rdblue commented on a change in pull request #695: [WIP] Cherrypick snapshot feature URL: https://github.com/apache/incubator-iceberg/pull/695#discussion_r358946689
########## File path: core/src/main/java/org/apache/iceberg/CherryPickFromSnapshot.java ########## @@ -0,0 +1,136 @@ +/* + * 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; + +import com.google.common.base.Preconditions; +import org.apache.iceberg.exceptions.CommitFailedException; +import org.apache.iceberg.exceptions.ValidationException; + +/** + * In an audit workflow, new data is written to an orphan snapshot that is not committed as the table's + * current state until it is audited. After auditing a change, it may need to be applied or cherry-picked + * on top of the latest snapshot instead of the one that was current when the audited changes were created. + * + * This class adds support for cherry-picking the changes from an orphan snapshot by applying them to + * the current snapshot. The output of the operation is a new snapshot with the changes from cherry-picked + * snapshot. + * + * Cherry-picking should apply the exact set of changes that were done in the original commit. + * - All added files should be added to the new version. + * - Todo: If files were deleted, then those files must still exist in the data set. + * - Does not support Overwrite operations currently. Overwrites are considered as conflicts. + * + */ +class CherryPickFromSnapshot extends MergingSnapshotProducer<CherryPick> implements CherryPick { + private final TableOperations ops; + private TableMetadata base; + private Long cherryPickSnapshotId = null; + + CherryPickFromSnapshot(TableOperations ops) { + super(ops); + this.ops = ops; + this.base = ops.refresh(); + } + + @Override + protected CherryPick self() { + return this; + } + + /** + * We only cherry pick for appends right now + * @return + */ + @Override + protected String operation() { + Snapshot cherryPickSnapshot = base.snapshot(cherryPickSnapshotId); + return cherryPickSnapshot.operation(); + } + + @Override + public CherryPickFromSnapshot cherrypick(long snapshotId) { + Preconditions.checkArgument(base.snapshot(snapshotId) != null, + "Cannot cherry pick unknown snapshot id: %s", snapshotId); + + this.cherryPickSnapshotId = snapshotId; + return this; + } + + /** + * Apply the pending changes and return the uncommitted changes for validation. + * <p> + * This does not result in a permanent update. + * + * @return the uncommitted changes that would be committed by calling {@link #commit()} + * @throws ValidationException If the pending changes cannot be applied to the current metadata + * @throws IllegalArgumentException If the pending changes are conflicting or invalid + */ + @Override + public Snapshot apply() { + ValidationException.check(cherryPickSnapshotId != null, + "Cannot cherry pick unknown version: call cherrypick"); + + Snapshot cherryPickSnapshot = base.snapshot(cherryPickSnapshotId); + String wapId = stagedWapId(cherryPickSnapshot); + ValidationException.check(!base.isWapIdPublished(Long.parseLong(wapId)), + "Duplicate request to cherry pick wap id that was published already: %s", wapId); + + // only append operations are currently supported + if (!cherryPickSnapshot.operation().equals(DataOperations.APPEND)) { + throw new UnsupportedOperationException("Can cherry pick only append operations"); + } + + // Todo: + // - Check if files to be deleted exist in current snapshot, + // ignore those files or reject incoming snapshot entirely? + // - Check if there are overwrites, ignore those files or reject incoming snapshot entirely? + + for (DataFile addedFile : cherryPickSnapshot.addedFiles()) { + add(addedFile); + } + set(SnapshotSummary.PUBLISHED_WAP_ID_PROP, wapId); + Snapshot outputSnapshot = super.apply(); + TableMetadata updated = base.addStagedSnapshot(outputSnapshot); + ops.commit(base, updated); Review comment: The commit should not be done in the apply method. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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