# Presto 316 Documentation

## 12.48. Release 0.185

## General Changes

- Fix incorrect column names in `QueryCompletedEvent`.
- Fix excessive CPU usage in coordinator for queries that have large string literals containing non-ASCII characters.
- Fix potential infinite loop during query optimization when constant expressions fail during evaluation.
- Fix incorrect ordering when the same field appears multiple times with different ordering specifications in a window function `ORDER BY` clause. For example: `OVER (ORDER BY x ASC, x DESC)`.
- Do not allow dropping or renaming hidden columns.
- When preparing to drop a column, ignore hidden columns when checking if the table only has one column.
- Improve performance of joins where the condition is a range over a function. For example: `a JOIN b ON b.x < f(a.x) AND b.x > g(a.x)`
- Improve performance of certain window functions (e.g., `LAG`) with similar specifications.
- Extend `substr()` function to work on `VARBINARY` in addition to `CHAR` and `VARCHAR`.
- Add cast from `JSON` to `ROW`.
- Allow usage of `TRY` within lambda expressions.

## Hive Changes

- Improve ORC reader efficiency by only reading small ORC streams when accessed in the query.
- Improve RCFile IO efficiency by increasing the buffer size from 1 to 8 MB.
- Fix native memory leak for optimized RCFile writer.
- Fix potential native memory leak for optimized ORC writer.

## Memory Connector Changes

- Add support for views.