The problem with Parallel Gem and The MySQL server is running with the --read-only

[leesanghun6310]

How to resolve this problem..

Summary：I try to improvement one slowing api of my service via Parallel Gem

Problem：the error is occured in other part of the codes that I didn't added parallel gem's logic. occured code is include Create・Update・delete process

error message:

Mysql2::Error: The MySQL server is running with the --read-only option so it cannot execute this statement: "UPDATE ~~~"

def hogehoge(data)
  hogehoge = Parallel.map(data) do |data|
    ActiveRecord::Base.using(:slave1).connection.reconnect!
    ActiveRecord::Base.using(:master).connection.reconnect!

    adjust_fields() → contain business logic
  end
  ActiveRecord::Base.using(:slave1).connection.reconnect!
  ActiveRecord::Base.using(:master).connection.reconnect!

  return hogehoge
end

Info

1.DB's composition of My service is master and some slave (read only)

2.function which want to improvemnt is not include Create・Update・delete process

I also post Stack Overflow also
link：https://stackoverflow.com/posts/72766225

Thank you!

[grosser]

did not see something like that before, very strange ... I'm mostly expecting this to be either logic bug in adjust_fields or somehow queries being buffered in the connection

• use Parallel.map(data, in_processes: 0) do to see if it's caused by fork
• remove adjust_fields and see if it also happens
• simplify adjust_fields by removing more and more code until it stops happening

[grosser]

stackoverflow is gone, so I assume this was solved ...