Package org.apache.cassandra.io.sstable.format.bti

Class RowIndexReader

java.lang.Object

org.apache.cassandra.io.tries.Walker<RowIndexReader>

org.apache.cassandra.io.sstable.format.bti.RowIndexReader

All Implemented Interfaces:

AutoCloseable

@NotThreadSafe
public class RowIndexReader
extends Walker<RowIndexReader>

Reader class for row index files created by RowIndexWriter.

Row index "tries" do not need to store whole keys, as what we need from them is to be able to tell where in the data file to start looking for a given key. Instead, we store some prefix that is greater than the greatest key of the previous index section and smaller than or equal to the smallest key of the next. So for a given key the first index section that could potentially contain it is given by the trie's floor for that key.

This builds upon the trie Walker class which provides basic trie walking functionality. The class is thread-unsafe and must be re-instantiated for every thread that needs access to the trie (its overhead is below that of a RandomAccessReader).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RowIndexReader.IndexInfo

Nested classes/interfaces inherited from class org.apache.cassandra.io.tries.Walker

Walker.Extractor<RESULT,VALUE>, Walker.PayloadToString, Walker.TransitionBytesCollector

Field Summary

Fields

Modifier and Type	Field	Description
final Version	version

Fields inherited from class org.apache.cassandra.io.tries.Walker

buf, BYTE_COMPARABLE_VERSION, greaterBranch, lesserBranch, nodeType, NONE, position, root

Constructor Summary

Constructors

Constructor	Description
RowIndexReader(FileHandle file, long root, Version version)
RowIndexReader(FileHandle file, org.apache.cassandra.io.sstable.format.bti.TrieIndexEntry entry, Version version)

Method Summary

Modifier and Type	Method	Description
void	dumpTrie(PrintStream out)
protected RowIndexReader.IndexInfo	getCurrentIndexInfo()
RowIndexReader.IndexInfo	min()
protected RowIndexReader.IndexInfo	readPayload(int ppos, int bits)
RowIndexReader.IndexInfo	separatorFloor(ByteComparable key)	Computes the floor for a given key.

Methods inherited from class org.apache.cassandra.io.tries.Walker

close, dumpTrie, follow, followWithGreater, followWithLesser, getMaxTerm, getMinTerm, go, goMax, goMin, greaterTransition, hasChildren, hasPayload, lastTransition, lesserTransition, nodeSize, nodeTypeOrdinal, payloadFlags, payloadPosition, prefix, prefixAndNeighbours, search, toString, transition, transitionByte, transitionRange

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

version

public final Version version

Constructor Details

RowIndexReader

public RowIndexReader(FileHandle file,
 long root,
 Version version)

RowIndexReader

public RowIndexReader(FileHandle file,
 org.apache.cassandra.io.sstable.format.bti.TrieIndexEntry entry,
 Version version)

Method Details

separatorFloor

public RowIndexReader.IndexInfo separatorFloor(ByteComparable key)
                                        throws IOException

Computes the floor for a given key.

Throws:

IOException

min

public RowIndexReader.IndexInfo min()
                             throws IOException

Throws:

IOException

getCurrentIndexInfo

protected RowIndexReader.IndexInfo getCurrentIndexInfo()
                                                throws IOException

Throws:

IOException

readPayload

protected RowIndexReader.IndexInfo readPayload(int ppos,
 int bits)
                                        throws IOException

Throws:

IOException

dumpTrie

public void dumpTrie(PrintStream out)
              throws IOException

Throws:

IOException