ayushtkn commented on a change in pull request #2043:
URL: https://github.com/apache/hive/pull/2043#discussion_r600579986
##########
File path: ql/src/java/org/apache/hadoop/hive/ql/exec/repl/DirCopyTask.java
##########
@@ -203,4 +213,87 @@ public String getName() {
public boolean canExecuteInParallel() {
return true;
}
+
+ void copyUsingDistCpSnapshots(Path sourcePath, Path targetPath,
+ UserGroupInformation proxyUser) throws IOException {
+
+ DistributedFileSystem sourceFs = SnapshotUtils.getDFS(sourcePath, conf);
+ DistributedFileSystem targetFs = SnapshotUtils.getDFS(targetPath, conf);
+ if (sourceFs == null || targetFs == null) {
+ LOG.error("Source and Destination filesystem are not "
+ + "DistributedFileSystem, using normal copy instead of snapshot "
+ + "copy, Source Path {}, Target Path {}, Source fs is {}, and "
+ + "Target fs {}", sourcePath, targetPath,
+ sourcePath.getFileSystem(conf).getClass(),
+ targetPath.getFileSystem(conf).getClass());
+ FileUtils.distCp(sourcePath.getFileSystem(conf), // source file system
+ Collections.singletonList(sourcePath), // list of source paths
+ targetPath, false, proxyUser, conf, ShimLoader.getHadoopShims());
+ // Since source/dest aren't DFS, no point trying to create snapshot at
+ // target, return from here.
+ return;
+ }
+ String prefix = conf.getVar(
+ HiveConf.ConfVars.REPL_SNAPSHOT_PREFIX_FOR_EXTERNAL_TABLE_COPY);
+ if (getWork().getCopyMode()
+ .equals(SnapshotUtils.SnapshotCopyMode.DIFF_COPY)) {
+ LOG.info("Using snapshot diff copy for source: {} and target: {}",
+ sourcePath, targetPath);
+ boolean result = FileUtils
+ .distCpWithSnapshot(sourceFs, prefix + "old", prefix + "initial",
+ Collections.singletonList(sourcePath), targetPath, proxyUser,
+ conf, ShimLoader.getHadoopShims());
+ if (!result) {
+ LOG.error("Can not copy using snapshot diff for source: {} and "
+ + "target: {}. Falling back to normal copy.", sourcePath,
+ targetPath);
+ FileUtils.distCp(sourcePath.getFileSystem(conf), // source file system
+ Collections.singletonList(sourcePath), // list of source paths
+ targetPath, false, proxyUser, conf, ShimLoader.getHadoopShims());
+ }
+ } else if (getWork().getCopyMode()
+ .equals(SnapshotUtils.SnapshotCopyMode.INITIAL_COPY)) {
+ LOG.info("Using snapshot initial copy for source: {} and target: {}",
+ sourcePath, targetPath);
+ // Try allowSnapshot at target first, if success or already allowed
+ // will use snapshots to copy else fallback.
+ boolean isTargetSnapshottable =
+ SnapshotUtils.allowSnapshot(targetFs, targetPath);
+ if (!isTargetSnapshottable) {
+ // We can not allow creating snapshot at target, so no point moving
+ // to snapshot mode of copy, fallback to normal copy.
+ LOG.error("Can not copy from initial snapshot directory for source: {}
"
+ + "and target: {}. Since target is not snapshottable. Falling "
+ + "back to normal copy.", sourcePath, targetPath);
+ FileUtils.distCp(sourcePath.getFileSystem(conf), // source file system
+ Collections.singletonList(sourcePath), // list of source paths
+ targetPath, false, proxyUser, conf, ShimLoader.getHadoopShims());
+ // Returning to avoid creating snapshots at target.
+ return;
+ } else {
+ // Get the path relative to the initial snapshot for copy.
+ Path snapRelPath = new Path(sourcePath,
+ HdfsConstants.DOT_SNAPSHOT_DIR + "/" + prefix + "initial");
+ boolean result = FileUtils.distCp(sourcePath.getFileSystem(conf), //
+ // source file system
+ Collections.singletonList(snapRelPath), // source path relative to
+ // snapshot
+ targetPath, false, proxyUser, conf, ShimLoader.getHadoopShims());
+ if (!result) {
+ LOG.error(
+ "Can not copy from initial snapshot directory for source: {} "
+ + "and target: {}. Falling back to normal copy.",
snapRelPath,
+ targetPath);
+ FileUtils.distCp(sourcePath.getFileSystem(conf), // source file
system
+ Collections.singletonList(sourcePath), // list of source paths
+ targetPath, false, proxyUser, conf, ShimLoader.getHadoopShims());
+ }
+ }
+ }
+ // Create snapshot at target Filesystem, ignore exceptions if any,
+ // since copy is success, if creation fails, the next iteration shall
+ // handle.
+ SnapshotUtils.deleteSnapshotSafe(targetFs, targetPath, prefix + "old");
Review comment:
added explanation in the comment, Added javadoc to the util method as
well, for posterity
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