DorisDataTableScan.java

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//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.iceberg;

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ExecutorService;
import java.util.function.Function;

/** Keeps partition pruning aligned with the schema selected by the Doris relation. */
public class DorisDataTableScan extends DataTableScan {
    private DorisDataTableScan(Table table, Schema schema, TableScanContext context) {
        super(table, schema, context);
    }

    public static TableScan wrap(TableScan scan) {
        if (!(scan instanceof DataTableScan)) {
            return scan;
        }
        DataTableScan dataScan = (DataTableScan) scan;
        return new DorisDataTableScan(dataScan.table(), dataScan.tableSchema(), dataScan.context());
    }

    /**
     * Rebinds native manifest planning to a query-local table, preserving the complete scan context.
     * Custom tables/scans may implement different planning semantics and must keep their original behavior.
     */
    public static Optional<TableScan> withPlanningTable(TableScan scan, Function<Table, Optional<Table>> tableView,
            ExecutorService executor) {
        if (scan.getClass() != DataTableScan.class && scan.getClass() != DorisDataTableScan.class) {
            return Optional.empty();
        }
        Optional<Table> view = tableView.apply(scan.table());
        if (!view.isPresent()) {
            return Optional.empty();
        }
        DataTableScan nativeScan = (DataTableScan) scan;
        // schema() may be a projection excluding predicate columns. Keep the original binding schema too.
        TableScan scoped = scan.getClass() == DorisDataTableScan.class
                ? new DorisDataTableScan(view.get(), nativeScan.tableSchema(), nativeScan.context())
                : new DataTableScan(view.get(), nativeScan.tableSchema(), nativeScan.context());
        // An explicit planWith would override the SDK's plan-in-worker-pool=false setting.
        return Optional.of(nativeScan.shouldPlanWithExecutor() ? scoped.planWith(executor) : scoped);
    }

    /** Rebinds snapshot specs by field ID to the full schema selected for the scan. */
    public static Map<Integer, PartitionSpec> specsForScan(TableScan scan) {
        Map<Integer, PartitionSpec> tableSpecs = scan.table().specs();
        Schema schema = scan.schema();
        if (tableSpecs.values().stream().allMatch(spec -> spec.schema() == schema)) {
            return tableSpecs;
        }
        Map<Integer, PartitionSpec> specs = new HashMap<>();
        // A schema-only update keeps the snapshot ID unchanged. Snapshot IDs therefore cannot
        // determine whether table specs still use the schema selected by a historical query.
        Snapshot snapshot = scan.snapshot();
        if (snapshot != null) {
            // Later, unused specs can have partition names that conflict with historical columns.
            // Bind only specs referenced by this snapshot, including those needed for delete files.
            for (ManifestFile manifest : snapshot.allManifests(scan.table().io())) {
                int specId = manifest.partitionSpecId();
                specs.computeIfAbsent(specId, id -> {
                    PartitionSpec spec = tableSpecs.get(id);
                    return spec.schema() == schema ? spec : spec.toUnbound().bind(schema, true);
                });
            }
        }
        return specs;
    }

    @Override
    protected Map<Integer, PartitionSpec> specs() {
        return specsForScan(this);
    }

    @Override
    protected TableScan newRefinedScan(Table table, Schema schema, TableScanContext context) {
        return new DorisDataTableScan(table, schema, context);
    }
}