* Removing unused code from io.druid.java.util.common.guava package; fix#3563 (more consistent and paranoiac resource handing in Sequences subsystem); Add Sequences.wrap() for DRY in MetricsEmittingQueryRunner, CPUTimeMetricQueryRunner and SpecificSegmentQueryRunner; Catch MissingSegmentsException in SpecificSegmentQueryRunner's yielder.next() method (follow up on #3617)
* Make Sequences.withEffect() execute the effect if the wrapped sequence throws exception from close()
* Fix strange code in MetricsEmittingQueryRunner
* Add comment on why YieldingSequenceBase is used in Sequences.withEffect()
* Use Closer in OrderedMergeSequence and MergeSequence to close multiple yielders
* SQL: Ditch CalciteConnection layer and add DruidMeta, extension aggregators.
Switched from CalciteConnection to Planner, bringing benefits:
- CalciteConnection's JDBC interface no longer sits between the SQL server
(HTTP/Avatica) and Druid's query layer. Instead, the SQL servers can use
Druid Sequence objects directly, reducing overhead in the query return path.
- Implemented our own Planner-based Avatica Meta, letting us control
connection timeouts and connection / statement limits. The previous
CalciteConnection-based implementation didn't have any limits or timeouts.
- The Planner interface lets us override the operator table, opening up
SQL language extensions. This patch includes two: APPROX_COUNT_DISTINCT
in core, and a QUANTILE aggregator in the druid-histogram extension.
Also:
- Added INFORMATION_SCHEMA metadata schema.
- Added tests for Unicode literals and escapes.
* Verify statement is actually open before closing it.
* More detailed INFORMATION_SCHEMA docs.
* Fix#3795 (Java 7 compatibility).
Also introduce Animal Sniffer checks during build, which would
have caught the original problems.
* Add Animal Sniffer on caffeine-cache for JDK8.
Excludes tests from AvoidStaticImport, since those are used often there and
I didn't want to make this changeset too large. Production code use was minimal
and I switched those to non-static imports.
Gian Merlino
Roman Leventov
Himanshu
Akash Dwivedi
Navis Ryu
Parag Jain
Charles Allen