maria-discuss team mailing list archive

[Gordan Bobic <gordan.bobic@xxxxxxxxx>]

On Wed, Jan 18, 2023 at 3:28 PM Dragos Pacher <dragosrp@xxxxxxxxx> wrote:
>
> Hello Gordan,
>
> Thank you for your advice. Your answer surprised me from 2 perspectives:
>
> 1. The following is coming from Plesk people in the default production install(!), I just changed it a bit on tuners advice.
> By default the setting is present in my.cnf:
>
> join_buffer_size                = 3M

Plesk people aren't database specialists and I wouldn't expect web
control panel developers to have a particularly extensive
understanding of database internals.
If whoever wrote MySQL Tuner doesn't have an adequate understanding of
such, what chance do developers who don't claim to be database
specialists have?

> 2. I see mysqltuner gaining more adoption - did not knew its that bad..

It really isn't (thankfully). The only setting you should be changing
away from defaults out of the box is innodb_buffer_pool_size.
You shouldn't be touching anything else unless you know exactly why
you are changing it.

> I will take your advice and leave the options as defaults - in the way Plesk meant it with the only change being to delete the join_buffer_size.
>
> What do you think about point nr 1?

Skipping name resolution?
That is fine if you don't define any of your users as logging in with
a hostname match.

Things like this will be fine if you skip the name resolve:
user@'1.2.3.4'
user@'1.2.3.%'

Things like this will NOT work:
user@'%.domain.com'

If all of your users are restricted by IP (or IP range), then you can
safely disable reverse DNS lookup and save yourself a millisecond or
two on every tcp database connection.