Немного обновленная версия ответа @ luca как минимум для Rails 4 (и, вероятно, Rails 5)
Поместите это в config/initializers/sql_logger.rb
:
connection = ActiveRecord::Base.connection
class << connection
alias :original_exec :execute
def execute(sql, *name)
# try to log sql command but ignore any errors that occur in this block
# we log before executing, in case the execution raises an error
begin
File.open(Rails.root.join("log/sql.log"), 'a') do |file|
file.puts Time.now.to_s + ": " + sql
end
rescue Exception => e
"Error logging SQL: #{e}"
end
# execute original statement
original_exec(sql, *name)
end
end