什么是事务的默认ActiveRecord隔离级别

Question

对于PostgreSQL或MySQL的Ruby on Rails中的事务的默认隔离级别是什么？

active_record/connection_adapters /抽象/ database_statements.rb#L173

Answer 1

文件说明:

  # If your database supports setting the isolation level for a transaction, you can set
  # it like so:
  #
  #   Post.transaction(isolation: :serializable) do
  #     # ...
  #   end

代码是:

def transaction(requires_new: nil, isolation: nil, joinable: true)

默认值为,nil表示您使用的数据库的默认隔离级别.

MySQL的默认值是:repeatable_read.

Postgress的默认值是:read_committed.