* Move scan-query from a contrib extension into core.
Based on a proposal at: https://groups.google.com/d/topic/druid-development/ME_OatUDnbk/discussion
This patch also adds support for virtual columns to the Scan query,
and updates Druid SQL to use Scan instead of Select.
This patch also makes some behavioral changes to handling of the __time
column. In particular, it is now is returned as "__time" rather than
"timestamp"; it is no longer included if you do not specifically ask for
it in your "columns"; and it is returned as a long rather than a string.
Users can revert time handling to the legacy extension behavior by
setting "legacy" : true in their queries, or setting the property
druid.query.scan.legacy = true. This is meant to provide a migration
path for users that were formerly using the contrib extension.
* Adjustments from review.
* Add back Select query.
* Adjust SQL docs.
* Restore SelectQuery link.
* Add numeric StringComparator
* Only use direct long comparison for numeric ordering in BoundFilter, add time filtering benchmark query
* Address PR comments, add multithreaded BoundDimFilter test
* Add comment on strlen tie handling
* Add timeseries interval filter benchmark
* Adjust docs
* Use jackson for StringComparator, address PR comments
* Add new TopNMetricSpec and SearchSortSpec with tests (WIP)
* More TopNMetricSpec and SearchSortSpec tests
* Fix NewSearchSortSpec serde
* Update docs for new DimensionTopNMetricSpec
* Delete NumericDimensionTopNMetricSpec
* Delete old SearchSortSpec
* Rename NewSearchSortSpec to SearchSortSpec
* Add TopN numeric comparator benchmark, address PR comments
* Refactor OrderByColumnSpec
* Add null checks to NumericComparator and String->BigDecimal conversion function
* Add more OrderByColumnSpec serde tests
- Add central doc for multi-value dimensions, with some content from other docs.
- Link to multi-value dimension doc from topN and groupBy docs.
- Fixes a broken link from dimensionspecs.md, which was presciently already
linking to this nonexistent doc.
- Resolve inconsistent naming in docs & code (sometimes "multi-valued", sometimes
"multi-value") in favor of "multi-value".
Gian Merlino
Parag Jain
Aseem Bansal
Jonathan Wei
Fangjin Yang
David Lim
Xavier Léauté