# Presto 316 Documentation

## 12.59. Release 0.174

## General Changes

- Fix correctness issue for correlated subqueries containing a `LIMIT` clause.
- Fix query failure when `reduce()` function is used with lambda expressions containing `array_sort()`, `shuffle()`, `reverse()`, `array_intersect()`, `arrays_overlap()`, `concat()` (for arrays) or `map_concat()`.
- Fix a bug that causes underestimation of the amount of memory used by `max_by()`, `min_by()`, `max()`, `min()`, and `arbitrary()` aggregations over varchar/varbinary columns.
- Fix a memory leak in the coordinator that causes long-running queries in highly loaded clusters to consume unnecessary memory.
- Improve performance of aggregate window functions.
- Improve parallelism of queries involving `GROUPING SETS`, `CUBE` or `ROLLUP`.
- Improve parallelism of `UNION` queries.
- Filter and projection operations are now always processed columnar if possible, and Presto will automatically take advantage of dictionary encodings where effective. The `processing_optimization` session property and `optimizer.processing-optimization` configuration option have been removed.
- Add support for escaped unicode sequences in string literals.
- Add SHOW GRANTS and `information_schema.table_privileges` table.

## Hive Changes

- Change default value of `hive.metastore-cache-ttl` and `hive.metastore-refresh-interval` to 0 to disable cross-transaction metadata caching.

## Web UI changes

- Fix ES6 compatibility issue with older browsers.
- Display buffered bytes for every stage in the live plan UI.

## SPI changes

- Add support for retrieving table grants.
- Rename SPI access control check from `checkCanShowTables` to `checkCanShowTablesMetadata`, which is used for both SHOW TABLES and SHOW GRANTS.