SourabhBadhya commented on code in PR #4032: URL: https://github.com/apache/hive/pull/4032#discussion_r1108051403
########## ql/src/java/org/apache/hadoop/hive/ql/txn/compactor/handler/Handler.java: ########## @@ -0,0 +1,179 @@ +/* + * 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.hadoop.hive.ql.txn.compactor.handler; + +import com.google.common.cache.Cache; +import com.google.common.cache.CacheBuilder; +import org.apache.hadoop.fs.Path; +import org.apache.hadoop.hive.conf.HiveConf; +import org.apache.hadoop.hive.metastore.api.MetaException; +import org.apache.hadoop.hive.metastore.api.Partition; +import org.apache.hadoop.hive.metastore.api.Table; +import org.apache.hadoop.hive.metastore.conf.MetastoreConf; +import org.apache.hadoop.hive.metastore.txn.TxnStore; +import org.apache.hadoop.hive.ql.io.AcidDirectory; +import org.apache.hadoop.hive.ql.txn.compactor.CleaningRequest; +import org.apache.hadoop.hive.ql.txn.compactor.CompactorUtil; +import org.apache.thrift.TBase; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.Arrays; +import java.util.List; +import java.util.Optional; +import java.util.concurrent.Callable; +import java.util.concurrent.ExecutionException; + +import static org.apache.hadoop.hive.metastore.HMSHandler.getMSForConf; +import static org.apache.hadoop.hive.metastore.utils.MetaStoreUtils.getDefaultCatalog; + +/** + * An abstract class which defines the list of utility methods for performing cleanup activities. + */ +public abstract class Handler<T extends CleaningRequest> { + + private static final Logger LOG = LoggerFactory.getLogger(Handler.class.getName()); + protected final TxnStore txnHandler; + protected final HiveConf conf; + protected final boolean metricsEnabled; + private Optional<Cache<String, TBase>> metaCache; + + Handler(HiveConf conf, TxnStore txnHandler, boolean metricsEnabled) { + this.conf = conf; + this.txnHandler = txnHandler; + boolean tableCacheOn = MetastoreConf.getBoolVar(this.conf, MetastoreConf.ConfVars.COMPACTOR_CLEANER_TABLECACHE_ON); + this.metaCache = initializeCache(tableCacheOn); + this.metricsEnabled = metricsEnabled; + } + + public HiveConf getConf() { + return conf; + } + + public TxnStore getTxnHandler() { + return txnHandler; + } + + public boolean isMetricsEnabled() { + return metricsEnabled; + } + + /** + * Find the list of objects which are ready for cleaning. + * @return Cleaning requests + */ + public abstract List<T> findReadyToClean() throws MetaException; + + /** + * Execute just before cleanup + * @param cleaningRequest - Cleaning request + */ + public abstract void beforeExecutingCleaningRequest(T cleaningRequest) throws MetaException; + + /** + * Execute just after cleanup + * @param cleaningRequest Cleaning request + * @param deletedFiles List of deleted files + * @return True if cleanup was successful, false otherwise + * @throws MetaException + */ + public abstract boolean afterExecutingCleaningRequest(T cleaningRequest, List<Path> deletedFiles) throws MetaException; + + /** + * Execute in the event of failure + * @param cleaningRequest Cleaning request + * @param ex Failure exception + * @throws MetaException + */ + public abstract void failureExecutingCleaningRequest(T cleaningRequest, Exception ex) throws MetaException; + + public Table resolveTable(String dbName, String tableName) throws MetaException { + try { + return getMSForConf(conf).getTable(getDefaultCatalog(conf), dbName, tableName); + } catch (MetaException e) { + LOG.error("Unable to find table {}.{}, {}", dbName, tableName, e.getMessage()); + throw e; + } + } + + protected Partition resolvePartition(String dbName, String tableName, String partName) throws MetaException { + if (partName != null) { + List<Partition> parts; + try { + parts = CompactorUtil.getPartitionsByNames(conf, dbName, tableName, partName); + if (parts == null || parts.isEmpty()) { + // The partition got dropped before we went looking for it. + return null; + } + } catch (Exception e) { + LOG.error("Unable to find partition: {}.{}.{}", dbName, tableName, partName, e); + throw e; + } + if (parts.size() != 1) { + LOG.error("{}.{}.{} does not refer to a single partition. {}", dbName, tableName, partName, + Arrays.toString(parts.toArray())); + throw new MetaException(String.join("Too many partitions for : ", dbName, tableName, partName)); + } + return parts.get(0); + } else { + return null; + } + } + + public <B extends TBase<B,?>> B computeIfAbsent(String key, Callable<B> callable) throws Exception { + if (metaCache.isPresent()) { + try { + return (B) metaCache.get().get(key, callable); + } catch (ExecutionException e) { + throw (Exception) e.getCause(); + } + } + return callable.call(); + } + + Optional<Cache<String, TBase>> initializeCache(boolean tableCacheOn) { + if (tableCacheOn) { + metaCache = Optional.of(CacheBuilder.newBuilder().softValues().build()); + } + return metaCache; + } + + public void invalidateMetaCache() { + metaCache.ifPresent(Cache::invalidateAll); + } + + protected List<Path> getObsoleteDirs(AcidDirectory dir, boolean isDynPartAbort) { + List<Path> obsoleteDirs = dir.getObsolete(); + /* + * add anything in 'dir' that only has data from aborted transactions - no one should be + * trying to read anything in that dir (except getAcidState() that only reads the name of + * this dir itself) + * So this may run ahead of {@link CompactionInfo#highestWriteId} but it's ok (suppose there + * are no active txns when cleaner runs). The key is to not delete metadata about aborted + * txns with write IDs > {@link CompactionInfo#highestWriteId}. + * See {@link TxnStore#markCleaned(CompactionInfo)} + */ + obsoleteDirs.addAll(dir.getAbortedDirectories()); + if (isDynPartAbort) { + // In the event of an aborted DP operation, we should only consider the aborted directories for cleanup. + // Including obsolete directories for partitioned tables can result in data loss. + obsoleteDirs = dir.getAbortedDirectories(); + } + return obsoleteDirs; + } Review Comment: Moved `getObsoleteDirs` to CompactorUtil since its using AcidDirectory which might not be generic to all handlers. However, the caching is done on a handler level now. Hence, caching functions are kept in handlers itself. `resolvePartitions` seems generic to most handlers, hence kept it here. -- 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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