本文整理汇总了Java中org.apache.cassandra.io.sstable.SSTableScanner.seekTo方法的典型用法代码示例。如果您正苦于以下问题：Java SSTableScanner.seekTo方法的具体用法？Java SSTableScanner.seekTo怎么用？Java SSTableScanner.seekTo使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类org.apache.cassandra.io.sstable.SSTableScanner的用法示例。
在下文中一共展示了SSTableScanner.seekTo方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: getIterator
import org.apache.cassandra.io.sstable.SSTableScanner; //导入方法依赖的package包/类
/**
* Get a row iterator over the provided memtables and sstables, between the provided keys
* and filtered by the queryfilter.
* @param memtables Memtables pending flush.
* @param sstables SStables to scan through.
* @param startWith Start at this key
* @param stopAt Stop and this key
* @param filter Used to decide which columns to pull out
* @param cfs
* @return A row iterator following all the given restrictions
*/
public static CloseableIterator<Row> getIterator(final Iterable<Memtable> memtables,
final Collection<SSTableReader> sstables,
final RowPosition startWith,
final RowPosition stopAt,
final QueryFilter filter,
final ColumnFamilyStore cfs)
{
// fetch data from current memtable, historical memtables, and SSTables in the correct order.
final List<CloseableIterator<OnDiskAtomIterator>> iterators = new ArrayList<CloseableIterator<OnDiskAtomIterator>>();
// memtables
for (Memtable memtable : memtables)
{
iterators.add(new ConvertToColumnIterator(filter, memtable.getEntryIterator(startWith, stopAt)));
}
for (SSTableReader sstable : sstables)
{
final SSTableScanner scanner = sstable.getScanner(filter);
scanner.seekTo(startWith);
iterators.add(scanner);
}
// reduce rows from all sources into a single row
return MergeIterator.get(iterators, COMPARE_BY_KEY, new MergeIterator.Reducer<OnDiskAtomIterator, Row>()
{
private final int gcBefore = (int) (System.currentTimeMillis() / 1000) - cfs.metadata.getGcGraceSeconds();
private final List<OnDiskAtomIterator> colIters = new ArrayList<OnDiskAtomIterator>();
private DecoratedKey key;
private ColumnFamily returnCF;
@Override
protected void onKeyChange()
{
this.returnCF = ColumnFamily.create(cfs.metadata);
}
public void reduce(OnDiskAtomIterator current)
{
this.colIters.add(current);
this.key = current.getKey();
this.returnCF.delete(current.getColumnFamily());
}
protected Row getReduced()
{
// First check if this row is in the rowCache. If it is we can skip the rest
ColumnFamily cached = cfs.getRawCachedRow(key);
if (cached == null)
{
// not cached: collate
filter.collateOnDiskAtom(returnCF, colIters, gcBefore);
}
else
{
QueryFilter keyFilter = new QueryFilter(key, filter.path, filter.filter);
returnCF = cfs.filterColumnFamily(cached, keyFilter, gcBefore);
}
Row rv = new Row(key, returnCF);
colIters.clear();
key = null;
return rv;
}
});
}