/*
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 15, 2008
*/
package com.bigdata.btree;
import java.lang.ref.WeakReference;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.UUID;
import com.bigdata.btree.AbstractBTree.HardReference;
import com.bigdata.btree.keys.TestKeyBuilder;
import com.bigdata.rawstore.IRawStore;
import com.bigdata.rawstore.SimpleMemoryRawStore;
/**
* Unit tests for transient {@link BTree}s (no backing store).
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class TestTransientBTree extends AbstractBTreeTestCase {
public TestTransientBTree() {
super();
}
public TestTransientBTree(String name) {
super(name);
}
/**
* Test the ability to create a transient {@link BTree} (one not backed by a
* persistence store).
*/
public void test_createTransient() {
final BTree btree = BTree.createTransient(new IndexMetadata(UUID
.randomUUID()));
assertNotNull(btree);
assertNull(btree.getStore());
assertEquals(0, btree.getEntryCount());
assertNotNull(btree.getRoot());
final String expected = "def";
btree.insert("abc", expected);
assertEquals(expected,(String)btree.lookup("abc"));
assertTrue(btree.getRoot().self instanceof HardReference<?>);
}
/**
* Verifies that closing a transient {@link BTree} is allowed and that
* all data is discarded.
*/
public void test_close() {
final BTree btree = BTree.createTransient(new IndexMetadata(UUID
.randomUUID()));
assertEquals(0,btree.getEntryCount());
btree.insert("abc", "def");
assertEquals(1, btree.getEntryCount());
btree.close();
// force re-open.
btree.reopen();
assertEquals(0, btree.getEntryCount());
}
/**
* Test inserts a bunch of data into a transient {@link BTree} and verifies
* that eviction of dirty nodes and leaves does not result in errors arising
* from an attempt to persist their state on the (non-existent) backing
* store.
*/
public void test_eviction() {
final IndexMetadata md = new IndexMetadata(UUID.randomUUID());
final int branchingFactor = 3;
md.setBranchingFactor(branchingFactor);
final BTree btree = BTree.createTransient(md);
final int writeRetentionQueueCapacity = btree.writeRetentionQueue
.capacity();
if (log.isInfoEnabled())
log.info(btree.toString());
/*
* Until the write retention queue is full.
*/
long key = 0L;
while (btree.writeRetentionQueue.size() < writeRetentionQueueCapacity) {
btree.insert(key, key * 2);
key++;
}
if (log.isInfoEnabled())
log.info(btree.toString());
// insert several more leaves worth of data into the btree.
for (int i = 0; i < branchingFactor * 10; i++) {
btree.insert(key, key * 2);
key++;
}
if (log.isInfoEnabled())
log.info(btree.toString());
/*
* no errors!
*/
}
/**
* Test verifies that the nodes and leaves become weakly reachable once they
* have been deleted.
* <p>
* The test builds up a modest amount of data in the {@link BTree} using a
* small branching factor to force a large #of nodes and leaves to be
* created. A traversal is then performed of the nodes and leaves and all of
* their references are placed into a weak value collection. It then removes
* all entries in a key range, which should cause some leaves (and perhaps
* some nodes) to become weakly reachable. Finally, it forces a large number
* of object allocations in order to prompt a GC that will clear those weak
* references. The weak reference collection is then scanned to verify that
* its size has been decreased.
* <p>
* Note: This test is of necessity subject to the whims of the garbage
* collector. If it fails, try increasing some of the constants in the test
* and see if that will provoke a GC that will clear the references.
*/
public void test_delete() {
final IndexMetadata md = new IndexMetadata(UUID.randomUUID());
final int branchingFactor = 3;
md.setBranchingFactor(branchingFactor);
final BTree btree = BTree.createTransient(md);
if (log.isInfoEnabled())
log.info(btree.toString());
/*
* Until the write retention queue is full.
*/
long key = 0L;
while (key < 100000) {
btree.insert(key, key * 2);
key++;
}
if (log.isInfoEnabled())
log.info(btree.toString());
/*
* Populate a weak value collection from the BTree's nodes and leaves.
*/
final LinkedList<WeakReference<AbstractNode>> refs = new LinkedList<WeakReference<AbstractNode>>();
{
final Iterator<AbstractNode> itr = btree.getRoot().postOrderNodeIterator();
while(itr.hasNext()) {
final AbstractNode node = itr.next();
refs.add( new WeakReference(node) );
}
if (log.isInfoEnabled())
log.info("There are " + refs.size() + " nodes in the btree");
if (log.isInfoEnabled())
log.info("after inserting keys: " + btree.toString());
assertEquals(btree.getNodeCount()+btree.getLeafCount(),refs.size());
}
/*
* Now delete a key-range and verify that #of nodes in the btree has
* been decreased.
*/
{
final ITupleIterator itr = btree.rangeIterator(TestKeyBuilder
.asSortKey(10000L), TestKeyBuilder.asSortKey(20000L),
0/* capacity */, IRangeQuery.DEFAULT | IRangeQuery.CURSOR,
null/* filter */);
while(itr.hasNext()) {
itr.next();
itr.remove();
}
if (log.isInfoEnabled())
log.info("after deleting key range: " + btree.toString());
assertTrue(btree.getNodeCount() + btree.getLeafCount() < refs
.size());
}
/*
* Loop until GC activity has caused references to be cleared.
*/
final int limit = 100;
for (int x = 0; x < limit; x++) {
System.gc();
final int n = countClearedRefs(refs);
if (log.isInfoEnabled())
log.info("pass " + x + "of " + limit
+ ": #of cleared references=" + n);
if (n <= refs.size()) {
return;
}
final List<byte[]> stuff = new LinkedList<byte[]>();
for (int y = 0; y < 1000; y++) {
stuff.add(new byte[y * 1000 + 1]);
}
}
fail("Did not clear references after "+limit+" passes");
}
/**
* Return the #of entries in the collection whose references have been
* cleared.
*
* @param refs
*
* @param <T>
*
* @return
*/
private <T> int countClearedRefs(List<WeakReference<T>> refs) {
final Iterator<WeakReference<T>> itr = refs.iterator();
int n = 0;
while(itr.hasNext()) {
final WeakReference<T> ref = itr.next();
if(ref.get()==null) n++;
}
return n;
}
/**
* Tests various methods that deal with persistence and makes sure that we
* have reasonable error messages.
*/
public void test_niceErrors() {
final BTree btree = BTree.createTransient(new IndexMetadata(UUID
.randomUUID()));
try {
btree.handleCommit(System.currentTimeMillis());
} catch (UnsupportedOperationException ex) {
if(log.isInfoEnabled())
log.info("Ignoring expected exception: " + ex);
}
// try {
// btree.flush();
// } catch (UnsupportedOperationException ex) {
// log.info("Ignoring expected exception: " + ex);
// }
try {
btree.writeCheckpoint();
} catch (UnsupportedOperationException ex) {
if(log.isInfoEnabled())
log.info("Ignoring expected exception: " + ex);
}
}
/**
* This is the same as {@link #test_delete()} but the {@link BTree} is
* backed by an {@link IRawStore}.
*
* @todo since the code is identical other than allocating the {@link BTree}
* , factor out a doDeleteTest(BTree) method.
*/
public void test_deletePersistent() {
final IndexMetadata md = new IndexMetadata(UUID.randomUUID());
final int branchingFactor = 3;
md.setBranchingFactor(branchingFactor);
final BTree btree = BTree.create(new SimpleMemoryRawStore(), md);
if (log.isInfoEnabled())
log.info(btree.toString());
/*
* Until the write retention queue is full.
*/
long key = 0L;
while (key < 100000) {
btree.insert(key, key * 2);
key++;
}
if (log.isInfoEnabled())
log.info(btree.toString());
/*
* Populate a weak value collection from the BTree's nodes and leaves.
*/
final LinkedList<WeakReference<AbstractNode>> refs = new LinkedList<WeakReference<AbstractNode>>();
{
final Iterator<AbstractNode> itr = btree.getRoot().postOrderNodeIterator();
while(itr.hasNext()) {
final AbstractNode node = itr.next();
refs.add( new WeakReference(node) );
}
if (log.isInfoEnabled())
log.info("There are " + refs.size() + " nodes in the btree");
if (log.isInfoEnabled())
log.info("after inserting keys: " + btree.toString());
assertEquals(btree.getNodeCount()+btree.getLeafCount(),refs.size());
}
/*
* Now delete a key-range and verify that #of nodes in the btree has
* been decreased.
*/
{
final ITupleIterator itr = btree.rangeIterator(TestKeyBuilder
.asSortKey(10000L), TestKeyBuilder.asSortKey(20000L),
0/* capacity */, IRangeQuery.DEFAULT | IRangeQuery.CURSOR,
null/* filter */);
while(itr.hasNext()) {
itr.next();
itr.remove();
}
if (log.isInfoEnabled())
log.info("after deleting key range: " + btree.toString());
assertTrue(btree.getNodeCount() + btree.getLeafCount() < refs
.size());
}
/*
* Loop until GC activity has caused references to be cleared.
*/
final int limit = 100;
for (int x = 0; x < limit; x++) {
System.gc();
final int n = countClearedRefs(refs);
if (log.isInfoEnabled())
log.info("pass " + x + "of " + limit
+ ": #of cleared references=" + n);
if (n <= refs.size()) {
return;
}
final List<byte[]> stuff = new LinkedList<byte[]>();
for (int y = 0; y < 1000; y++) {
stuff.add(new byte[y * 1000 + 1]);
}
}
fail("Did not clear references after : " + limit + " passes");
}
}