/**
* 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()
