ReplayPosition rp = ReplayPosition.getReplayPosition(cfs.getSSTables());
cfPositions.put(cfs.metadata.cfId, rp);
}
final ReplayPosition globalPosition = Ordering.from(ReplayPosition.comparator).min(cfPositions.values());
Checksum checksum = new CRC32();
for (final File file : clogs)
{
logger.info("Replaying " + file.getPath());
final long segment = CommitLogSegment.idFromFilename(file.getName());
RandomAccessReader reader = RandomAccessReader.open(new File(file.getAbsolutePath()), true);
assert reader.length() <= Integer.MAX_VALUE;
try
{
int replayPosition;
if (globalPosition.segment < segment)
replayPosition = 0;
else if (globalPosition.segment == segment)
replayPosition = globalPosition.position;
else
replayPosition = (int) reader.length();
if (replayPosition < 0 || replayPosition >= reader.length())
{
// replayPosition > reader.length() can happen if some data gets flushed before it is written to the commitlog
// (see https://issues.apache.org/jira/browse/CASSANDRA-2285)
logger.debug("skipping replay of fully-flushed {}", file);
continue;
}
reader.seek(replayPosition);
if (logger.isDebugEnabled())
logger.debug("Replaying " + file + " starting at " + reader.getFilePointer());
/* read the logs populate RowMutation and apply */
while (!reader.isEOF())
{
if (logger.isDebugEnabled())
logger.debug("Reading mutation at " + reader.getFilePointer());
long claimedCRC32;
int serializedSize;
try
{
// any of the reads may hit EOF
serializedSize = reader.readInt();
if (serializedSize == CommitLog.END_OF_SEGMENT_MARKER)
{
logger.debug("Encountered end of segment marker at " + reader.getFilePointer());
break;
}
// RowMutation must be at LEAST 10 bytes:
// 3 each for a non-empty Table and Key (including the 2-byte length from
// writeUTF/writeWithShortLength) and 4 bytes for column count.
// This prevents CRC by being fooled by special-case garbage in the file; see CASSANDRA-2128
if (serializedSize < 10)
break;
long claimedSizeChecksum = reader.readLong();
checksum.reset();
checksum.update(serializedSize);
if (checksum.getValue() != claimedSizeChecksum)
break; // entry wasn't synced correctly/fully. that's ok.
if (serializedSize > bytes.length)
bytes = new byte[(int) (1.2 * serializedSize)];
reader.readFully(bytes, 0, serializedSize);
claimedCRC32 = reader.readLong();
}
catch(EOFException eof)
{
break; // last CL entry didn't get completely written. that's ok.
}
checksum.update(bytes, 0, serializedSize);
if (claimedCRC32 != checksum.getValue())
{
// this entry must not have been fsynced. probably the rest is bad too,
// but just in case there is no harm in trying them (since we still read on an entry boundary)
continue;
}