try
{
Tracing.trace("Merging memtable contents");
for (Memtable memtable : view.memtables)
{
OnDiskAtomIterator iter = filter.getMemtableColumnIterator(memtable);
if (iter != null)
{
iterators.add(iter);
temp.delete(iter.getColumnFamily());
while (iter.hasNext())
temp.addAtom(iter.next());
}
container.addAll(temp, HeapAllocator.instance);
temp.clear();
}
// avoid changing the filter columns of the original filter
// (reduceNameFilter removes columns that are known to be irrelevant)
NamesQueryFilter namesFilter = (NamesQueryFilter) filter.filter;
TreeSet<ByteBuffer> filterColumns = new TreeSet<ByteBuffer>(namesFilter.columns);
QueryFilter reducedFilter = new QueryFilter(filter.key, filter.path, namesFilter.withUpdatedColumns(filterColumns));
/* add the SSTables on disk */
Collections.sort(view.sstables, SSTable.maxTimestampComparator);
// read sorted sstables
long mostRecentRowTombstone = Long.MIN_VALUE;
for (SSTableReader sstable : view.sstables)
{
// if we've already seen a row tombstone with a timestamp greater
// than the most recent update to this sstable, we're done, since the rest of the sstables
// will also be older
if (sstable.getMaxTimestamp() < mostRecentRowTombstone)
break;
long currentMaxTs = sstable.getMaxTimestamp();
reduceNameFilter(reducedFilter, container, currentMaxTs);
if (((NamesQueryFilter) reducedFilter.filter).columns.isEmpty())
break;
OnDiskAtomIterator iter = reducedFilter.getSSTableColumnIterator(sstable);
iterators.add(iter);
if (iter.getColumnFamily() != null)
{
ColumnFamily cf = iter.getColumnFamily();
if (cf.isMarkedForDelete())
{
// track the most recent row level tombstone we encounter
mostRecentRowTombstone = cf.deletionInfo().getTopLevelDeletion().markedForDeleteAt;
}
temp.delete(cf);
sstablesIterated++;
Tracing.trace("Merging data from sstable {}", sstable.descriptor.generation);
while (iter.hasNext())
temp.addAtom(iter.next());
}
container.addAll(temp, HeapAllocator.instance);
temp.clear();
}
// we need to distinguish between "there is no data at all for this row" (BF will let us rebuild that efficiently)
// and "there used to be data, but it's gone now" (we should cache the empty CF so we don't need to rebuild that slower)
if (iterators.isEmpty())
return null;
// do a final collate. toCollate is boilerplate required to provide a CloseableIterator
final ColumnFamily c2 = container;
CloseableIterator<OnDiskAtom> toCollate = new SimpleAbstractColumnIterator()
{
final Iterator<IColumn> iter = c2.iterator();
protected OnDiskAtom computeNext()
{
return iter.hasNext() ? iter.next() : endOfData();
}
public ColumnFamily getColumnFamily()
{
return c2;