jon-wei commented on code in PR #15469: URL: https://github.com/apache/druid/pull/15469#discussion_r1419729223
########## extensions-core/druid-catalog/src/main/java/org/apache/druid/catalog/sql/LiveCatalogResolver.java: ########## @@ -0,0 +1,211 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.druid.catalog.sql; + +import com.google.common.collect.ImmutableSet; +import org.apache.druid.catalog.model.ColumnSpec; +import org.apache.druid.catalog.model.Columns; +import org.apache.druid.catalog.model.ResolvedTable; +import org.apache.druid.catalog.model.TableId; +import org.apache.druid.catalog.model.facade.DatasourceFacade; +import org.apache.druid.catalog.model.table.DatasourceDefn; +import org.apache.druid.catalog.sync.MetadataCatalog; +import org.apache.druid.query.TableDataSource; +import org.apache.druid.segment.column.ColumnType; +import org.apache.druid.segment.column.RowSignature; +import org.apache.druid.sql.calcite.planner.CatalogResolver; +import org.apache.druid.sql.calcite.table.DatasourceTable; +import org.apache.druid.sql.calcite.table.DatasourceTable.EffectiveColumnMetadata; +import org.apache.druid.sql.calcite.table.DatasourceTable.EffectiveMetadata; +import org.apache.druid.sql.calcite.table.DatasourceTable.PhysicalDatasourceMetadata; +import org.apache.druid.sql.calcite.table.DruidTable; + +import javax.inject.Inject; + +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.Set; + +public class LiveCatalogResolver implements CatalogResolver +{ + private final MetadataCatalog catalog; + + @Inject + public LiveCatalogResolver(final MetadataCatalog catalog) + { + this.catalog = catalog; + } + + private DatasourceFacade datasourceSpec(String name) + { + TableId tableId = TableId.datasource(name); + ResolvedTable table = catalog.resolveTable(tableId); + if (table == null) { + return null; + } + if (!DatasourceDefn.isDatasource(table)) { + return null; + } + return new DatasourceFacade(table); + } + + /** + * Create a {@link DruidTable} based on the physical segments, catalog entry, or both. + */ + @Override + public DruidTable resolveDatasource(String name, PhysicalDatasourceMetadata dsMetadata) + { + DatasourceFacade dsSpec = datasourceSpec(name); + + // No catalog metadata. If there is no physical metadata, then the + // datasource does not exist. Else, if there is physical metadata, the + // datasource is based entirely on the physical information. + if (dsSpec == null) { + return dsMetadata == null ? null : new DatasourceTable(dsMetadata); + } + if (dsMetadata == null) { + // Datasource exists only in the catalog: no physical segments. + return emptyDatasource(name, dsSpec); + } else { + // Datasource exists as both segments and a catalog entry. + return mergeDatasource(dsMetadata, dsSpec); + } + } + + private DruidTable emptyDatasource(String name, DatasourceFacade dsSpec) + { + RowSignature.Builder builder = RowSignature.builder(); + Map<String, EffectiveColumnMetadata> columns = new HashMap<>(); + boolean hasTime = false; + for (ColumnSpec col : dsSpec.columns()) { + EffectiveColumnMetadata colMetadata = columnFromCatalog(col, null); + if (colMetadata.name().equals(Columns.TIME_COLUMN)) { + hasTime = true; + } + builder.add(col.name(), colMetadata.druidType()); + columns.put(col.name(), colMetadata); + } + if (!hasTime) { + columns.put(Columns.TIME_COLUMN, new EffectiveColumnMetadata( + Columns.TIME_COLUMN, + ColumnType.LONG + )); + builder = RowSignature.builder() + .add(Columns.TIME_COLUMN, ColumnType.LONG) + .addAll(builder.build()); + } + + final PhysicalDatasourceMetadata mergedMetadata = new PhysicalDatasourceMetadata( + new TableDataSource(name), + builder.build(), + false, // Cannot join to an empty table + false // Cannot broadcast an empty table + ); + return new DatasourceTable( + mergedMetadata.getRowSignature(), + mergedMetadata, + new EffectiveMetadata(dsSpec, columns, true) + ); + } + + private EffectiveColumnMetadata columnFromCatalog(ColumnSpec col, ColumnType physicalType) + { + ColumnType type = Columns.druidType(col); + if (type != null) { + // Use the type that the user provided. + } else if (physicalType == null) { + // Corner case: the user has defined a column in the catalog, has + // not specified a type (meaning the user wants Druid to decide), but + // there is no data at this moment. Guess String as the type for the + // null values. If new segments appear between now and execution, we'll + // convert the values to string, which is always safe. + type = ColumnType.STRING; + } else { + type = physicalType; + } + return new EffectiveColumnMetadata(col.name(), type); + } + + private DruidTable mergeDatasource( + final PhysicalDatasourceMetadata dsMetadata, + final DatasourceFacade dsSpec) + { + final RowSignature physicalSchema = dsMetadata.getRowSignature(); + Set<String> physicalCols = new HashSet<>(physicalSchema.getColumnNames()); + + // Merge columns. All catalog-defined columns come first, + // in the order defined in the catalog. + final RowSignature.Builder builder = RowSignature.builder(); + Map<String, EffectiveColumnMetadata> columns = new HashMap<>(); + for (ColumnSpec col : dsSpec.columns()) { + ColumnType physicalType = null; + if (physicalCols.remove(col.name())) { + physicalType = dsMetadata.getRowSignature().getColumnType(col.name()).get(); + } + EffectiveColumnMetadata colMetadata = columnFromCatalog(col, physicalType); + builder.add(col.name(), colMetadata.druidType()); + columns.put(col.name(), colMetadata); + } + + // Mark any hidden columns. Assumes that the hidden columns are a disjoint set Review Comment: There isn't enforcement of this right now, as-is if hidden columns overlap with the declared columns, the hiding would be ignored (the user would need to remove the column from the declared set to have the hiding take effect) -- This is an automated message from the Apache Git Service. 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