# Aurora MySQL database engine updates: 2017-04-05 (version 1.12) (Deprecated)
Aurora MySQL updates: 2017-04-05 (version 1.12) (Deprecated)

**Version:** 1.12

Aurora MySQL 1.12 is now the preferred version for the creation of new DB clusters, including restores from snapshots.

This is not a mandatory upgrade for existing clusters. You will have the option to upgrade existing clusters to version 1.12 after we complete the fleet-wide patch to 1.11 (see Aurora 1.11 [release notes](AuroraMySQL.Updates.20170223.md) and corresponding [forum announcement](https://forums.aws.amazon.com/ann.jspa?annID=4444)). With version 1.12 of Aurora, we are using a cluster patching model where all nodes in an Aurora DB cluster are patched at the same time. For more information, see [ Maintaining an Amazon Aurora DB cluster](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/USER_UpgradeDBInstance.Maintenance.html) in the *Amazon Aurora User Guide*.

## New features

+ **Fast DDL** – Aurora MySQL now allows you to execute an ALTER TABLE *tbl\$1name* ADD COLUMN *col\$1name* *column\$1definition* operation nearly instantaneously. The operation completes without requiring the table to be copied and without materially impacting other DML statements. Since it does not consume temporary storage for a table copy, it makes DDL statements practical even for large tables on small instance classes. Fast DDL is currently only supported for adding a nullable column, without a default value, at the end of a table. This feature is currently available in Aurora lab mode. For more information, see [ Altering tables in Amazon Aurora using fast DDL](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Managing.FastDDL.html) in the *Amazon Aurora User Guide*.
+ **Show volume status** – We have added a new monitoring command, SHOW VOLUME STATUS, to display the number of nodes and disks in a volume. For more information, see [ Displaying volume status for an Aurora MySQL DB cluster](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Managing.VolumeStatus.html) in the *Amazon Aurora User Guide*.

## Improvements

+ Implemented changes to lock compression to further reduce memory allocated per lock object. This improvement is available in lab mode.
+ Fixed an issue where the `trx_active_transactions` metric decrements rapidly even when the database is idle.
+ Fixed an invalid error message regarding fault injection query syntax when simulating failure in disks and nodes.
+ Fixed multiple issues related to race conditions and dead latches in the lock manager.
+ Fixed an issue causing a buffer overflow in the query optimizer.
+ Fixed a stability issue in Aurora read replicas when the underlying storage nodes experience low available memory.
+ Fixed an issue where idle connections persisted past the `wait_timeout` parameter setting.
+ Fixed an issue where `query_cache_size` returns an unexpected value after reboot of the instance.
+ Fixed a performance issue that is the result of a diagnostic thread probing the network too often in the event that writes are not progressing to storage.

## Integration of MySQL bug fixes

+ Reloading a table that was evicted while empty caused an AUTO\$1INCREMENT value to be reset. (Bug \$121454472, Bug \$177743)
+ An index record was not found on rollback due to inconsistencies in the purge\$1node\$1t structure. The inconsistency resulted in warnings and error messages such as "error in sec index entry update", "unable to purge a record", and "tried to purge sec index entry not marked for deletion". (Bug \$119138298, Bug \$170214, Bug \$121126772, Bug \$121065746) 
+ Wrong stack size calculation for qsort operation leads to stack overflow. (Bug \$173979)
+ Record not found in an index upon rollback. (Bug \$170214, Bug \$172419)
+ ALTER TABLE add column TIMESTAMP on update CURRENT\$1TIMESTAMP inserts ZERO-datas (Bug \$117392)