drill

2a9e51f8 - DRILL-6381: (Part 4) Enhance MapR-DB plugin to support querying secondary indexes

DRILL-6381: (Part 4) Enhance MapR-DB plugin to support querying secondary indexes   1. Implementation of the index descriptor for MapR-DB. 2. MapR-DB specific costing for covering and non-covering indexes. 3. Discovery componenent to discover the indexes available for a MapR-DB table including CAST functional indexes. 4. Utility functions to build a canonical index descriptor. 5. Statistics: fetch and initialize statistcs from MapR-DB for a query condition. Maintain a query-scoped cache for the statistics. Utility functions to compute selectivity. 6. Range Partitioning: partitioning function that takes into account the tablet map to find out where a particular rowkey belongs. 7. Restricted Scan: support doing restricted (i.e skip) scan through lookups on the rowkey. Added a group-scan and record reader for this. 8. MD-3726: Simple Order by queries (without limit) when an index is used are showing regression. 9. MD-3995: Do not pushdown limit 0 past project with CONVERT_FROMJSON 10. MD-4259 : Account for limit during hashcode computation Co-authored-by: Aman Sinha <asinha@maprtech.com> Co-authored-by: chunhui-shi <cshi@maprtech.com> Co-authored-by: Gautam Parai <gparai@maprtech.com> Co-authored-by: Padma Penumarthy <ppenumar97@yahoo.com> Co-authored-by: Hanumath Rao Maduri <hmaduri@maprtech.com> Conflicts: contrib/format-maprdb/src/main/java/org/apache/drill/exec/store/mapr/db/MapRDBFormatMatcher.java contrib/format-maprdb/src/main/java/org/apache/drill/exec/store/mapr/db/MapRDBPushProjectIntoScan.java contrib/format-maprdb/src/main/java/org/apache/drill/exec/store/mapr/db/json/JsonTableGroupScan.java exec/java-exec/src/main/java/org/apache/drill/exec/planner/index/rules/DbScanSortRemovalRule.java exec/java-exec/src/main/java/org/apache/drill/exec/planner/physical/SortPrel.java exec/java-exec/src/main/java/org/apache/drill/exec/planner/physical/TopNPrel.java Fix additional compilation issues.