MySQL on Amazon RDS

This page was generated from content adapted from the AWS Developer Guide

MySQL feature support

• Note The following lists are not exhaustive.

• Note System tables in the mysql schema can be in MyISAM storage.

• Important If your MySQL DB instance does not shut down normally, such as during a failover, then the buffer pool state will not be saved to disk. In this case, MySQL loads whatever buffer pool file is available when the DB instance is restarted. No harm is done, but the restored buffer pool might not reflect the most recent state of the buffer pool prior to the restart. To ensure that you have a recent state of the buffer pool available to warm the InnoDB cache on startup, we recommend that you periodically dump the buffer pool "on demand." You can create an event to dump the buffer pool automatically and on a regular interval. For example, the following statement creates an event named periodic_buffer_pool_dump that dumps the buffer pool every hour.

• Note Global transaction IDs are supported for all RDS for MySQL 5.7 versions, and for RDS for MySQL 8.0.26 and higher 8.0 versions.

MySQL versions

• Note Dates with only a month and a year are approximate and are updated with an exact date when it’s known.

• Note Dates with only a month and a year are approximate and are updated with an exact date when it’s known.

Connecting to a DB instance running MySQL

• Note For information on connecting to a MariaDB DB instance, see Connecting to a DB instance running the MariaDB database engine.

• Important Only use an unencrypted MySQL connection when the client and server are in the same VPC and the network is trusted. For information about using encrypted connections, see Connecting from the MySQL command-line client with SSL/TLS (encrypted).

Improving query performance with RDS Optimized Reads

• Note Both manual and automated RDS snapshots only contain engine files for persistent objects. The temporary objects created in the instance store aren't included in RDS snapshots.

Upgrading the MySQL DB engine

• Tip You can minimize the downtime required for DB instance upgrade by using a blue/green deployment. For more information, see Using Amazon RDS Blue/Green Deployments for database updates.

• Note Amazon RDS only takes DB snapshots if you have set the backup retention period for your DB instance to a number greater than 0. To change your backup retention period, see Modifying an Amazon RDS DB instance.

• Note You can only create MySQL version 5.7 and 8.0 DB instances with latest-generation and current-generation DB instance classes, in addition to the db.m3 previous-generation DB instance class. In some cases, you want to upgrade a MySQL version 5.6 DB instance running on a previous-generation DB instance class (other than db.m3) to a MySQL version 5.7 DB instance. In these cases, first modify the DB instance to use a latest-generation or current-generation DB instance class. After you do this, you can then modify the DB instance to use the MySQL version 5.7 database engine. For information on Amazon RDS DB instance classes, see DB instance classes.

• Note Amazon RDS runs all of these prechecks only for an upgrade from MySQL 5.7 to MySQL 8.0. For an upgrade from MySQL 5.6 to MySQL 5.7, prechecks are limited to confirming that there are no orphan tables and that there is enough storage space to rebuild tables. Prechecks aren't run for upgrades to releases lower than MySQL 5.7.

• Note Currently, automatic rollback after upgrade failure is supported only for MySQL 5.7 to 8.0 major version upgrades.

• Note When you are upgrading from MySQL version 5.7 to MySQL version 8.0, complete the prechecks before performing the upgrade. For more information, see Prechecks for upgrades from MySQL 5.7 to 8.0.

Importing data into a MySQL DB instance

• Note The 'mysql' system database contains authentication and authorization information required to log in to your DB instance and access your data. Dropping, altering, renaming, or truncating tables, data, or other contents of the 'mysql' database in your DB instance can result in error and might render the DB instance and your data inaccessible. If this occurs, you can restore the DB instance from a snapshot using the AWS CLI restore-db-instance-from-db-snapshot command. You can recover the DB instance using the AWS CLI restore-db-instance-to-point-in-time command.

• Note Using innodb_flush_log_at_trx_commit=0 causes InnoDB to flush its logs every second instead of at each commit. This provides a significant speed advantage, but can lead to data loss during a crash. Use with caution.

Working with MySQL replication

• Note You can configure replication to import databases from a MariaDB or MySQL instance that is external to Amazon RDS, or to export databases to such instances. For more information, see Importing data to an Amazon RDS MariaDB or MySQL database with reduced downtime and Exporting data from a MySQL DB instance by using replication.

Common DBA tasks for MySQL

• Note First verify that the error in question can be safely skipped. In a MySQL utility, connect to the read replica and run the following MySQL command.

• Important If you attempt to call mysql.rds_skip_repl_error and encounter the following error: ERROR 1305 (42000): PROCEDURE mysql.rds_skip_repl_error does not exist, then upgrade your MySQL DB instance to the latest minor version or one of the minimum minor versions listed in mysql.rds_skip_repl_error.

• Important Setting a nondefault value for this parameter can lead to replication inconsistency. Only set this parameter to a nondefault value if you have exhausted other options to resolve the problem and you are sure of the potential impact on your read replica's data.

Known issues and limitations

• Note Some existing DB instances have a lower limit. For example, MySQL DB instances created before April 2014 have a file and table size limit of 2 TB. This 2 TB file size limit also applies to DB instances or read replicas created from DB snapshots taken before April 2014, regardless of when the DB instance was created.