private Integer seekToSubColumn(
CFMetaData metadata,
FileDataInput file,
ByteBuffer sblockId,
List<IndexHelper.IndexInfo> indexList)
throws IOException {
file.readInt(); // column count
/* get the various column ranges we have to read */
AbstractType comparator = metadata.comparator;
int index = IndexHelper.indexFor(sblockId, indexList, comparator, false);
if (index == indexList.size()) return null;
IndexHelper.IndexInfo indexInfo = indexList.get(index);
if (comparator.compare(sblockId, indexInfo.firstName) < 0) return null;
FileMark mark = file.mark();
FileUtils.skipBytesFully(file, indexInfo.offset);
while (file.bytesPastMark(mark) < indexInfo.offset + indexInfo.width) {
Integer dataLength = isSubBlockFound(metadata, file, sblockId);
if (dataLength == null) return null;
if (dataLength < 0) continue;
return dataLength;
}
return null;
}
/**
* Checks if the current column is the one we are looking for
*
* @param metadata
* @param file
* @param sblockId
* @return if > 0 the length to read from current file offset. if -1 not relevent. if null out of
* bounds
*/
private Integer isSubBlockFound(CFMetaData metadata, FileDataInput file, ByteBuffer sblockId)
throws IOException {
ByteBuffer name = ByteBufferUtil.readWithShortLength(file);
// Stop if we've gone too far (return null)
if (metadata.comparator.compare(name, sblockId) > 0) return null;
// verify column type;
int b = file.readUnsignedByte();
// skip ts (since we know block ids are unique)
long ts = file.readLong();
int sblockLength = file.readInt();
if (!name.equals(sblockId)
|| (b & ColumnSerializer.DELETION_MASK) != 0
|| (b & ColumnSerializer.EXPIRATION_MASK) != 0) {
FileUtils.skipBytesFully(file, sblockLength);
return -1;
}
return sblockLength;
}
/**
* Retrieves a local subBlock
*
* @param blockId row key
* @param sblockId SubBlock column name
* @param offset inside the sblock
* @return a local sublock
* @throws TException
*/
private LocalBlock getLocalSubBlock(
String subBlockCFName, ByteBuffer blockId, ByteBuffer sblockId, int offset)
throws TException {
DecoratedKey<Token<?>> decoratedKey =
new DecoratedKey<Token<?>>(StorageService.getPartitioner().getToken(blockId), blockId);
Table table = Table.open(cfsKeyspace);
ColumnFamilyStore sblockStore = table.getColumnFamilyStore(subBlockCFName);
Collection<SSTableReader> sstables = sblockStore.getSSTables();
for (SSTableReader sstable : sstables) {
long position = sstable.getPosition(decoratedKey, Operator.EQ);
if (position == -1) continue;
String filename = sstable.descriptor.filenameFor(Component.DATA);
RandomAccessFile raf = null;
int mappedLength = -1;
MappedByteBuffer mappedData = null;
MappedFileDataInput file = null;
try {
raf = new RandomAccessFile(filename, "r");
assert position < raf.length();
mappedLength =
(raf.length() - position) < Integer.MAX_VALUE
? (int) (raf.length() - position)
: Integer.MAX_VALUE;
mappedData = raf.getChannel().map(FileChannel.MapMode.READ_ONLY, position, mappedLength);
file = new MappedFileDataInput(mappedData, filename, 0);
if (file == null) continue;
// Verify key was found in data file
DecoratedKey keyInDisk =
SSTableReader.decodeKey(
sstable.partitioner, sstable.descriptor, ByteBufferUtil.readWithShortLength(file));
assert keyInDisk.equals(decoratedKey)
: String.format("%s != %s in %s", keyInDisk, decoratedKey, file.getPath());
long rowSize = SSTableReader.readRowSize(file, sstable.descriptor);
assert rowSize > 0;
assert rowSize < mappedLength;
Filter bf = IndexHelper.defreezeBloomFilter(file, sstable.descriptor.usesOldBloomFilter);
// verify this column in in this version of the row.
if (!bf.isPresent(sblockId)) continue;
List<IndexHelper.IndexInfo> indexList = IndexHelper.deserializeIndex(file);
// we can stop early if bloom filter says none of the
// columns actually exist -- but,
// we can't stop before initializing the cf above, in
// case there's a relevant tombstone
ColumnFamilySerializer serializer = ColumnFamily.serializer();
try {
ColumnFamily cf =
serializer.deserializeFromSSTableNoColumns(
ColumnFamily.create(sstable.metadata), file);
if (cf.isMarkedForDelete()) continue;
} catch (Exception e) {
e.printStackTrace();
throw new IOException(
serializer
+ " failed to deserialize "
+ sstable.getColumnFamilyName()
+ " with "
+ sstable.metadata
+ " from "
+ file,
e);
}
Integer sblockLength = null;
if (indexList == null) sblockLength = seekToSubColumn(sstable.metadata, file, sblockId);
else sblockLength = seekToSubColumn(sstable.metadata, file, sblockId, indexList);
if (sblockLength == null || sblockLength < 0) continue;
int bytesReadFromStart = mappedLength - (int) file.bytesRemaining();
if (logger.isDebugEnabled())
logger.debug("BlockLength = " + sblockLength + " Availible " + file.bytesRemaining());
assert offset <= sblockLength : String.format("%d > %d", offset, sblockLength);
long dataOffset = position + bytesReadFromStart;
if (file.bytesRemaining() == 0 || sblockLength == 0) continue;
return new LocalBlock(file.getPath(), dataOffset + offset, sblockLength - offset);
} catch (IOException e) {
throw new TException(e);
} finally {
FileUtils.closeQuietly(raf);
}
}
return null;
}
