protected void doMatch(
RelOptRuleCall call, ScanPrel scan, ProjectPrel project, FilterPrel filter) {
final RexNode condition = filter.getCondition();
InfoSchemaGroupScan groupScan = (InfoSchemaGroupScan) scan.getGroupScan();
if (groupScan.isFilterPushedDown()) {
return;
}
LogicalExpression conditionExp =
DrillOptiq.toDrill(
new DrillParseContext(PrelUtil.getPlannerSettings(call.getPlanner())),
project != null ? project : scan,
condition);
InfoSchemaFilterBuilder filterBuilder = new InfoSchemaFilterBuilder(conditionExp);
InfoSchemaFilter infoSchemaFilter = filterBuilder.build();
if (infoSchemaFilter == null) {
return; // no filter pushdown ==> No transformation.
}
final InfoSchemaGroupScan newGroupsScan =
new InfoSchemaGroupScan(groupScan.getTable(), infoSchemaFilter);
newGroupsScan.setFilterPushedDown(true);
RelNode input = ScanPrel.create(scan, filter.getTraitSet(), newGroupsScan, scan.getRowType());
if (project != null) {
input =
project.copy(project.getTraitSet(), input, project.getProjects(), filter.getRowType());
}
if (filterBuilder.isAllExpressionsConverted()) {
// Filter can be removed as all expressions in the filter are converted and pushed to scan
call.transformTo(input);
} else {
call.transformTo(filter.copy(filter.getTraitSet(), ImmutableList.of(input)));
}
}
@Override
public boolean matches(RelOptRuleCall call) {
final ScanPrel scan = (ScanPrel) call.rel(1);
GroupScan groupScan = scan.getGroupScan();
return groupScan instanceof InfoSchemaGroupScan;
}