# Presto 316 Documentation

## 12.68. Release 0.165

## General Changes

- Make `AT` a non-reserved keyword.
- Improve performance of `transform()`.
- Improve exchange performance by deserializing in parallel.
- Add support for compressed exchanges. This can be enabled with the `exchange.compression-enabled` config option.
- Add input and hash collision statistics to EXPLAIN ANALYZE output.

## Hive Changes

- Add support for MAP and ARRAY types in optimized Parquet reader.

## MySQL and PostgreSQL Changes

- Fix connection leak on workers.