/**
* Atomic update.
*
* @return <code>null</code>
*/
@Override
protected Void doTask() throws Exception {
updateEvent.start();
try {
if (resourceManager.isOverflowAllowed()) throw new IllegalStateException();
final SegmentMetadata segmentMetadata = buildResult.segmentMetadata;
if (INFO) log.info("Begin: name=" + getOnlyResource() + ", newSegment=" + segmentMetadata);
/*
* Open the unisolated B+Tree on the live journal that is
* absorbing writes. We are going to update its index metadata.
*
* Note: I am using AbstractTask#getIndex(String name) so that
* the concurrency control logic will notice the changes to the
* BTree and cause it to be checkpointed if this task succeeds
* normally.
*/
final ILocalBTreeView view = (ILocalBTreeView) getIndex(getOnlyResource());
// make sure that this is the same scale-out index.
assertSameIndex(indexUUID, view.getMutableBTree());
if (view instanceof BTree) {
/*
* Note: there is an expectation that this is not a simple
* BTree because this the build task is supposed to be
* invoked after an overflow event, and that event should
* have re-defined the view to include the BTree on the new
* journal plus the historical view.
*
* One explanation for finding a simple view here is that
* the view was a simple BTree on the old journal and the
* data was copied from the old journal into the new journal
* and then someone decided to do a build even through a
* copy had already been done. However, this is not a very
* good explanation since we try to avoid doing a build if
* we have already done a copy!
*/
throw new RuntimeException(
"View is only a B+Tree: name="
+ buildResult.name
+ ", pmd="
+ view.getIndexMetadata().getPartitionMetadata());
}
// The live B+Tree.
final BTree btree = view.getMutableBTree();
if (INFO)
log.info(
"src="
+ getOnlyResource()
+ ",counter="
+ view.getCounter().get()
+ ",checkpoint="
+ btree.getCheckpoint());
assert btree != null : "Expecting index: " + getOnlyResource();
// clone the current metadata record for the live index.
final IndexMetadata indexMetadata = btree.getIndexMetadata().clone();
/*
* This is the index partition definition on the live index -
* the one that will be replaced with a new view as the result
* of this atomic update.
*/
final LocalPartitionMetadata currentpmd = indexMetadata.getPartitionMetadata();
// Check pre-conditions.
final IResourceMetadata[] currentResources = currentpmd.getResources();
{
if (currentpmd == null) {
throw new IllegalStateException("Not an index partition: " + getOnlyResource());
}
if (!currentResources[0].getUUID().equals(getJournal().getRootBlockView().getUUID())) {
throw new IllegalStateException(
"Expecting live journal to be the first resource: " + currentResources);
}
/*
* Note: I have commented out a bunch of pre-condition tests
* that are not valid for histories such as:
*
* history=create() register(0) split(0)
* copy(entryCount=314)
*
* This case arises when there are not enough index entries
* written on the journal after a split to warrant a build
* so the buffered writes are just copied to the new
* journal. The resources in the view are:
*
* 1. journal 2. segment
*
* And this update will replace the segment.
*/
// // the old journal's resource metadata.
// final IResourceMetadata oldJournalMetadata =
// oldResources[1];
// assert oldJournalMetadata != null;
// assert oldJournalMetadata instanceof JournalMetadata :
// "name="
// + getOnlyResource() + ", old pmd=" + oldpmd
// + ", segmentMetadata=" + buildResult.segmentMetadata;
//
// // live journal must be newer.
// assert journal.getRootBlockView().getCreateTime() >
// oldJournalMetadata
// .getCreateTime();
// new index segment build from a view that did not include
// data from the live journal.
assert segmentMetadata.getCreateTime()
< getJournal().getRootBlockView().getFirstCommitTime()
: "segment createTime LT journal 1st commit time"
+ ": segmentMetadata="
+ segmentMetadata
+ ", journal: "
+ getJournal().getRootBlockView();
// if (oldResources.length == 3) {
//
// // the old index segment's resource metadata.
// final IResourceMetadata oldSegmentMetadata =
// oldResources[2];
// assert oldSegmentMetadata != null;
// assert oldSegmentMetadata instanceof SegmentMetadata;
//
// assert oldSegmentMetadata.getCreateTime() <=
// oldJournalMetadata
// .getCreateTime();
//
// }
}
// new view definition.
final IResourceMetadata[] newResources =
new IResourceMetadata[] {
// the live journal.
getJournal().getResourceMetadata(),
// the newly built index segment.
segmentMetadata
};
// describe the index partition.
indexMetadata.setPartitionMetadata(
new LocalPartitionMetadata( //
currentpmd.getPartitionId(), //
currentpmd.getSourcePartitionId(), //
currentpmd.getLeftSeparatorKey(), //
currentpmd.getRightSeparatorKey(), //
newResources, //
currentpmd.getIndexPartitionCause()
// currentpmd.getHistory()
// + OverflowActionEnum.Merge//
// + "(lastCommitTime="
// + segmentMetadata.getCreateTime()//
// + ",btreeEntryCount="
// + btree.getEntryCount()//
// + ",segmentEntryCount="
// + buildResult.builder.getCheckpoint().nentries//
// + ",segment="
// + segmentMetadata.getUUID()//
// + ",counter="
// + btree.getCounter().get()//
// + ",oldResources="
// + Arrays.toString(currentResources) + ") "
));
// update the metadata associated with the btree
btree.setIndexMetadata(indexMetadata);
if (INFO)
log.info(
"Updated view: name="
+ getOnlyResource()
+ ", pmd="
+ indexMetadata.getPartitionMetadata());
/*
* Verify that the btree recognizes that it needs to be
* checkpointed.
*
* Note: The atomic commit point is when this task commits.
*/
assert btree.needsCheckpoint();
// btree.writeCheckpoint();
// {
// final long id0 = btree.getCounter().get();
// final long pid = id0 >> 32;
// final long mask = 0xffffffffL;
// final int ctr = (int) (id0 & mask);
// log.warn("name="+getOnlyResource()+", counter="+id0+", pid="+pid+",
// ctr="+ctr);
// }
// notify successful index partition build.
resourceManager.overflowCounters.indexPartitionMergeCounter.incrementAndGet();
return null;
} finally {
updateEvent.end();
}
} // doTask()
/**
* Test correct detection and resolution of a write-write conflict. An index is registered with an
* {@link IConflictResolver} and the journal is committed. Two transactions (tx1, tx2) are then
* started. Both transactions write a value under the same key. tx1 prepares and commits. tx2
* attempts to prepare, and the test verifies that the conflict resolver is invoked, that it may
* resolve the conflict causing validation to succeed and that the value determined by conflict
* resolution is made persistent when tx2 commits.
*/
public void test_writeWriteConflict_conflictIsResolved() {
final Journal journal = new Journal(getProperties());
try {
final String name = "abc";
final byte[] k1 = new byte[] {1};
final byte[] v1a = new byte[] {1};
final byte[] v1b = new byte[] {2};
final byte[] v1c = new byte[] {3};
{
/*
* register an index with a conflict resolver and commit the
* journal.
*/
final IndexMetadata metadata = new IndexMetadata(name, UUID.randomUUID());
metadata.setIsolatable(true);
metadata.setConflictResolver(new SingleValueConflictResolver(k1, v1c));
journal.registerIndex(name, BTree.create(journal, metadata));
journal.commit();
}
/*
* Create two transactions.
*/
final long tx1 = journal.newTx(ITx.UNISOLATED);
final long tx2 = journal.newTx(ITx.UNISOLATED);
/*
* Write a value under the same key on the same index in both
* transactions.
*/
journal.getIndex(name, tx1).insert(k1, v1a);
journal.getIndex(name, tx2).insert(k1, v1b);
journal.commit(tx1);
/*
* verify that the value from tx1 is found under the key on the
* unisolated index.
*/
assertEquals(v1a, (byte[]) journal.getIndex(name).lookup(k1));
journal.commit(tx2);
/*
* verify that the resolved value is found under the key on the
* unisolated index.
*/
assertEquals(v1c, (byte[]) journal.getIndex(name).lookup(k1));
} finally {
journal.destroy();
}
}
/**
* Test generates an {@link IndexSegment} from a (typically historical) fused view of an index
* partition. The resulting {@link IndexSegment} is a complete replacement for the historical view
* but does not possess any deleted index entries. Typically the {@link IndexSegment} will be used
* to replace the current index partition definition such that the resources that were the inputs
* to the view from which the {@link IndexSegment} was built are no longer required to read on
* that view. This change needs to be recorded in the {@link MetadataIndex} before clients will
* being reading from the new view using the new {@link IndexSegment}.
*
* @throws IOException
* @throws ExecutionException
* @throws InterruptedException
* @todo test more complex merges.
*/
public void test_mergeWithOverflow()
throws IOException, InterruptedException, ExecutionException {
/*
* Register the index.
*/
final String name = "testIndex";
final UUID indexUUID = UUID.randomUUID();
final IndexMetadata indexMetadata = new IndexMetadata(name, indexUUID);
{
// must support delete markers
indexMetadata.setDeleteMarkers(true);
// must be an index partition.
indexMetadata.setPartitionMetadata(
new LocalPartitionMetadata(
0, // partitionId.
-1, // not a move.
new byte[] {}, // leftSeparator
null, // rightSeparator
new IResourceMetadata[] { //
resourceManager.getLiveJournal().getResourceMetadata(), //
}, //
IndexPartitionCause.register(resourceManager)
// ,"" // history
));
// submit task to register the index and wait for it to complete.
concurrencyManager
.submit(new RegisterIndexTask(concurrencyManager, name, indexMetadata))
.get();
}
/*
* Populate the index with some data.
*/
final BTree groundTruth =
BTree.create(new SimpleMemoryRawStore(), new IndexMetadata(indexUUID));
{
final int nentries = 10;
final byte[][] keys = new byte[nentries][];
final byte[][] vals = new byte[nentries][];
final Random r = new Random();
for (int i = 0; i < nentries; i++) {
keys[i] = TestKeyBuilder.asSortKey(i);
vals[i] = new byte[4];
r.nextBytes(vals[i]);
groundTruth.insert(keys[i], vals[i]);
}
final IIndexProcedure proc =
BatchInsertConstructor.RETURN_NO_VALUES.newInstance(
indexMetadata, 0 /* fromIndex */, nentries /*toIndex*/, keys, vals);
// submit the task and wait for it to complete.
concurrencyManager
.submit(new IndexProcedureTask(concurrencyManager, ITx.UNISOLATED, name, proc))
.get();
}
/*
* Force overflow causing an empty btree to be created for that index on
* a new journal and the view definition in the new btree to be updated.
*/
// createTime of the old journal.
final long createTime0 = resourceManager.getLiveJournal().getRootBlockView().getCreateTime();
// uuid of the old journal.
final UUID uuid0 = resourceManager.getLiveJournal().getRootBlockView().getUUID();
// force overflow onto a new journal.
final OverflowMetadata overflowMetadata = resourceManager.doSynchronousOverflow();
// nothing should have been copied to the new journal.
assertEquals(0, overflowMetadata.getActionCount(OverflowActionEnum.Copy));
// lookup the old journal again using its createTime.
final AbstractJournal oldJournal = resourceManager.getJournal(createTime0);
assertEquals("uuid", uuid0, oldJournal.getRootBlockView().getUUID());
assertNotSame("closeTime", 0L, oldJournal.getRootBlockView().getCloseTime());
// run merge task.
final BuildResult result;
{
/*
* Note: The task start time is a historical read on the final
* committed state of the old journal. This means that the generated
* index segment will have a createTime EQ to the lastCommitTime on
* the old journal. This also means that it will have been generated
* from a fused view of all data as of the final commit state of the
* old journal.
*/
// final OverflowMetadata omd = new OverflowMetadata(resourceManager);
final ViewMetadata vmd = overflowMetadata.getViewMetadata(name);
// task to run.
final CompactingMergeTask task = new CompactingMergeTask(vmd);
try {
// overflow must be disallowed as a task pre-condition.
resourceManager.overflowAllowed.compareAndSet(true, false);
/*
* Submit task and await result (metadata describing the new
* index segment).
*/
result = concurrencyManager.submit(task).get();
} finally {
// re-enable overflow processing.
resourceManager.overflowAllowed.set(true);
}
final IResourceMetadata segmentMetadata = result.segmentMetadata;
if (log.isInfoEnabled()) log.info(segmentMetadata.toString());
// verify index segment can be opened.
resourceManager.openStore(segmentMetadata.getUUID());
// Note: this assertion only works if we store the file path vs its basename.
// assertTrue(new File(segmentMetadata.getFile()).exists());
// verify createTime == lastCommitTime on the old journal.
assertEquals(
"createTime",
oldJournal.getRootBlockView().getLastCommitTime(),
segmentMetadata.getCreateTime());
// verify segment has all data in the groundTruth btree.
{
final IndexSegmentStore segStore =
(IndexSegmentStore) resourceManager.openStore(segmentMetadata.getUUID());
final IndexSegment seg = segStore.loadIndexSegment();
AbstractBTreeTestCase.assertSameBTree(groundTruth, seg);
}
}
/*
* verify same data from ground truth and the new view (using btree
* helper classes for this).
*/
{
final IIndex actual = resourceManager.getIndex(name, ITx.UNISOLATED);
AbstractBTreeTestCase.assertSameBTree(groundTruth, actual);
}
}
/**
* Test correct detection of a write-write conflict. An index is registered and the journal is
* committed. Two transactions (tx1, tx2) are then started. Both transactions write a value under
* the same key. tx1 prepares and commits. tx2 attempts to prepare, and the test verifies that a
* {@link ValidationError} is reported.
*/
public void test_writeWriteConflict_correctDetection() {
final Journal journal = new Journal(getProperties());
try {
String name = "abc";
final byte[] k1 = new byte[] {1};
final byte[] v1a = new byte[] {1};
final byte[] v1b = new byte[] {2};
{
/*
* register an index and commit the journal.
*/
IndexMetadata metadata = new IndexMetadata(name, UUID.randomUUID());
metadata.setIsolatable(true);
// Note: No conflict resolver.
journal.registerIndex(name, BTree.create(journal, metadata));
journal.commit();
}
/*
* Create two transactions.
*/
final long tx1 = journal.newTx(ITx.UNISOLATED);
final long tx2 = journal.newTx(ITx.UNISOLATED);
/*
* Write a value under the same key on the same index in both
* transactions.
*/
journal.getIndex(name, tx1).insert(k1, v1a);
journal.getIndex(name, tx2).insert(k1, v1b);
journal.commit(tx1);
/*
* verify that the value from tx1 is found under the key on the
* unisolated index.
*/
assertEquals(v1a, (byte[]) journal.getIndex(name).lookup(k1));
// final ITx tmp = journal.getTx(tx2);
try {
journal.commit(tx2);
fail("Expecting: " + ValidationError.class);
} catch (ValidationError ex) {
if (log.isInfoEnabled()) log.info("Ignoring expected exception: " + ex);
// assertTrue(tmp.isAborted());
}
} finally {
journal.destroy();
}
}