Comments on: New MySQL 8.0 innodb_dedicated_server Variable Optimizes InnoDB from the Get-Go

By: Janet Campbell

Janet Campbell — Thu, 04 Apr 2019 23:09:37 +0000

Serious question: how on earth is O_DIRECT_NO_FSYNC being done safely?

O_DIRECT does not and has never implied that the writes will been made durable by the time the write call returns. It bypasses host buffer cache, but does not flush the caches on the storage device. It’s possible for writes done using O_DIRECT to hang out there indefinitely until something issues a cache flush.

So, is there something done at the end of the writes that forces everything to the platters? If not, this sounds like a bug. O_DIRECT gives no durability guarantee whatsoever by itself.

By: Bill Karwin

Bill Karwin — Wed, 11 Apr 2018 15:38:21 +0000

I predict this option will become the new “magic_quotes”.

By: Baruch

Baruch — Sun, 01 Apr 2018 04:37:02 +0000

In reply to Jacob.

The name of the varibale is innodb_dedicated_server
As dedicated server per MySQL instance.
So it’s safe to assume that the MySQL will not be tuned for multiple MySQL instances on one server if you use this vaiable .

By: Jacob

Jacob — Tue, 27 Mar 2018 18:52:39 +0000

I wonder what the author actually means by “the RAM size of the system”?

Perhaps, “system” means the host that runs MySQL server.
However, what if the host runs multiple MySQL server instances?

Are those variables aware about other servers that have demand for the RAM as well?

By: SuperQ

SuperQ — Tue, 27 Mar 2018 00:00:45 +0000

Does this new auto-tuning understand inspecting cgroup limits?