# Presto 316 Documentation

## 12.75. Release 0.158

## General Changes

- Fix regression that could cause high CPU and heap usage on coordinator when processing certain types of long running queries.
- Fix incorrect pruning of output columns in `EXPLAIN ANALYZE`.
- Fix ordering of `CHAR` values so that trailing spaces are ordered after control characters.
- Fix query failures for connectors that produce non-remotely accessible splits.
- Fix non-linear performance issue when parsing certain SQL expressions.
- Fix case-sensitivity issues when operating on columns of `ROW` data type.
- Fix failure when creating views for tables names that need quoting.
- Return `NULL` from `element_at()` for out-of-range indices instead of failing.
- Remove redundancies in query plans, which can reduce data transfers over the network and reduce CPU requirements.
- Validate resource groups configuration file on startup to ensure that all selectors reference a configured resource group.
- Add experimental on-disk merge sort for aggregations. This can be enabled with the `experimental.spill-enabled` configuration flag.
- Push down predicates for `DECIMAL`, `TINYINT`, `SMALLINT` and `REAL` data types.

## Hive Changes

- Add hidden `$bucket` column for bucketed tables that contains the bucket number for the current row.
- Prevent inserting into non-managed (i.e., external) tables.
- Add configurable size limit to Hive metastore cache to avoid using too much coordinator memory.

## Cassandra Changes

- Allow starting the server even if a contact point hostname cannot be resolved.