/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program 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; version 2 of the License.
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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Dec 12, 2006
*/
package com.bigdata.btree;
import java.util.UUID;
import com.bigdata.btree.keys.TestKeyBuilder;
import com.bigdata.cache.HardReferenceQueue;
import com.bigdata.rawstore.IRawStore;
import com.bigdata.rawstore.SimpleMemoryRawStore;
/**
* Test suite for {@link BTree#touch(AbstractNode)}. None of these tests cause
* an evicted node to be made persistent, but they do verify the correct
* tracking of the {@link AbstractNode#referenceCount} and the contract for
* touching a node.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class TestTouch extends AbstractBTreeTestCase {
/**
*
*/
public TestTouch() {
}
/**
* @param name
*/
public TestTouch(String name) {
super(name);
}
/**
* Test verifies that the reference counter is incremented when a node is
* appended to the hard reference queue (the scan of the tail of the queue
* is disabled for this test). Finally, verify that we can force the node to
* be evicted from the queue but that its non-zero reference counter means
* that it is not made persistent when it is evicted.
*/
public void test_touch01() {
/*
* setup the btree with a queue having two entries and no scanning. The
* listener initially disallows any evictions and we have to explicitly
* notify the listener when it should expect an eviction.
*/
final int branchingFactor = 3;
final MyEvictionListener listener = new MyEvictionListener();
final int queueCapacity = 2;
final int queueScan = 0;
final MyHardReferenceQueue<PO> leafQueue = new MyHardReferenceQueue<PO>(
listener, queueCapacity, queueScan);
assertEquals(queueCapacity,leafQueue.capacity());
assertEquals(queueScan,leafQueue.nscan());
assertEquals(listener,leafQueue.getListener());
/*
* Setup the B+Tree directly so that we can override the hard reference
* queue.
*/
final BTree btree;
{
IRawStore store = new SimpleMemoryRawStore();
IndexMetadata metadata = new IndexMetadata(UUID.randomUUID());
metadata.setBranchingFactor(branchingFactor);
metadata.write(store);
Checkpoint checkpoint = metadata.firstCheckpoint();
checkpoint.write(store);
btree = new BTree(store,checkpoint,metadata,false/*readOnly*/) {
@Override
protected HardReferenceQueue<PO> newWriteRetentionQueue(final boolean readOnly) {
return leafQueue;
}
};
}
// The btree.
// final BTree btree = new BTree(
// new SimpleMemoryRawStore(),
// branchingFactor,
// UUID.randomUUID(),
// false,//isolatable
// null,//conflictResolver
// leafQueue,
// KeyBufferSerializer.INSTANCE,
// ByteArrayValueSerializer.INSTANCE,
// null // no record compressor
// );
/*
* verify the initial conditions - the root leaf is on the queue and
* its reference counter is one (1).
*/
final Leaf a = (Leaf)btree.getRoot();
assertEquals(1,a.referenceCount);
assertEquals(new PO[]{a}, leafQueue.toArray(new PO[0]));
/*
* touch the leaf. since we are not scanning the queue, another
* reference to the leaf will be added to the queue and the reference
* counter will be incremented.
*/
btree.touch(a);
assertEquals(2,a.referenceCount);
assertEquals(new PO[]{a,a}, leafQueue.toArray(new PO[0]));
/*
* touch the leaf. since the queue is at capacity, the leaf is evicted.
* We verify that leaf has a non-zero reference counter when it is
* evicted, which means that it will not be made persistent since other
* references to the leaf remain on the queue.
*/
listener.setExpectedRef(a);
btree.touch(a);
assertEquals(2,a.referenceCount);
assertEquals(new PO[]{a,a}, leafQueue.toArray(new PO[0]));
assertFalse(a.isPersistent());
}
/**
* Test verifies that the reference counter is unchanged across
* {@link BTree#touch(AbstractNode)} if a node is already on the hard
* reference queue.
*/
public void test_touch02() {
/*
* setup the btree with a queue having two entries and scanning. The
* listener initially disallows any evictions and we have to explicitly
* notify the listener when it should expect an eviction.
*/
final int branchingFactor = 3;
final MyEvictionListener listener = new MyEvictionListener();
final int queueCapacity = 2;
final int queueScan = 1;
final MyHardReferenceQueue<PO> leafQueue = new MyHardReferenceQueue<PO>(
listener, queueCapacity, queueScan);
assertEquals(queueCapacity,leafQueue.capacity());
assertEquals(queueScan,leafQueue.nscan());
assertEquals(listener,leafQueue.getListener());
/*
* Setup the B+Tree directly so that we can override the hard reference
* queue.
*/
final BTree btree;
{
IRawStore store = new SimpleMemoryRawStore();
IndexMetadata metadata = new IndexMetadata(UUID.randomUUID());
metadata.setBranchingFactor(branchingFactor);
metadata.write(store);
Checkpoint checkpoint = metadata.firstCheckpoint();
checkpoint.write(store);
btree = new BTree(store,checkpoint,metadata, false/*readOnly*/) {
@Override
protected HardReferenceQueue<PO> newWriteRetentionQueue(final boolean readOnly) {
return leafQueue;
}
};
}
// // The btree.
// final BTree btree = new BTree(
// new SimpleMemoryRawStore(),
// branchingFactor,
// UUID.randomUUID(),
// false,//isolatable
// null,//conflictResolver
// leafQueue,
// KeyBufferSerializer.INSTANCE,
// ByteArrayValueSerializer.INSTANCE,
// null // no record compressor
// );
/*
* verify the initial conditions - the root leaf is on the queue and
* its reference counter is one (1).
*/
final Leaf a = (Leaf)btree.getRoot();
assertEquals(1,a.referenceCount);
assertEquals(new PO[]{a}, leafQueue.toArray(new PO[0]));
/*
* touch the leaf. since we are scanning the queue, this does NOT cause
* another reference to the leaf to be added to the queue and the
* reference counter MUST NOT be incremented across the method call.
* Nothing is evicted and the leaf is not made persistent.
*/
btree.touch(a);
assertEquals(1,a.referenceCount);
assertEquals(new PO[]{a}, leafQueue.toArray(new PO[0]));
assertFalse(a.isPersistent());
}
/**
* Test verifies that touching a node when the queue is full and the node is
* the next reference to be evicted from the queue does NOT cause the node
* to be made persistent. The test is setup using a queue of capacity one
* (1) and NO scanning. The root leaf is already on the queue when the btree
* is created. The test verifies that merely touching the root leaf causes a
* reference to the leaf to be evicted from the queue, but does NOT cause
* the leaf to be made persistent. {@link BTree#touch(AbstractNode)} handles
* this condition by incrementing the reference counter before appending the
* node to the queue and therefore ensuring that the reference counter for
* the node that touched is not zero if the node is also selected for
* eviction. The test also verifies that the reference counter is correctly
* maintained across the touch. Since the counter was one before the touch
* and since the root was itself evicted, the counter after the touch is
* <code>1+1-1 = 1</code>.
*
* FIXME This test needs to use a tree with nodes and leaves or fake another
* root leaf since the minimum cache size is (2)
*/
public void test_touch03() {
/*
* setup the btree with a queue with surplus capacity and no scanning.
* The listener initially disallows any evictions and we have to
* explicitly notify the listener when it should expect an eviction.
*/
final int branchingFactor = 3;
final MyEvictionListener listener = new MyEvictionListener();
final int queueCapacity = 20;
final int queueScan = 0;
final MyHardReferenceQueue<PO> leafQueue = new MyHardReferenceQueue<PO>(
listener, queueCapacity, queueScan);
assertEquals(queueCapacity,leafQueue.capacity());
assertEquals(queueScan,leafQueue.nscan());
assertEquals(listener,leafQueue.getListener());
/*
* Setup the B+Tree directly so that we can override the hard reference
* queue.
*/
final BTree btree;
{
IRawStore store = new SimpleMemoryRawStore();
IndexMetadata metadata = new IndexMetadata(UUID.randomUUID());
metadata.setBranchingFactor(branchingFactor);
metadata.write(store);
Checkpoint checkpoint = metadata.firstCheckpoint();
checkpoint.write(store);
btree = new BTree(store, checkpoint, metadata, false/* readOnly */) {
@Override
protected HardReferenceQueue<PO> newWriteRetentionQueue(final boolean readOnly) {
return leafQueue;
}
};
}
// // The btree.
// final BTree btree = new BTree(
// new SimpleMemoryRawStore(),
// branchingFactor,
// UUID.randomUUID(),
// false,//isolatable
// null,//conflictResolver
// leafQueue,
// KeyBufferSerializer.INSTANCE,
// ByteArrayValueSerializer.INSTANCE,
// null // no record compressor
// );
/*
* verify the initial conditions - the root leaf is on the queue and
* its reference counter is one (1).
*/
final Leaf a = (Leaf)btree.getRoot();
assertEquals(1,a.referenceCount);
assertEquals(new PO[]{a}, leafQueue.toArray(new PO[0]));
assertFalse(a.isPersistent());
/*
* insert keys into the root and cause it to split.
*/
final SimpleEntry v3 = new SimpleEntry(3);
final SimpleEntry v5 = new SimpleEntry(5);
final SimpleEntry v7 = new SimpleEntry(7);
final SimpleEntry v9 = new SimpleEntry(9);
btree.insert(TestKeyBuilder.asSortKey(3),v3);
btree.insert(TestKeyBuilder.asSortKey(5),v5);
btree.insert(TestKeyBuilder.asSortKey(7),v7);
btree.insert(TestKeyBuilder.asSortKey(9),v9);
assertNotSame(a,btree.getRoot());
final Node c = (Node) btree.getRoot();
assertKeys(new int[]{7},c);
assertEquals(a,c.getChild(0));
final Leaf b = (Leaf) c.getChild(1);
assertKeys(new int[]{3,5},a);
assertValues(new Object[]{v3,v5}, a);
assertKeys(new int[]{7,9},b);
assertValues(new Object[]{v7,v9}, b);
/*
* bring the queue up to its capacity without causing it to overflow.
*/
while(leafQueue.size()<leafQueue.capacity()) {
// touch a node - which one does not really matter.
btree.touch(a);
}
/*
* examine the queue state and figure out which node or leaf we want to
* evict. we continue to append a specific node (a) until the reference
* that would be evicted next has a reference count of one (1). it does
* not matter which node this is. It will be either (b) or (c) depending
* on the code paths when we setup the test tree.
*/
AbstractNode ref;
while(true) {
ref = (AbstractNode) leafQueue.peek();
if(ref.referenceCount == 1 ) break;
listener.setExpectedRef(ref);
btree.touch(a);
}
/*
* touch the node or leaf that is poised for eviction from the queue and
* which would be made immutable if it were evicted since its
* pre-eviction reference count is one (1). since we are not scanning
* the queue, another reference to the node or leaf will be added to the
* queue. Since the queue is at capacity, the reference on the queue
* will be evicted. However, since the reference counter is non-zero in
* the eviction handler, the leaf will not be made persistent.
*/
assertEquals(1,ref.referenceCount);
listener.setExpectedRef(ref);
btree.touch(ref);
assertEquals(1,ref.referenceCount);
assertFalse(ref.isPersistent());
}
}