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awsdocs / amazon-rds-user-guide

The open source version of the Amazon RDS docs. You can submit feedback & requests for changes by submitting issues in this repo or by making proposed changes & submitting a pull request.
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Explanation for SQL_MODE default #160

Closed edhgoose closed 1 year ago

edhgoose commented 2 years ago

Hello, I noticed that the default for RDS mysql 5.7 and 8 parameter groups SQL_MODE option is different from the MySql default.

The default on MySql 5.7 is specified here: https://dev.mysql.com/doc/refman/5.7/en/faqs-sql-modes.html#faq-mysql-what-default-mode

The default for mysql 8 is specified here: https://dev.mysql.com/doc/refman/8.0/en/faqs-sql-modes.html#:~:text=The%20default%20SQL%20mode%20in,%2C%20%E2%80%9CServer%20SQL%20Modes%E2%80%9D.

Whereas the RDS default seems to be NO_ENGINE_SUBSTITUTION for both versions.

I understand how to change it, but I wondered if it was possible to document why the default is different, whether there are any benefits to the different default and why AWS recommends this default?

The reason for asking is that we noticed a difference between our local environments and AWS RDS and we're unsure on whether we should deliberately override the AWS recommendation. All the documentation I can find is about changing it, not why it's set like this.

nnat425 commented 1 year ago

Bump. We're seeing something similar in our system.

amylmill commented 1 year ago

Thanks for reaching out about this.

RDS might change the default values for some parameters. If you require different values, you can modify them in the database parameter group.

edhgoose commented 1 year ago

@amylmill we're asking for documentation of why the default is different and what the pros/cons/implications of it are.

We know we can change it.

Could we reopen this and have that documented please?

amylmill commented 1 year ago

@edhgoose Unfortunately, we do not publish the reasons for parameter differences.