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 GROUPINGSETS, 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.
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.
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.