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HBASE-29604 BackupHFileCleaner uses flawed time based check#7360

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Merged
ndimiduk merged 1 commit into from
Oct 10, 2025
Merged

HBASE-29604 BackupHFileCleaner uses flawed time based check #7360

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17 changes: 10 additions & 7 deletions hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/BackupHFileCleaner.java
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Expand Up@@ -52,10 +52,13 @@ public class BackupHFileCleaner extends BaseHFileCleanerDelegate implements Abor
private boolean stopped = false;
private boolean aborted = false;
private Connection connection;
// timestamp of most recent read from backup system table
private long prevReadFromBackupTbl = 0;
// timestamp of 2nd most recent read from backup system table
private long secondPrevReadFromBackupTbl = 0;
// timestamp of most recent completed cleaning run
private volatile long previousCleaningCompletionTimestamp = 0;

@ndimidukndimidukOct 7, 2025

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So the first run of the chore during the process lifecycle will always do nothing? Is there something else we can base it's initialization value on?

@DieterDP-ngDieterDP-ngOct 7, 2025

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Correct. That was also the (intended, but not actual) behavior of this cleaner before this PR I think.

I guess we can just initialize this to X time before the current time. Could pick X rudimentary, I think a minute is sufficient, or we could set X to the interval in which the cleaner runs, if I trace the code correctly, that would be the value of hbase.master.cleaner.interval.


@Override
public void postClean() {

@krconvkrconvOct 7, 2025

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I agree that this definitely looks like an oversight from the original implementation, and that this change corrects it to work as it seems it was originally intended

previousCleaningCompletionTimestamp = EnvironmentEdgeManager.currentTime();
}

@Override
public Iterable<FileStatus> getDeletableFiles(Iterable<FileStatus> files) {
Expand All@@ -79,12 +82,12 @@ public Iterable<FileStatus> getDeletableFiles(Iterable<FileStatus> files) {
return Collections.emptyList();
}

secondPrevReadFromBackupTbl = prevReadFromBackupTbl;
prevReadFromBackupTbl = EnvironmentEdgeManager.currentTime();
// Pin the threshold, we don't want the result to change depending on evaluation time.
final long recentFileThreshold = previousCleaningCompletionTimestamp;

return Iterables.filter(files, file -> {
// If the file is recent, be conservative and wait for one more scan of the bulk loads
if (file.getModificationTime() > secondPrevReadFromBackupTbl) {
if (file.getModificationTime() > recentFileThreshold) {
LOG.debug("Preventing deletion due to timestamp: {}", file.getPath().toString());
return false;
}
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13 changes: 10 additions & 3 deletions hbase-backup/src/test/java/org/apache/hadoop/hbase/backup/TestBackupHFileCleaner.java
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Expand Up@@ -108,11 +108,11 @@ protected Set<TableName> fetchFullyBackedUpTables(BackupSystemTable tbl) {
Iterable<FileStatus> deletable;

// The first call will not allow any deletions because of the timestamp mechanism.
deletable = cleaner.getDeletableFiles(List.of(file1, file1Archived, file2, file3));
deletable = callCleaner(cleaner, List.of(file1, file1Archived, file2, file3));
assertEquals(Set.of(), Sets.newHashSet(deletable));

// No bulk loads registered, so all files can be deleted.
deletable = cleaner.getDeletableFiles(List.of(file1, file1Archived, file2, file3));
deletable = callCleaner(cleaner, List.of(file1, file1Archived, file2, file3));
assertEquals(Set.of(file1, file1Archived, file2, file3), Sets.newHashSet(deletable));

// Register some bulk loads.
Expand All@@ -125,10 +125,17 @@ protected Set<TableName> fetchFullyBackedUpTables(BackupSystemTable tbl) {
}

// File 1 can no longer be deleted, because it is registered as a bulk load.
deletable = cleaner.getDeletableFiles(List.of(file1, file1Archived, file2, file3));
deletable = callCleaner(cleaner, List.of(file1, file1Archived, file2, file3));
assertEquals(Set.of(file2, file3), Sets.newHashSet(deletable));
}

private Iterable<FileStatus> callCleaner(BackupHFileCleaner cleaner, Iterable<FileStatus> files) {
cleaner.preClean();
Iterable<FileStatus> deletable = cleaner.getDeletableFiles(files);
cleaner.postClean();
return deletable;
}

private FileStatus createFile(String fileName) throws IOException {
Path file = new Path(root, fileName);
fs.createNewFile(file);
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4 changes: 4 additions & 0 deletions ...-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/BaseFileCleanerDelegate.java
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Expand Up@@ -44,6 +44,10 @@ public void init(Map<String, Object> params) {

/**
* Should the master delete the file or keep it?
* <p>
* This method can be called concurrently by multiple threads. Implementations must be thread
* safe.
* </p>
* @param fStat file status of the file to check
* @return <tt>true</tt> if the file is deletable, <tt>false</tt> if not
*/
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4 changes: 4 additions & 0 deletions hbase-server/src/main/java/org/apache/hadoop/hbase/master/cleaner/FileCleanerDelegate.java
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Expand Up@@ -33,6 +33,10 @@ public interface FileCleanerDelegate extends Configurable, Stoppable {

/**
* Determines which of the given files are safe to delete
* <p>
* This method can be called concurrently by multiple threads. Implementations must be thread
* safe.
* </p>
* @param files files to check for deletion
* @return files that are ok to delete according to this cleaner
*/
Expand Down