DRILL-1488: Provide configurable option to set the sql identifier max length which is passed to Calcite's SQL parser. Main fix is in Calcite version 0.9-drill-r9 (see CALCITE-464).
DRILL-1780: check if result set is empty before accessing;
 show a neat message to the user when resultset is empty; minor refactorings
 to DrillRestServer
DRILL-1641: Fix failure of kvgen(...) on indexed repeated map.