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ConstraintIndexCreator.java
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ConstraintIndexCreator.java
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/*
* Copyright (c) 2002-2018 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.kernel.impl.api.state;
import java.io.IOException;
import java.util.function.Supplier;
import org.neo4j.internal.kernel.api.CapableIndexReference;
import org.neo4j.internal.kernel.api.SchemaRead;
import org.neo4j.internal.kernel.api.TokenRead;
import org.neo4j.internal.kernel.api.exceptions.schema.SchemaKernelException;
import org.neo4j.internal.kernel.api.exceptions.schema.SchemaKernelException.OperationContext;
import org.neo4j.internal.kernel.api.schema.LabelSchemaDescriptor;
import org.neo4j.kernel.api.InwardKernel;
import org.neo4j.kernel.api.KernelTransaction;
import org.neo4j.kernel.api.SilentTokenNameLookup;
import org.neo4j.kernel.api.Statement;
import org.neo4j.kernel.api.StatementTokenNameLookup;
import org.neo4j.kernel.api.exceptions.TransactionFailureException;
import org.neo4j.kernel.api.exceptions.index.IndexEntryConflictException;
import org.neo4j.kernel.api.exceptions.index.IndexNotFoundKernelException;
import org.neo4j.kernel.api.exceptions.index.IndexPopulationFailedKernelException;
import org.neo4j.kernel.api.exceptions.schema.AlreadyConstrainedException;
import org.neo4j.kernel.api.exceptions.schema.AlreadyIndexedException;
import org.neo4j.kernel.api.exceptions.schema.CreateConstraintFailureException;
import org.neo4j.kernel.api.exceptions.schema.SchemaRuleNotFoundException;
import org.neo4j.kernel.api.exceptions.schema.UniquePropertyValueValidationException;
import org.neo4j.kernel.api.index.PropertyAccessor;
import org.neo4j.kernel.api.schema.constaints.ConstraintDescriptorFactory;
import org.neo4j.kernel.api.schema.constaints.UniquenessConstraintDescriptor;
import org.neo4j.kernel.api.schema.index.SchemaIndexDescriptor;
import org.neo4j.kernel.api.schema.index.SchemaIndexDescriptor.Type;
import org.neo4j.kernel.api.schema.index.SchemaIndexDescriptorFactory;
import org.neo4j.kernel.impl.api.KernelStatement;
import org.neo4j.kernel.impl.api.KernelTransactionImplementation;
import org.neo4j.kernel.impl.api.index.IndexProxy;
import org.neo4j.kernel.impl.api.index.IndexingService;
import org.neo4j.kernel.impl.api.operations.SchemaReadOperations;
import org.neo4j.kernel.impl.api.store.DefaultCapableIndexReference;
import org.neo4j.kernel.impl.locking.Locks.Client;
import static org.neo4j.internal.kernel.api.exceptions.schema.ConstraintValidationException.Phase.VERIFICATION;
import static org.neo4j.internal.kernel.api.exceptions.schema.SchemaKernelException.OperationContext
.CONSTRAINT_CREATION;
import static org.neo4j.internal.kernel.api.security.SecurityContext.AUTH_DISABLED;
import static org.neo4j.kernel.impl.locking.ResourceTypes.LABEL;
public class ConstraintIndexCreator
{
private final IndexingService indexingService;
private final Supplier<InwardKernel> kernelSupplier;
private final PropertyAccessor propertyAccessor;
public ConstraintIndexCreator( Supplier<InwardKernel> kernelSupplier, IndexingService indexingService,
PropertyAccessor propertyAccessor )
{
this.kernelSupplier = kernelSupplier;
this.indexingService = indexingService;
this.propertyAccessor = propertyAccessor;
}
@Deprecated
public long createUniquenessConstraintIndex(
KernelStatement state, SchemaReadOperations schemaOps, LabelSchemaDescriptor descriptor
) throws TransactionFailureException, CreateConstraintFailureException, UniquePropertyValueValidationException,
AlreadyConstrainedException
{
UniquenessConstraintDescriptor constraint = ConstraintDescriptorFactory.uniqueForSchema( descriptor );
SchemaIndexDescriptor index;
try
{
index = getOrCreateUniquenessConstraintIndex( state, schemaOps, descriptor );
}
catch ( AlreadyConstrainedException e )
{
throw e;
}
catch ( SchemaKernelException e )
{
throw new CreateConstraintFailureException( constraint, e );
}
boolean success = false;
boolean reacquiredLabelLock = false;
Client locks = state.locks().pessimistic();
try
{
long indexId = schemaOps.indexGetCommittedId( state, 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
releaseLabelLock( locks, descriptor.getLabelId() );
awaitConstrainIndexPopulation( constraint, proxy );
// 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.
acquireLabelLock( state, locks, descriptor.getLabelId() );
reacquiredLabelLock = true;
indexingService.getIndexProxy( indexId ).verifyDeferredConstraints( propertyAccessor );
success = true;
return indexId;
}
catch ( SchemaRuleNotFoundException e )
{
throw new IllegalStateException(
String.format( "Index (%s) that we just created does not exist.", descriptor ), e );
}
catch ( IndexNotFoundKernelException e )
{
throw new TransactionFailureException(
String.format( "Index (%s) that we just created does not exist.", descriptor ), e );
}
catch ( IndexEntryConflictException e )
{
throw new UniquePropertyValueValidationException( constraint, VERIFICATION, e );
}
catch ( InterruptedException | IOException e )
{
throw new CreateConstraintFailureException( constraint, e );
}
finally
{
if ( !success )
{
if ( !reacquiredLabelLock )
{
acquireLabelLock( state, locks, descriptor.getLabelId() );
}
if ( indexStillExists( schemaOps, state, descriptor, index ) )
{
dropUniquenessConstraintIndex( index );
}
}
}
}
/**
* 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>
*/
public long createUniquenessConstraintIndex( KernelTransactionImplementation transaction,
LabelSchemaDescriptor descriptor ) throws TransactionFailureException, CreateConstraintFailureException,
UniquePropertyValueValidationException, AlreadyConstrainedException
{
UniquenessConstraintDescriptor constraint = ConstraintDescriptorFactory.uniqueForSchema( descriptor );
CapableIndexReference index;
SchemaRead schemaRead = transaction.schemaRead();
try
{
index = getOrCreateUniquenessConstraintIndex( schemaRead, transaction.tokenRead(), descriptor );
}
catch ( AlreadyConstrainedException e )
{
throw e;
}
catch ( SchemaKernelException | IndexNotFoundKernelException e )
{
throw new CreateConstraintFailureException( constraint, e );
}
boolean success = false;
boolean reacquiredLabelLock = false;
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
releaseLabelLock( locks, descriptor.getLabelId() );
awaitConstrainIndexPopulation( constraint, proxy );
// 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.
acquireLabelLock( transaction, locks, descriptor.getLabelId() );
reacquiredLabelLock = true;
indexingService.getIndexProxy( indexId ).verifyDeferredConstraints( propertyAccessor );
success = true;
return indexId;
}
catch ( SchemaKernelException e )
{
throw new IllegalStateException(
String.format( "Index (%s) that we just created does not exist.", descriptor ), e );
}
catch ( IndexNotFoundKernelException e )
{
throw new TransactionFailureException(
String.format( "Index (%s) that we just created does not exist.", descriptor ), e );
}
catch ( IndexEntryConflictException e )
{
throw new UniquePropertyValueValidationException( constraint, VERIFICATION, e );
}
catch ( InterruptedException | IOException e )
{
throw new CreateConstraintFailureException( constraint, e );
}
finally
{
if ( !success )
{
if ( !reacquiredLabelLock )
{
acquireLabelLock( transaction, locks, descriptor.getLabelId() );
}
if ( indexStillExists( schemaRead, descriptor, index ) )
{
dropUniquenessConstraintIndex( asDescriptor( index ) );
}
}
}
}
private boolean indexStillExists( SchemaReadOperations schemaOps, KernelStatement state,
LabelSchemaDescriptor descriptor, SchemaIndexDescriptor index )
{
SchemaIndexDescriptor existingIndex = schemaOps.indexGetForSchema( state, descriptor );
return existingIndex != null && existingIndex.equals( index );
}
private boolean indexStillExists( SchemaRead schemaRead, LabelSchemaDescriptor descriptor,
CapableIndexReference index )
{
CapableIndexReference existingIndex = schemaRead.index( descriptor.getLabelId(), descriptor.getPropertyIds() );
return existingIndex != CapableIndexReference.NO_INDEX && existingIndex.equals( index );
}
private void acquireLabelLock( KernelStatement state, Client locks, int labelId )
{
locks.acquireExclusive( state.lockTracer(), LABEL, labelId );
}
private void acquireLabelLock( KernelTransactionImplementation state, Client locks, int labelId )
{
locks.acquireExclusive( state.lockTracer(), LABEL, labelId );
}
private void releaseLabelLock( Client locks, int labelId )
{
locks.releaseExclusive( LABEL, labelId );
}
/**
* You MUST hold a schema write lock before you call this method.
*/
public void dropUniquenessConstraintIndex( SchemaIndexDescriptor descriptor )
throws TransactionFailureException
{
try ( KernelTransaction transaction =
kernelSupplier.get().newTransaction( KernelTransaction.Type.implicit, AUTH_DISABLED );
Statement ignore = transaction.acquireStatement() )
{
((KernelTransactionImplementation) transaction).txState().indexDoDrop( descriptor );
transaction.success();
}
}
private SchemaIndexDescriptor asDescriptor( CapableIndexReference indexReference )
{
if ( indexReference.isUnique() )
{
return SchemaIndexDescriptorFactory.uniqueForLabel( indexReference.label(), indexReference.properties() );
}
else
{
return SchemaIndexDescriptorFactory.forLabel( indexReference.label(), indexReference.properties() );
}
}
private void awaitConstrainIndexPopulation( UniquenessConstraintDescriptor constraint, IndexProxy proxy )
throws InterruptedException, UniquePropertyValueValidationException
{
try
{
proxy.awaitStoreScanCompleted();
}
catch ( IndexPopulationFailedKernelException e )
{
Throwable cause = e.getCause();
if ( cause instanceof IndexEntryConflictException )
{
throw new UniquePropertyValueValidationException(
constraint, VERIFICATION, (IndexEntryConflictException) cause );
}
else
{
throw new UniquePropertyValueValidationException( constraint, VERIFICATION, e );
}
}
}
private SchemaIndexDescriptor getOrCreateUniquenessConstraintIndex( KernelStatement state, SchemaReadOperations schemaOps,
LabelSchemaDescriptor schema ) throws SchemaKernelException
{
SchemaIndexDescriptor descriptor = schemaOps.indexGetForSchema( state, schema );
if ( descriptor != null )
{
if ( descriptor.type() == Type.UNIQUE )
{
// OK so we found a matching constraint index. We check whether or not it has an owner
// because this may have been a left-over constraint index from a previously failed
// constraint creation, due to crash or similar, hence the missing owner.
if ( schemaOps.indexGetOwningUniquenessConstraintId( state, descriptor ) == null )
{
return descriptor;
}
throw new AlreadyConstrainedException(
ConstraintDescriptorFactory.uniqueForSchema( schema ),
OperationContext.CONSTRAINT_CREATION,
new StatementTokenNameLookup( state.readOperations() ) );
}
// There's already an index for this schema descriptor, which isn't of the type we're after.
throw new AlreadyIndexedException( schema, CONSTRAINT_CREATION );
}
return createConstraintIndex( schema );
}
private CapableIndexReference getOrCreateUniquenessConstraintIndex( SchemaRead schemaRead,
TokenRead tokenRead, LabelSchemaDescriptor schema )
throws SchemaKernelException, IndexNotFoundKernelException
{
CapableIndexReference descriptor = schemaRead.index( schema.getLabelId(), schema.getPropertyIds() );
if ( descriptor != CapableIndexReference.NO_INDEX )
{
if ( descriptor.isUnique() )
{
// OK so we found a matching constraint index. We check whether or not it has an owner
// because this may have been a left-over constraint index from a previously failed
// constraint creation, due to crash or similar, hence the missing owner.
if ( schemaRead.indexGetOwningUniquenessConstraintId( descriptor ) == null )
{
return descriptor;
}
throw new AlreadyConstrainedException(
ConstraintDescriptorFactory.uniqueForSchema( schema ),
OperationContext.CONSTRAINT_CREATION,
new SilentTokenNameLookup( tokenRead ) );
}
// There's already an index for this schema descriptor, which isn't of the type we're after.
throw new AlreadyIndexedException( schema, CONSTRAINT_CREATION );
}
SchemaIndexDescriptor indexDescriptor = createConstraintIndex( schema );
IndexProxy indexProxy = indexingService.getIndexProxy( indexDescriptor.schema() );
return new DefaultCapableIndexReference( indexDescriptor.type() == Type.UNIQUE, indexProxy.getIndexCapability(),
indexProxy.getProviderDescriptor(), indexDescriptor.schema().getLabelId(),
indexDescriptor.schema().getPropertyIds() );
}
public SchemaIndexDescriptor createConstraintIndex( final LabelSchemaDescriptor schema )
{
try ( KernelTransaction transaction =
kernelSupplier.get().newTransaction( KernelTransaction.Type.implicit, AUTH_DISABLED );
Statement ignore = transaction.acquireStatement() )
{
SchemaIndexDescriptor index = SchemaIndexDescriptorFactory.uniqueForSchema( schema );
((KernelTransactionImplementation) transaction).txState().indexRuleDoAdd( index );
transaction.success();
return index;
}
catch ( TransactionFailureException e )
{
throw new RuntimeException( e );
}
}
}