# Presto 316 Documentation

## 12.3. Release 314

## General Changes

- Fix incorrect results for `BETWEEN` involving `NULL` values. (#877)
- Fix query history leak in coordinator. (#939, #944)
- Fix idle client timeout handling. (#947)
- Improve performance of `json_parse()` function. (#904)
- Visualize plan structure in `EXPLAIN` output. (#888)
- Add support for positional access to `ROW` fields via the subscript operator. (#860)

## CLI Changes

- Add JSON output format. (#878)

## Web UI Changes

- Fix queued queries counter in UI. (#894)

## Server RPM Changes

- Change default location of the `http-request.log` to `/var/log/presto`. Previously, the log would be located in `/var/lib/presto/data/var/log` by default. (#919)

## Hive Connector Changes

- Fix listing tables and views from Hive 2.3+ Metastore on certain databases, including Derby and Oracle. This fixes `SHOW TABLES`, `SHOW VIEWS` and reading from `information_schema.tables` table. (#833)
- Fix handling of Avro tables with `avro.schema.url` defined in Hive `SERDEPROPERTIES`. (#898)
- Fix regression that caused ORC bloom filters to be ignored. (#921)
- Add support for reading LZ4 and ZSTD compressed Parquet data. (#910)
- Add support for writing ZSTD compressed ORC data. (#910)
- Add support for configuring ZSTD and LZ4 as default compression methods via the `hive.compression-codec` configuration option. (#910)
- Do not allow inserting into text format tables that have a header or footer. (#891)
- Add `textfile_skip_header_line_count` and `textfile_skip_footer_line_count` table properties for text format tables that specify the number of header and footer lines. (#845)
- Add `hive.max-splits-per-second` configuration property to allow throttling the split discovery rate, which can reduce load on the file system. (#534)
- Support overwriting unpartitioned tables for insert queries. (#924)

## PostgreSQL Connector Changes

- Support PostgreSQL arrays declared using internal type name, for example `_int4` (rather than `int[]`). (#659)

## Elasticsearch Connector Changes

- Add support for mixed-case field names. (#887)

## Base-JDBC Connector Library Changes

- Allow connectors to customize how they store `NULL` values. (#918)

## SPI Changes

- Expose the SQL text of the executed prepared statement to `EventListener`. (#908)
- Deprecate table layouts for `ConnectorMetadata.makeCompatiblePartitioning()`. (#689)
- Add support for delete pushdown into connectors via the `ConnectorMetadata.applyDelete()` and `ConnectorMetadata.executeDelete()` methods. (#689)
- Allow connectors without distributed tables. (#893)