Presto 0.186 Documentation

11.29. Release 0.158

11.29. 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.