12.28. Release 0.208
Warning
This release has the potential for data loss in the Hive connectorwhen writing bucketed sorted tables.
General Changes
- Fix an issue with memory accounting that would lead to garbage collection pausesand out of memory exceptions.
- Fix an issue that produces incorrect results when
push_aggregation_through_join
is enabled (#10724). - Preserve field names when unnesting columns of type
ROW
. - Make the cluster out of memory killer more resilient to memory accounting leaks.Previously, memory accounting leaks on the workers could effectively disablethe out of memory killer.
- Improve planning time for queries over tables with high column count.
- Add a limit on the number of stages in a query. The default is
100
and canbe changed with thequery.max-stage-count
configuration property and thequery_max_stage_count
session property. - Add
spooky_hash_v2_32()
andspooky_hash_v2_64()
functions. - Add a cluster memory leak detector that logs queries that have possibly accounted formemory usage incorrectly on workers. This is a tool to for debugging internal errors.
- Add support for correlated subqueries requiring coercions.
- Add experimental support for running on Linux ppc64le.
CLI Changes
- Fix creation of the history file when it does not exist.
- Add
PRESTO_HISTORY_FILE
environment variable to override location of history file.
Hive Connector Changes
- Remove size limit for writing bucketed sorted tables.
- Support writer scaling for Parquet.
- Improve stripe size estimation for the optimized ORC writer. This reduces thenumber of cases where tiny ORC stripes will be written.
- Provide the actual size of CHAR, VARCHAR, and VARBINARY columns to the cost based optimizer.
- Collect column level statistics when writing tables. This is disabled by default,and can be enabled by setting the
hive.collect-column-statistics-on-write
property.
Thrift Connector Changes
- Include error message from remote server in query failure message.