public override void doWork(Locks_Client client)
{
client.ReleaseExclusive(_resourceType, _key);
}
/// <summary>
/// You MUST hold a label write lock before you call this method.
/// However the label write lock is temporarily released while populating the index backing the constraint.
/// It goes a little like this:
/// <ol>
/// <li>Prerequisite: Getting here means that there's an open schema transaction which has acquired the
/// LABEL WRITE lock.</li>
/// <li>Index schema rule which is backing the constraint is created in a nested mini-transaction
/// which doesn't acquire any locking, merely adds tx state and commits so that the index rule is applied
/// to the store, which triggers the index population</li>
/// <li>Release the LABEL WRITE lock</li>
/// <li>Await index population to complete</li>
/// <li>Acquire the LABEL WRITE lock (effectively blocking concurrent transactions changing
/// data related to this constraint, and it so happens, most other transactions as well) and verify
/// the uniqueness of the built index</li>
/// <li>Leave this method, knowing that the uniqueness constraint rule will be added to tx state
/// and this tx committed, which will create the uniqueness constraint</li>
/// </ol>
/// </summary>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in C#:
//ORIGINAL LINE: public long createUniquenessConstraintIndex(org.neo4j.kernel.impl.api.KernelTransactionImplementation transaction, org.neo4j.internal.kernel.api.schema.SchemaDescriptor descriptor, String provider) throws org.neo4j.internal.kernel.api.exceptions.TransactionFailureException, org.neo4j.internal.kernel.api.exceptions.schema.CreateConstraintFailureException, org.neo4j.kernel.api.exceptions.schema.UniquePropertyValueValidationException, org.neo4j.kernel.api.exceptions.schema.AlreadyConstrainedException
public virtual long CreateUniquenessConstraintIndex(KernelTransactionImplementation transaction, SchemaDescriptor descriptor, string provider)
{
UniquenessConstraintDescriptor constraint = ConstraintDescriptorFactory.uniqueForSchema(descriptor);
_log.info("Starting constraint creation: %s.", constraint.OwnedIndexDescriptor());
IndexReference index;
SchemaRead schemaRead = transaction.SchemaRead();
try
{
index = GetOrCreateUniquenessConstraintIndex(schemaRead, transaction.TokenRead(), descriptor, provider);
}
catch (AlreadyConstrainedException e)
{
throw e;
}
catch (Exception e) when(e is SchemaKernelException || e is IndexNotFoundKernelException)
{
throw new CreateConstraintFailureException(constraint, e);
}
bool success = false;
bool reacquiredLabelLock = false;
Locks_Client locks = transaction.StatementLocks().pessimistic();
try
{
long indexId = schemaRead.IndexGetCommittedId(index);
IndexProxy proxy = _indexingService.getIndexProxy(indexId);
// Release the LABEL WRITE lock during index population.
// At this point the integrity of the constraint to be created was checked
// while holding the lock and the index rule backing the soon-to-be-created constraint
// has been created. Now it's just the population left, which can take a long time
locks.ReleaseExclusive(descriptor.KeyType(), descriptor.KeyId());
AwaitConstraintIndexPopulation(constraint, proxy, transaction);
_log.info("Constraint %s populated, starting verification.", constraint.OwnedIndexDescriptor());
// Index population was successful, but at this point we don't know if the uniqueness constraint holds.
// Acquire LABEL WRITE lock and verify the constraints here in this user transaction
// and if everything checks out then it will be held until after the constraint has been
// created and activated.
locks.AcquireExclusive(transaction.LockTracer(), descriptor.KeyType(), descriptor.KeyId());
reacquiredLabelLock = true;
_indexingService.getIndexProxy(indexId).verifyDeferredConstraints(_nodePropertyAccessor);
_log.info("Constraint %s verified.", constraint.OwnedIndexDescriptor());
success = true;
return(indexId);
}
catch (SchemaKernelException e)
{
throw new System.InvalidOperationException(string.Format("Index ({0}) that we just created does not exist.", descriptor), e);
}
catch (IndexNotFoundKernelException e)
{
throw new TransactionFailureException(string.Format("Index ({0}) that we just created does not exist.", descriptor), e);
}
catch (IndexEntryConflictException e)
{
throw new UniquePropertyValueValidationException(constraint, VERIFICATION, e);
}
catch (Exception e) when(e is InterruptedException || e is IOException)
{
throw new CreateConstraintFailureException(constraint, e);
}
finally
{
if (!success)
{
if (!reacquiredLabelLock)
{
locks.AcquireExclusive(transaction.LockTracer(), descriptor.KeyType(), descriptor.KeyId());
}
if (IndexStillExists(schemaRead, descriptor, index))
{
DropUniquenessConstraintIndex(( IndexDescriptor )index);
}
}
}
}
