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Posted to gitbox@hive.apache.org by GitBox <gi...@apache.org> on 2021/11/30 07:43:06 UTC
[GitHub] [hive] ArkoSharma commented on a change in pull request #2539: HIVE-25397: snapshot support for controlled failover
ArkoSharma commented on a change in pull request #2539:
URL: https://github.com/apache/hive/pull/2539#discussion_r759005160
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File path: ql/src/java/org/apache/hadoop/hive/ql/exec/repl/ReplExternalTables.java
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@@ -189,57 +191,137 @@ private void dirLocationToCopy(String tableName, FileList fileList, Path sourceP
targetPath = new Path(Utils.replaceHost(targetPath.toString(), sourcePath.toUri().getHost()));
sourcePath = new Path(Utils.replaceHost(sourcePath.toString(), remoteNS));
}
- fileList.add(new DirCopyWork(tableName, sourcePath, targetPath, copyMode, snapshotPrefix).convertToString());
+ fileList.add(new DirCopyWork(tableName, sourcePath, targetPath, copyMode, snapshotPrefix, isBootstrap).convertToString());
}
- private SnapshotUtils.SnapshotCopyMode createSnapshotsAtSource(Path sourcePath, String snapshotPrefix,
- boolean isSnapshotEnabled, HiveConf conf, SnapshotUtils.ReplSnapshotCount replSnapshotCount, FileList snapPathFileList,
- ArrayList<String> prevSnaps, boolean isBootstrap) throws IOException {
+ SnapshotUtils.SnapshotCopyMode createSnapshotsAtSource(Path sourcePath, Path targetPath, String snapshotPrefix,
+ boolean isSnapshotEnabled, HiveConf conf, SnapshotUtils.ReplSnapshotCount replSnapshotCount, FileList snapPathFileList,
+ ArrayList<String> prevSnaps, boolean isBootstrap) throws IOException {
if (!isSnapshotEnabled) {
LOG.info("Snapshot copy not enabled for path {} Will use normal distCp for copying data.", sourcePath);
return FALLBACK_COPY;
}
DistributedFileSystem sourceDfs = SnapshotUtils.getDFS(sourcePath, conf);
try {
- if(isBootstrap) {
- // Delete any pre existing snapshots.
- SnapshotUtils.deleteSnapshotIfExists(sourceDfs, sourcePath, firstSnapshot(snapshotPrefix), conf);
- SnapshotUtils.deleteSnapshotIfExists(sourceDfs, sourcePath, secondSnapshot(snapshotPrefix), conf);
- allowAndCreateInitialSnapshot(sourcePath, snapshotPrefix, conf, replSnapshotCount, snapPathFileList, sourceDfs);
- return INITIAL_COPY;
+ if(isBootstrap && conf.getBoolVar(HiveConf.ConfVars.REPL_REUSE_SNAPSHOTS)) {
+ try {
+ FileStatus[] listing = sourceDfs.listStatus(new Path(sourcePath, ".snapshot"));
+ for (FileStatus elem : listing) {
+ String snapShotName = elem.getPath().getName();
+ String prefix;
+ if (snapShotName.contains(OLD_SNAPSHOT)) {
+ prefix = snapShotName.substring(0, snapShotName.lastIndexOf(OLD_SNAPSHOT));
+ if(!prefix.equals(snapshotPrefix)) {
+ sourceDfs.renameSnapshot(sourcePath, firstSnapshot(prefix), firstSnapshot(snapshotPrefix));
+ }
+ }
+ if (snapShotName.contains(NEW_SNAPSHOT)) {
+ prefix = snapShotName.substring(0, snapShotName.lastIndexOf(NEW_SNAPSHOT));
+ if(!prefix.equals(snapshotPrefix)) {
+ sourceDfs.renameSnapshot(sourcePath, secondSnapshot(prefix), secondSnapshot(snapshotPrefix));
+ }
+ }
+ }
+ } catch (SnapshotException e) {
+ //dir not snapshottable, continue
+ }
}
+ boolean firstSnapAvailable =
+ SnapshotUtils.isSnapshotAvailable(sourceDfs, sourcePath, snapshotPrefix, OLD_SNAPSHOT, conf);
+ boolean secondSnapAvailable =
+ SnapshotUtils.isSnapshotAvailable(sourceDfs, sourcePath, snapshotPrefix, NEW_SNAPSHOT, conf);
+ //While resuming a failed replication
if (prevSnaps.contains(sourcePath.toString())) {
// We already created a snapshot for this, just refresh the latest snapshot and leave.
- sourceDfs.deleteSnapshot(sourcePath, secondSnapshot(snapshotPrefix));
- replSnapshotCount.incrementNumDeleted();
+ // In case of reverse replication after fail-over, in some paths, second snapshot may not be present.
+ if(SnapshotUtils.deleteSnapshotIfExists(sourceDfs, sourcePath, secondSnapshot(snapshotPrefix), conf)) {
+ replSnapshotCount.incrementNumDeleted();
+ }
SnapshotUtils.createSnapshot(sourceDfs, sourcePath, secondSnapshot(snapshotPrefix), conf);
replSnapshotCount.incrementNumCreated();
snapPathFileList.add(sourcePath.toString());
return SnapshotUtils
- .isSnapshotAvailable(sourceDfs, sourcePath, snapshotPrefix, OLD_SNAPSHOT, conf) ? DIFF_COPY : INITIAL_COPY;
+ .isSnapshotAvailable(sourceDfs, sourcePath, snapshotPrefix, OLD_SNAPSHOT, conf) ? DIFF_COPY : INITIAL_COPY;
}
- // check if second snapshot exists.
- boolean isSecondSnapAvlb = SnapshotUtils.isSnapshotAvailable(sourceDfs, sourcePath, snapshotPrefix,
- OLD_SNAPSHOT, conf);
- if (isSecondSnapAvlb) {
- sourceDfs.deleteSnapshot(sourcePath, firstSnapshot(snapshotPrefix));
- replSnapshotCount.incrementNumDeleted();
- sourceDfs.renameSnapshot(sourcePath, secondSnapshot(snapshotPrefix), firstSnapshot(snapshotPrefix));
- SnapshotUtils.createSnapshot(sourceDfs, sourcePath, secondSnapshot(snapshotPrefix), conf);
- replSnapshotCount.incrementNumCreated();
- snapPathFileList.add(sourcePath.toString());
- return DIFF_COPY;
- } else {
- // Check if first snapshot is available
- boolean isFirstSnapshotAvailable =
- SnapshotUtils.isSnapshotAvailable(sourceDfs, sourcePath, snapshotPrefix, NEW_SNAPSHOT, conf);
- if (isFirstSnapshotAvailable) {
+
+ //for bootstrap and forward replication
+ if(isBootstrap && !(!secondSnapAvailable && firstSnapAvailable)) {
+ if (conf.getBoolVar(HiveConf.ConfVars.REPL_REUSE_SNAPSHOTS)) {
+ //this can be used in re-bootstrap cases after irrecoverable error
+ if(SnapshotUtils.deleteSnapshotIfExists(sourceDfs, sourcePath, secondSnapshot(snapshotPrefix), conf)) {
+ replSnapshotCount.incrementNumDeleted();
+ }
+ SnapshotUtils.createSnapshot(sourceDfs, sourcePath, secondSnapshot(snapshotPrefix), conf);
+ snapPathFileList.add(sourcePath.toString());
+ replSnapshotCount.incrementNumCreated();
+ return SnapshotUtils
+ .isSnapshotAvailable(sourceDfs, sourcePath, snapshotPrefix, OLD_SNAPSHOT, conf) ? DIFF_COPY : INITIAL_COPY;
+ } else {
Review comment:
This case is included in the following block.
(!secondSnapAvailable && firstSnapAvailable) - this condition denotes reverse replication taking place for the first time for a particular path. So the execution is similar for both incremental and bootstrap - whereby we either reuse the snaps or don't depending upon the conf. For this purpose, this case is clubbed for both.
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