PaimonLatestSnapshotProjectionLoader.java

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package org.apache.doris.datasource.metacache.paimon;

import org.apache.doris.catalog.Column;
import org.apache.doris.datasource.CacheException;
import org.apache.doris.datasource.NameMapping;
import org.apache.doris.datasource.paimon.PaimonPartitionInfo;
import org.apache.doris.datasource.paimon.PaimonSchemaCacheValue;
import org.apache.doris.datasource.paimon.PaimonSnapshot;
import org.apache.doris.datasource.paimon.PaimonSnapshotCacheValue;

import org.apache.paimon.CoreOptions;
import org.apache.paimon.Snapshot;
import org.apache.paimon.schema.TableSchema;
import org.apache.paimon.table.DataTable;
import org.apache.paimon.table.Table;

import java.util.Collections;
import java.util.List;
import java.util.Optional;

/**
 * Resolves the latest snapshot runtime projection from the base table entry.
 */
public final class PaimonLatestSnapshotProjectionLoader {
    @FunctionalInterface
    public interface SchemaValueLoader {
        PaimonSchemaCacheValue load(NameMapping nameMapping, long schemaId);
    }

    private final PaimonPartitionInfoLoader partitionInfoLoader;
    private final SchemaValueLoader schemaValueLoader;

    public PaimonLatestSnapshotProjectionLoader(PaimonPartitionInfoLoader partitionInfoLoader,
            SchemaValueLoader schemaValueLoader) {
        this.partitionInfoLoader = partitionInfoLoader;
        this.schemaValueLoader = schemaValueLoader;
    }

    public PaimonSnapshotCacheValue load(NameMapping nameMapping, Table paimonTable) {
        try {
            PaimonSnapshot latestSnapshot = resolveLatestSnapshot(paimonTable);
            List<Column> partitionColumns = schemaValueLoader.load(nameMapping, latestSnapshot.getSchemaId())
                    .getPartitionColumns();
            PaimonPartitionInfo partitionInfo = partitionInfoLoader.load(nameMapping, paimonTable, partitionColumns);
            return new PaimonSnapshotCacheValue(partitionInfo, latestSnapshot);
        } catch (Exception e) {
            throw new CacheException("failed to load paimon snapshot %s.%s.%s: %s",
                    e, nameMapping.getCtlId(), nameMapping.getLocalDbName(), nameMapping.getLocalTblName(),
                    e.getMessage());
        }
    }

    private PaimonSnapshot resolveLatestSnapshot(Table paimonTable) {
        Table snapshotTable = paimonTable;
        long latestSnapshotId = PaimonSnapshot.INVALID_SNAPSHOT_ID;
        Optional<Snapshot> optionalSnapshot = paimonTable.latestSnapshot();
        if (optionalSnapshot.isPresent()) {
            latestSnapshotId = optionalSnapshot.get().id();
            snapshotTable = paimonTable.copy(
                    Collections.singletonMap(CoreOptions.SCAN_SNAPSHOT_ID.key(), String.valueOf(latestSnapshotId)));
        }
        DataTable dataTable = (DataTable) paimonTable;
        long latestSchemaId = dataTable.schemaManager().latest().map(TableSchema::id).orElse(0L);
        return new PaimonSnapshot(latestSnapshotId, latestSchemaId, snapshotTable);
    }
}