shivjha30 commented on code in PR #1495: URL: https://github.com/apache/iceberg/pull/1495#discussion_r1582544488
########## mr/src/main/java/org/apache/iceberg/mr/hive/HiveIcebergMetaHook.java: ########## @@ -0,0 +1,188 @@ +/* + * 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.iceberg.mr.hive; + +import java.util.Properties; +import java.util.Set; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hive.metastore.HiveMetaHook; +import org.apache.hadoop.hive.metastore.api.hive_metastoreConstants; +import org.apache.iceberg.BaseMetastoreTableOperations; +import org.apache.iceberg.CatalogUtil; +import org.apache.iceberg.PartitionSpecParser; +import org.apache.iceberg.Schema; +import org.apache.iceberg.SchemaParser; +import org.apache.iceberg.Table; +import org.apache.iceberg.TableMetadata; +import org.apache.iceberg.TableMetadataParser; +import org.apache.iceberg.TableProperties; +import org.apache.iceberg.catalog.TableIdentifier; +import org.apache.iceberg.exceptions.NoSuchTableException; +import org.apache.iceberg.io.FileIO; +import org.apache.iceberg.mr.Catalogs; +import org.apache.iceberg.mr.InputFormatConfig; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public class HiveIcebergMetaHook implements HiveMetaHook { + private static final Logger LOG = LoggerFactory.getLogger(HiveIcebergMetaHook.class); + private static final Set<String> PARAMETERS_TO_REMOVE = ImmutableSet + .of(InputFormatConfig.TABLE_SCHEMA, InputFormatConfig.PARTITION_SPEC, Catalogs.LOCATION, Catalogs.NAME); + private static final Set<String> PROPERTIES_TO_REMOVE = ImmutableSet + .of(InputFormatConfig.EXTERNAL_TABLE_PURGE, hive_metastoreConstants.META_TABLE_STORAGE, "EXTERNAL", + "bucketing_version"); + + private final Configuration conf; + private Table icebergTable = null; + private Properties catalogProperties; + private boolean deleteIcebergTable; + private FileIO deleteIo; + private TableMetadata deleteMetadata; + + public HiveIcebergMetaHook(Configuration conf) { + this.conf = conf; + } + + @Override + public void preCreateTable(org.apache.hadoop.hive.metastore.api.Table hmsTable) { + this.catalogProperties = getCatalogProperties(hmsTable); + + // Set the table type even for non HiveCatalog based tables + hmsTable.getParameters().put(BaseMetastoreTableOperations.TABLE_TYPE_PROP, + BaseMetastoreTableOperations.ICEBERG_TABLE_TYPE_VALUE.toUpperCase()); + + if (!Catalogs.hiveCatalog(conf)) { + // If not using HiveCatalog check for existing table + try { + this.icebergTable = Catalogs.loadTable(conf, catalogProperties); + + Preconditions.checkArgument(catalogProperties.getProperty(InputFormatConfig.TABLE_SCHEMA) == null, + "Iceberg table already created - can not use provided schema"); + Preconditions.checkArgument(catalogProperties.getProperty(InputFormatConfig.PARTITION_SPEC) == null, + "Iceberg table already created - can not use provided partition specification"); + + LOG.info("Iceberg table already exists {}", icebergTable); + + return; + } catch (NoSuchTableException nte) { + // If the table does not exist we will create it below + } + } + + // If the table does not exist collect data for table creation + String schemaString = catalogProperties.getProperty(InputFormatConfig.TABLE_SCHEMA); + Preconditions.checkNotNull(schemaString, "Please provide a table schema"); + // Just check if it is parsable, and later use for partition specification parsing + Schema schema = SchemaParser.fromJson(schemaString); + + String specString = catalogProperties.getProperty(InputFormatConfig.PARTITION_SPEC); + if (specString != null) { + // Just check if it is parsable + PartitionSpecParser.fromJson(schema, specString); + } + + // Allow purging table data if the table is created now and not set otherwise + if (hmsTable.getParameters().get(InputFormatConfig.EXTERNAL_TABLE_PURGE) == null) { + hmsTable.getParameters().put(InputFormatConfig.EXTERNAL_TABLE_PURGE, "TRUE"); + } + + // Remove creation related properties + PARAMETERS_TO_REMOVE.forEach(hmsTable.getParameters()::remove); + } + + @Override + public void rollbackCreateTable(org.apache.hadoop.hive.metastore.api.Table hmsTable) { + // do nothing + } + + @Override + public void commitCreateTable(org.apache.hadoop.hive.metastore.api.Table hmsTable) { + if (icebergTable == null) { + if (Catalogs.hiveCatalog(conf)) { + catalogProperties.put(TableProperties.ENGINE_HIVE_ENABLED, true); Review Comment: @pvary @rdblue @massdosage In the iceberg documentation i could see that "To enable Hive support globally for an application, set iceberg.engine.hive.enabled=true in its Hadoop configuration." The value of iceberg.engine.hive.enabled must be true in order to enable hive support. However, I could still use Iceberg's hive support even if I set iceberg.engine.hive.enabled to false. If i understand correctly, the value "iceberg.engine.hive.enabled" is irrelevant. Because, if it is a hive catalog we are setting engine.hive.enabled as true. In https://github.com/apache/iceberg/blob/01bc864b8eb8c4ca4240af85f00f4e67c78c466e/hive-metastore/src/main/java/org/apache/iceberg/hive/HiveTableOperations.java#L486 We are initially evaluating the 'engine.hive.enabled' value. In cases where it's a Hive catalog, this value is consistently 'True', rendering the 'iceberg.engine.hive.enabled' as unnecessary. Let me know, if i missed anything in my understanding -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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