* Expressions: Add ExprMacros, which have the same syntax as functions, but
can convert themselves to any kind of Expr at parse-time.
ExprMacroTable is an extension point for adding new ExprMacros. Anything
that might need to parse expressions needs an ExprMacroTable, which can
be injected through Guice.
* Address code review comments.
* 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.
* Eliminate exclusion groups from pull-deps
* Only consider dependency nodes in pull-deps if they are not in the following scopes
* provided
* test
* system
* Fix a bunch of `<scope>provided</scope>` missing tags
* Better exclusions for a couple of problematic libs
Roman Leventov
Gian Merlino
Nishant
fjy