12.65. Release 0.181
General Changes
- Fix query failure and memory usage tracking when query contains
transform_keys() or transform_values().
- Prevent
CREATE TABLE IF NOT EXISTS queries from ever failing with “Table already exists”.
- Fix query failure when
ORDER BY expressions reference columns that are used in
the GROUP BY clause by their fully-qualified name.
- Fix excessive GC overhead caused by large arrays and maps containing
VARCHAR elements.
- Improve error handling when passing too many arguments to various
functions or operators that take a variable number of arguments.
- Improve performance of
count(*) aggregations over subqueries with known
constant cardinality.
- Add
VERBOSE option for EXPLAIN ANALYZE that provides additional
low-level details about query performance.
- Add per-task distribution information to the output of
EXPLAIN ANALYZE.
- Add support for
DROP COLUMN in ALTER TABLE.
- Change local scheduler to prevent starvation of long running queries
when the cluster is under constant load from short queries. The new
behavior is disabled by default and can be enabled by setting the
config property
task.level-absolute-priority=true.
- Improve the fairness of the local scheduler such that long-running queries
which spend more time on the CPU per scheduling quanta (e.g., due to
slow connectors) do not get a disproportionate share of CPU. The new
behavior is disabled by default and can be enabled by setting the
config property
task.legacy-scheduling-behavior=false.
- Add a config option to control the prioritization of queries based on
elapsed scheduled time. The
task.level-time-multiplier property
controls the target scheduled time of a level relative to the next
level. Higher values for this property increase the fraction of CPU
that will be allocated to shorter queries. This config property only
has an effect when task.level-absolute-priority=true and
task.legacy-scheduling-behavior=false.
Hive Changes
- Fix potential native memory leak when writing tables using RCFile.
- Correctly categorize certain errors when writing tables using RCFile.
- Decrease the number of file system metadata calls when reading tables.
- Add support for dropping columns.
JDBC Driver Changes
- Add support for query cancellation using
Statement.cancel().
PostgreSQL Changes
- Add support for operations on external tables.
Accumulo Changes
- Improve query performance by scanning index ranges in parallel.
SPI Changes
- Fix regression that broke serialization for
SchemaTableName.
- Add access control check for
DROP COLUMN.
