Fix null values for DatabaseMetaData.getColumns
Remove SetThreadName as it consumes a significant amount of cpu time
Fix bug in NodeScheduler

HashMap was being recreated on every iteration of loop
Add release notes for 0.61
Revert "Fix bug in NodeScheduler"

This reverts commit 25f921fb81be4d23a68e52634ed763568188df05.

The scheduler changes can result in smaller queries being starved
by bigger queries due to the introduction of global per-node queues.
Reverting for now so we can release. We'll revisit later.
Revert "Remove SetThreadName as it consumes a significant amount of cpu time"

This reverts commit 771756b8b7c302bb679642a8d114053991b95581.

The scheduler changes can result in smaller queries being starved
by bigger queries due to the introduction of global per-node queues.
Reverting for now so we can release. We'll revisit later.
Revert "Global split assignment"

This reverts commit 8cbfd758dd0f09aaee763b9cb41303e4dde6cb9e.

The scheduler changes can result in smaller queries being starved
by bigger queries due to the introduction of global per-node queues.
Reverting for now so we can release. We'll revisit later.
Remove reference to scheduler improvements from release notes
Update Airlift from SNAPSHOT to 0.86
Update to airbase 17

Upgrades maven release plugin to fix an issue when releasing with maven 3.1.1
[maven-release-plugin] prepare release 0.61
[maven-release-plugin] prepare for next development iteration
Use faster implementation of Murmur3 for approx_distinct

Noticeable speedup in approx_distinct benchmarks:

Before:
     sql_approx_count_distinct_long ::  118.746 cpu ms :: in  1.5M,  12.9MB,   12.6M/s,   108MB/s :: out     1,      9B,       8/s,     75B/s
   sql_approx_count_distinct_double ::  119.971 cpu ms :: in  1.5M,  12.9MB,   12.5M/s,   107MB/s :: out     1,      9B,       8/s,     75B/s
sql_approx_count_distinct_varbinary ::  163.847 cpu ms :: in  1.5M,  21.5MB,   9.15M/s,   131MB/s :: out     1,      9B,       6/s,     54B/s

After:
     sql_approx_count_distinct_long ::   32.761 cpu ms :: in  1.5M,  12.9MB,   45.8M/s,   393MB/s :: out     1,      9B,      30/s,    274B/s
   sql_approx_count_distinct_double ::   34.674 cpu ms :: in  1.5M,  12.9MB,   43.3M/s,   371MB/s :: out     1,      9B,      28/s,    259B/s
sql_approx_count_distinct_varbinary ::   79.983 cpu ms :: in  1.5M,  21.5MB,   18.8M/s,   268MB/s :: out     1,      9B,      12/s,    112B/s
Add support for un-decomposable aggregation functions
Add missing @Override annotations
Enable experimental features in dev config
Fix issue when deserializing binary values from Hive

The code was incorrectly getting the raw underlying byte array from BytesWritable
Record "started" counter for queries that fail to parse

In the last release we started tracking parsing failures for error categorization,
but the change was missing the call to increment the started counter.

As a result, the started and completed counters get permanently out of sync
and cause the number of running queries to be reported as 0.
Improve unit tests for approximate aggregations
Add closed form approximate COUNT aggregation