Occurs on PostgreSQL, not SQLite.
It looks like the ID is generated in the SQL instead of using a sequence, which ends up with a duplicate? In this example, I already had a single domain with ID=1, added a second (foo.example.com) within an org/loc context and the same ID was assigned.
SQL (2.2ms) INSERT INTO "domains" ("created_at", "dns_id", "fullname", "hostgroups_count", "hosts_count", "id", "name", "updated_at") VALUES ($1, $2, $3, $4, $5, $6, $7, $8) RETURNING "id" [["created_at", Thu, 20 Mar 2014 08:24:47 UTC +00:00], ["dns_id", nil], ["fullname", ""], ["hostgroups_count", 0], ["hosts_count", 0], ["id", 1], ["name", "foo.example.com"], ["updated_at", Thu, 20 Mar 2014 08:24:47 UTC +00:00]]
PGError: ERROR: duplicate key value violates unique constraint "domains_pkey"
: INSERT INTO "domains" ("created_at", "dns_id", "fullname", "hostgroups_count", "hosts_count", "id", "name", "updated_at") VALUES ($1, $2, $3, $4, $5, $6, $7, $8) RETURNING "id"
(0.1ms) ROLLBACK
Operation FAILED: ERROR: duplicate key value violates unique constraint "domains_pkey"
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:1171:in `get_last_result'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:1171:in `exec_cache'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:665:in `block in exec_query'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `block in log'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract_adapter.rb:275:in `log'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:663:in `exec_query'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/database_statements.rb:63:in `exec_insert'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/database_statements.rb:90:in `insert'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/query_cache.rb:14:in `insert'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/relation.rb:66:in `insert'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/persistence.rb:366:in `create'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/timestamp.rb:57:in `create'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/callbacks.rb:268:in `block in create'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:403:in `_run__3837851857623516097__create__137576595651868549__callbacks'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:405:in `__run_callback'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:385:in `_run_create_callbacks'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:81:in `run_callbacks'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/callbacks.rb:268:in `create'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/persistence.rb:347:in `create_or_update'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/callbacks.rb:264:in `block in create_or_update'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:425:in `_run__3837851857623516097__save__137576595651868549__callbacks'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:405:in `__run_callback'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:385:in `_run_save_callbacks'
/opt/rh/ruby193/root/usr/share/gems/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:81:in `run_callbacks'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/callbacks.rb:264:in `create_or_update'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/persistence.rb:84:in `save'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/validations.rb:50:in `save'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/attribute_methods/dirty.rb:22:in `save'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/transactions.rb:241:in `block (2 levels) in save'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/transactions.rb:208:in `transaction'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/transactions.rb:241:in `block in save'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/transactions.rb:252:in `rollback_active_record_state!'
/opt/rh/ruby193/root/usr/share/gems/gems/activerecord-3.2.8/lib/active_record/transactions.rb:240:in `save'
/usr/share/foreman/app/controllers/domains_controller.rb:16:in `create'
Updated by 
Updated by 
Updated by Dominic Cleal about 11 years ago
Updated by Joseph Magen about 11 years ago
Updated by 
Updated by Ohad Levy about 11 years ago
Updated by Marek Hulán over 8 years ago