class ActiveRecord::Base # Handle PG::UniqueViolation as well due to concurrency # find_or_create does find_by(hash) || create!(hash) # in some cases find will not find and multiple creates will be called # # note: Rails 6 has: https://github.com/rails/rails/blob/c83e30da27eafde79164ecb376e8a28ccc8d841f/activerecord/lib/active_record/relation.rb#L171-L201 # This means that in Rails 6 we would either use: # # create_or_find_by! (if we are generally creating) # # OR # # find_by(hash) || create_or_find_by(hash) (if we are generally finding) def self.find_or_create_by_safe!(hash) begin find_or_create_by!(hash) rescue PG::UniqueViolation, ActiveRecord::RecordNotUnique, ActiveRecord::RecordInvalid # try again cause another transaction could have passed by now find_or_create_by!(hash) end end # Execute SQL manually def self.exec_sql(*args) Discourse.deprecate("exec_sql should not be used anymore, please use DB.exec or DB.query instead!") conn = ActiveRecord::Base.connection sql = ActiveRecord::Base.send(:sanitize_sql_array, args) conn.raw_connection.async_exec(sql) end def exec_sql(*args) ActiveRecord::Base.exec_sql(*args) end # Executes the given block +retries+ times (or forever, if explicitly given nil), # catching and retrying SQL Deadlock errors. # # Thanks to: http://stackoverflow.com/a/7427186/165668 # def self.retry_lock_error(retries = 5, &block) begin yield rescue ActiveRecord::StatementInvalid => e if e.message =~ /deadlock detected/ && (retries.nil? || retries > 0) retry_lock_error(retries ? retries - 1 : nil, &block) else raise e end end end end