Skip to content

HBASE-29109 Downgrade to shared lock at the time of prepare snapshot itself #6919

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
virajjasani merged 1 commit into from
Apr 27, 2025
Merged

HBASE-29109 Downgrade to shared lock at the time of prepare snapshot itself #6919

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
31 changes: 16 additions & 15 deletions hbase-server/src/main/java/org/apache/hadoop/hbase/master/snapshot/TakeSnapshotHandler.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -88,7 +88,7 @@ public abstract class TakeSnapshotHandler extends EventHandler
protected final Path workingDir;
private final MasterSnapshotVerifier verifier;
protected final ForeignExceptionDispatcher monitor;
private final LockManager.MasterLock tableLock;
private LockManager.MasterLock tableLock;
protected final MonitoredTask status;
protected final TableName snapshotTable;
protected final SnapshotManifest snapshotManifest;
Expand Down Expand Up @@ -167,17 +167,30 @@ public TakeSnapshotHandler prepare() throws Exception {
if (this.tableLock.tryAcquire(this.lockAcquireTimeoutMs)) {
try {
this.htd = loadTableDescriptor(); // check that .tableinfo is present
if (downgradeToSharedTableLock()) {
// release the exclusive lock and hold the shared lock instead
this.tableLock.release();
this.tableLock = master.getLockManager().createMasterLock(snapshotTable, LockType.SHARED,
this.getClass().getName() + ": take snapshot " + snapshot.getName());
if (!this.tableLock.tryAcquire(this.lockAcquireTimeoutMs)) {
throwLockNotAcquiredException();
}
}
} catch (Exception e) {
this.tableLock.release();
throw e;
}
} else {
LOG.error("Master lock could not be acquired in {} ms", lockAcquireTimeoutMs);
throw new DoNotRetryIOException("Master lock could not be acquired");
throwLockNotAcquiredException();
}
return this;
}

private void throwLockNotAcquiredException() throws DoNotRetryIOException {
LOG.error("Master lock could not be acquired in {} ms", lockAcquireTimeoutMs);
throw new DoNotRetryIOException("Master lock could not be acquired");
}

/**
* Execute the core common portions of taking a snapshot. The {@link #snapshotRegions(List)} call
* should get implemented for each snapshot flavor.
Expand All @@ -192,18 +205,6 @@ public void process() {
MasterLock tableLockToRelease = this.tableLock;
status.setStatus(msg);
try {
if (downgradeToSharedTableLock()) {
// release the exclusive lock and hold the shared lock instead
tableLockToRelease = master.getLockManager().createMasterLock(snapshotTable,
LockType.SHARED, this.getClass().getName() + ": take snapshot " + snapshot.getName());
tableLock.release();
boolean isTableLockAcquired = tableLockToRelease.tryAcquire(this.lockAcquireTimeoutMs);
if (!isTableLockAcquired) {
LOG.error("Could not acquire shared lock on table {} in {} ms", snapshotTable,
lockAcquireTimeoutMs);
throw new IOException("Could not acquire shared lock on table " + snapshotTable);
}
}
// If regions move after this meta scan, the region specific snapshot should fail, triggering
// an external exception that gets captured here.

Expand Down