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/sidekiq-3.1.3/lib/sidekiq/exception_handler.rb:18:in `each'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/sidekiq-3.1.3/lib/sidekiq/exception_handler.rb:18:in `handle_exception'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/sidekiq-3.1.3/lib/sidekiq/processor.rb:61:in `rescue in process'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/sidekiq-3.1.3/lib/sidekiq/processor.rb:65:in `process'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/celluloid-0.15.2/lib/celluloid/calls.rb:25:in `public_send'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/celluloid-0.15.2/lib/celluloid/calls.rb:25:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/celluloid-0.15.2/lib/celluloid/calls.rb:122:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/celluloid-0.15.2/lib/celluloid/actor.rb:322:in `block in handle_message'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/celluloid-0.15.2/lib/celluloid/actor.rb:416:in `block in task'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/celluloid-0.15.2/lib/celluloid/tasks.rb:55:in `block in initialize'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/celluloid-0.15.2/lib/celluloid/tasks/task_fiber.rb:13:in `block in create'

info

exception: PG::Error: ERROR:  duplicate key value violates unique constraint "index_draft_sequences_on_user_id_and_draft_key"
DETAIL:  Key (user_id, draft_key)=(-1, topic_38679) already exists.
: INSERT INTO "draft_sequences" ("draft_key", "sequence", "user_id") VALUES ($1, $2, $3) RETURNING "id"
context: {"retry"=>true, "queue"=>"default", "class"=>"Sidekiq::Extensions::DelayedClass", "args"=>["---\n- !ruby/class 'Jobs::PullHotlinkedImages'\n- :delayed_perform\n- - :post_id: 311856\n    :bypass_bump: false\n    :current_site_id: default\n"], "jid"=>"a26e279dba6c645dc9c1fe32", "enqueued_at"=>1403402457.223576, "error_message"=>"PG::Error: ERROR:  duplicate key value violates unique constraint \"index_draft_sequences_on_user_id_and_draft_key\"\nDETAIL:  Key (user_id, draft_key)=(-1, topic_38679) already exists.\n: INSERT INTO \"draft_sequences\" (\"draft_key\", \"sequence\", \"user_id\") VALUES ($1, $2, $3) RETURNING \"id\"", "error_class"=>"ActiveRecord::RecordNotUnique", "failed_at"=>1403402760.840269, "retry_count"=>0}
backtrace: /var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:827:in `get_last_result'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:827:in `block in exec_cache'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/abstract_adapter.rb:373:in `block in log'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activesupport-4.1.1/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/abstract_adapter.rb:367:in `log'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:824:in `exec_cache'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:138:in `exec_query'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:180:in `exec_insert'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/abstract/database_statements.rb:105:in `insert'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/abstract/query_cache.rb:14:in `insert'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/relation.rb:64:in `insert'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/persistence.rb:502:in `create_record'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/attribute_methods/dirty.rb:87:in `create_record'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/callbacks.rb:306:in `block in create_record'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activesupport-4.1.1/lib/active_support/callbacks.rb:82:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/callbacks.rb:306:in `create_record'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/timestamp.rb:57:in `create_record'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/persistence.rb:482:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/callbacks.rb:302:in `block in create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activesupport-4.1.1/lib/active_support/callbacks.rb:82:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/callbacks.rb:302:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/persistence.rb:103:in `save'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/validations.rb:51:in `save'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/attribute_methods/dirty.rb:21:in `save'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/transactions.rb:268:in `block (2 levels) in save'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/transactions.rb:329:in `block in with_transaction_returning_status'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `block in transaction'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/abstract/database_statements.rb:219:in `within_new_transaction'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/transactions.rb:208:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/transactions.rb:326:in `with_transaction_returning_status'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/transactions.rb:268:in `block in save'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/transactions.rb:283:in `rollback_active_record_state!'
/var/www/discourse/vendor/bundle/ruby/2.0.0/gems/activerecord-4.1.1/lib/active_record/transactions.rb:267:in `save'
/var/www/discourse/app/models/draft_sequence.rb:10:in `next!'
/var/www/discourse/app/models/post.rb:406:in `advance_draft_sequence'
/var/www/discourse/lib/post_revisor.rb:28:in `revise!'
/var/www/discourse/app/models/post.rb:313:in `revise'
/var/www/discourse/app/jobs/regular/pull_hotlinked_images.rb:87:in `execute'
/var/www/discourse/app/jobs/base.rb:131:in `block (2 levels) in perform'