Examples with LogAppendEvent org.neo4j.kernel.impl.transaction.tracing.LogAppendEvent used on opensource projects

Example 1 with LogAppendEvent

use of org.neo4j.kernel.impl.transaction.tracing.LogAppendEvent in project neo4j by neo4j.

the class BatchingTransactionAppenderConcurrencyTest method shouldHaveAllConcurrentAppendersSeePanic.

/*
     * There was an issue where if multiple concurrent appending threads did append and they moved on
     * to await a force, where the force would fail and the one doing the force would raise a panic...
     * the other threads may not notice the panic and move on to mark those transactions as committed
     * and notice the panic later (which would be too late).
     */
@Test
public void shouldHaveAllConcurrentAppendersSeePanic() throws Throwable {
    // GIVEN
    Adversary adversary = new ClassGuardedAdversary(new CountingAdversary(1, true), failMethod(BatchingTransactionAppender.class, "force"));
    EphemeralFileSystemAbstraction efs = new EphemeralFileSystemAbstraction();
    File directory = new File("dir").getCanonicalFile();
    efs.mkdirs(directory);
    FileSystemAbstraction fs = new AdversarialFileSystemAbstraction(adversary, efs);
    life.add(new FileSystemLifecycleAdapter(fs));
    DatabaseHealth databaseHealth = new DatabaseHealth(mock(DatabasePanicEventGenerator.class), NullLog.getInstance());
    PhysicalLogFiles logFiles = new PhysicalLogFiles(directory, fs);
    LogFile logFile = life.add(new PhysicalLogFile(fs, logFiles, kibiBytes(10), transactionIdStore::getLastCommittedTransactionId, new DeadSimpleLogVersionRepository(0), new PhysicalLogFile.Monitor.Adapter(), logHeaderCache));
    final BatchingTransactionAppender appender = life.add(new BatchingTransactionAppender(logFile, logRotation, transactionMetadataCache, transactionIdStore, legacyIndexTransactionOrdering, databaseHealth));
    life.start();
    // WHEN
    int numberOfAppenders = 10;
    final CountDownLatch trap = new CountDownLatch(numberOfAppenders);
    final LogAppendEvent beforeForceTrappingEvent = new LogAppendEvent.Empty() {

        @Override
        public LogForceWaitEvent beginLogForceWait() {
            trap.countDown();
            awaitLatch(trap);
            return super.beginLogForceWait();
        }
    };
    Race race = new Race();
    for (int i = 0; i < numberOfAppenders; i++) {
        race.addContestant(() -> {
            try {
                // Append to the log, the LogAppenderEvent will have all of the appending threads
                // do wait for all of the other threads to start the force thing
                appender.append(tx(), beforeForceTrappingEvent);
                fail("No transaction should be considered appended");
            } catch (IOException e) {
            // Good, we know that this test uses an adversarial file system which will throw
            // an exception in BatchingTransactionAppender#force, and since all these transactions
            // will append and be forced in the same batch, where the force will fail then
            // all these transactions should fail. If there's any transaction not failing then
            // it just didn't notice the panic, which would be potentially hazardous.
            }
        });
    }
    // THEN perform the race. The relevant assertions are made inside the contestants.
    race.go();
}