amogh-jahagirdar commented on code in PR #15126:
URL: https://github.com/apache/iceberg/pull/15126#discussion_r2785247722
##########
core/src/test/java/org/apache/iceberg/rest/TestRESTCatalog.java:
##########
@@ -3606,6 +3614,119 @@ protected RESTSessionCatalog newSessionCatalog(
return catalog;
}
+ /**
+ * Test concurrent appends on multiple branches simultaneously to verify
proper handling of
+ * sequence number conflicts.
+ *
+ * <p>Uses a barrier to synchronize threads so they all load the same table
state and commit
+ * simultaneously, creating deterministic conflicts. With retries disabled,
we can verify exact
+ * counts: one success per round, and (numBranches - 1)
CommitFailedExceptions per round.
Review Comment:
It looks like below we don't verify that exactly one success per round (we
just check at least 1), I think this is due to the awaitility and current
barrier setup.
##########
core/src/test/java/org/apache/iceberg/rest/TestRESTCatalog.java:
##########
@@ -3606,6 +3614,119 @@ protected RESTSessionCatalog newSessionCatalog(
return catalog;
}
+ /**
+ * Test concurrent appends on multiple branches simultaneously to verify
proper handling of
+ * sequence number conflicts.
+ *
+ * <p>Uses a barrier to synchronize threads so they all load the same table
state and commit
+ * simultaneously, creating deterministic conflicts. With retries disabled,
we can verify exact
+ * counts: one success per round, and (numBranches - 1)
CommitFailedExceptions per round.
Review Comment:
```
/**
* Test concurrent appends on multiple branches simultaneously to verify
proper handling of
* sequence number conflicts.
*
* <p>Uses CyclicBarrier to synchronize threads so they all load the same
table state and commit
* simultaneously, creating deterministic conflicts. With retries
disabled, we can verify exact
* counts: one success per round, and (numBranches - 1)
CommitFailedExceptions per round.
*
* <p>This verifies that: 1. Sequence number conflicts are caught by
AssertLastSequenceNumber
* requirement 2. Conflicts result in CommitFailedException (retryable)
not ValidationException
* (non-retryable) 3. The REST catalog properly handles concurrent
modifications across branches
*/
@Test
public void testConcurrentAppendsOnMultipleBranches() {
int numBranches = 5;
int numRounds = 10;
RESTCatalog catalog = catalog();
Namespace ns = Namespace.of("concurrent_test");
TableIdentifier tableIdent = TableIdentifier.of(ns, "test_table");
catalog.createNamespace(ns);
Table table = catalog.buildTable(tableIdent,
SCHEMA).withPartitionSpec(SPEC).create();
// Disable retries so we can count exact conflicts
table.updateProperties().set(TableProperties.COMMIT_NUM_RETRIES,
"-1").commit();
// Create branches from the main branch
String[] branchNames = new String[numBranches];
ManageSnapshots manageSnapshots = table.manageSnapshots();
for (int i = 0; i < numBranches; i++) {
branchNames[i] = "branch-" + i;
manageSnapshots = manageSnapshots.createBranch(branchNames[i]);
}
manageSnapshots.commit();
CyclicBarrier startBarrier = new CyclicBarrier(numBranches);
CyclicBarrier endBarrier = new CyclicBarrier(numBranches);
AtomicIntegerArray successPerRound = new AtomicIntegerArray(numRounds);
AtomicIntegerArray failuresPerRound = new AtomicIntegerArray(numRounds);
AtomicInteger validationFailureCount = new AtomicInteger(0);
ExecutorService executor =
MoreExecutors.getExitingExecutorService(
(ThreadPoolExecutor) Executors.newFixedThreadPool(numBranches));
Tasks.range(numBranches)
.stopOnFailure()
.throwFailureWhenFinished()
.executeWith(executor)
.run(
branchIdx -> {
String branchName = branchNames[branchIdx];
for (int round = 0; round < numRounds; round++) {
// Load table
Table localTable = catalog.loadTable(tableIdent);
DataFile newFile =
DataFiles.builder(SPEC)
.withPath(
String.format("/path/to/branch-%d-round-%d.parquet", branchIdx, round))
.withFileSizeInBytes(15)
.withPartitionPath(String.format("id_bucket=%d",
branchIdx % 16))
.withRecordCount(3)
.build();
try {
// Wait for all threads to be ready to commit
startBarrier.await();
// All threads commit simultaneously
localTable.newFastAppend().appendFile(newFile).toBranch(branchName).commit();
successPerRound.incrementAndGet(round);
} catch (CommitFailedException e) {
// Expected for conflicts - this is the correct behavior
with the fix
failuresPerRound.incrementAndGet(round);
} catch (ValidationException e) {
// This indicates the fix is not working
validationFailureCount.incrementAndGet();
throw e;
} catch (Exception e) {
// Handle barrier exceptions
throw new RuntimeException(e);
}
try {
// Ensure all threads complete this round before starting
the next
endBarrier.await();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
});
executor.shutdown();
int totalAttempts = numBranches * numRounds;
// Verify: no ValidationException should have been thrown
assertThat(validationFailureCount.get())
.as(
"Sequence number conflicts should throw CommitFailedException
(retryable), "
+ "not ValidationException")
.isEqualTo(0);
// Verify per-round exactly one success and (numBranches - 1) failures
per round
for (int round = 0; round < numRounds; round++) {
assertThat(successPerRound.get(round))
.as("Exactly one commit should succeed in round " + round)
.isEqualTo(1);
assertThat(failuresPerRound.get(round))
.as("Exactly (numBranches - 1) commits should fail in round " +
round)
.isEqualTo(numBranches - 1);
}
// Verify no attempts were lost
int totalSuccesses = 0;
int totalFailures = 0;
for (int round = 0; round < numRounds; round++) {
totalSuccesses += successPerRound.get(round);
totalFailures += failuresPerRound.get(round);
}
assertThat(totalSuccesses)
.as("Total successes should equal number of rounds")
.isEqualTo(numRounds);
assertThat(totalSuccesses + totalFailures)
.as("All commit attempts should either succeed or fail with
CommitFailedException")
.isEqualTo(totalAttempts);
}
```
This is what I have locally. I changed it a bit so we can guarantee that
there's exactly one, and some minor improvements so we don't do a commit on
every branch creation (we can just do it in a single commit).
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