# Presto 316 Documentation

## 12.23. Release 0.210

## General Changes

- Fix planning failure when aliasing columns of tables containing hidden columns (#11385).
- Fix correctness issue when `GROUP BY DISTINCT` terms contain references to the same column using different syntactic forms (#11120).
- Fix failures when querying `information_schema` tables using capitalized names.
- Improve performance when converting between `ROW` types.
- Remove user CPU time tracking as introduces non-trivial overhead.
- Select join distribution type automatically for queries involving outer joins.

## Hive Connector Changes

- Fix a security bug introduced in 0.209 when using `hive.security=file`, which would allow any user to create, drop, or rename schemas.
- Prevent ORC writer from writing stripes larger than the max configured size when converting a highly dictionary compressed column to direct encoding.
- Support creating Avro tables with a custom schema using the `avro_schema_url` table property.
- Support backward compatible Avro schema evolution.
- Support cross-realm Kerberos authentication for HDFS and Hive Metastore.

## JDBC Driver Changes

- Deallocate prepared statement when `PreparedStatement` is closed. Previously, `Connection` became unusable after many prepared statements were created.
- Remove `getUserTimeMillis()` from `QueryStats` and `StageStats`.

## SPI Changes

- `SystemAccessControl.checkCanSetUser()` now takes an `Optional<Principal>` rather than a nullable `Principal`.
- Rename `connectorId` to `catalogName` in `ConnectorFactory`, `QueryInputMetadata`, and `QueryOutputMetadata`.
- Pass `ConnectorTransactionHandle` to `ConnectorAccessControl.checkCanSetCatalogSessionProperty()`.
- Remove `getUserTime()` from `SplitStatistics` (referenced in `SplitCompletedEvent`).

Note

These are backwards incompatible changes with the previous SPI. If you have written a plugin, you will need to update your code before deploying this release.