com.sleepycat.je.log

Interface VersionedWriteLoggable

All Superinterfaces:

Loggable

All Known Implementing Classes:

BasicVersionedWriteLoggable, DatabaseId, DbOperationType, DupCountLN, FileSummaryLN, LN, MapLN, MasterTxn, Matchpoint, NameLN, PreparedTxn, ReadonlyTxn, ReplayTxn, ReplicatedDatabaseConfig, Trace, Txn, TxnAbort, TxnCommit, VersionedLN, VersionedWriteTxnEnd

public interface VersionedWriteLoggable
extends Loggable

A sub-interface of Loggable implemented by classes that can write themselves to a byte buffer in an earlier log format, for use by instances of ReplicableLogEntry that need to support an earlier log format during replication. See [#22336].

Classes that implement Loggable should implement this interface if they are included in replication data.

Implementing classes should document the version of the class's most recent format change. Log entry classes that contain VersionedWriteLoggable items can use that information to determine if they can copy the log contents for an entry directly or if they need to convert them in order to be compatible with a particular log version.

Method Summary

Modifier and Type	Method and Description
Collection<VersionedWriteLoggable>	getEmbeddedLoggables()
int	getLastFormatChange() Returns the log version of the most recent format change for this loggable item.
int	getLogSize(int logVersion, boolean forReplication) Returns the number of bytes needed to store this object in the format for the specified log version.
boolean	hasReplicationFormat() Returns whether this format has a variant that is optimized for replication.
boolean	isReplicationFormatWorthwhile(ByteBuffer logBuffer, int srcVersion, int destVersion) Returns whether it is worthwhile to materialize and then re-serialize a log entry in a format optimized for replication.
void	writeToLog(ByteBuffer logBuffer, int logVersion, boolean forReplication) Serializes this object into the specified buffer in the format for the specified log version.

Methods inherited from interface com.sleepycat.je.log.Loggable

dumpLog, getLogSize, getTransactionId, logicalEquals, readFromLog, writeToLog

Method Detail

getLastFormatChange

int getLastFormatChange()

Returns the log version of the most recent format change for this loggable item.

Returns:

the log version of the most recent format change

See Also:

ReplicableLogEntry.getLastFormatChange()

getEmbeddedLoggables

Collection<VersionedWriteLoggable> getEmbeddedLoggables()

See Also:

ReplicableLogEntry.getEmbeddedLoggables()

getLogSize

int getLogSize(int logVersion,
               boolean forReplication)

Returns the number of bytes needed to store this object in the format for the specified log version. Earlier log versions only need to be supported for log entries with format changes made in LogEntryType.LOG_VERSION_REPLICATE_OLDER or greater.

Parameters:

logVersion - the log version

forReplication - whether the entry will be sent over the wire, and not written to the log.

Returns:

the number of bytes to store this object for the log version

writeToLog

void writeToLog(ByteBuffer logBuffer,
                int logVersion,
                boolean forReplication)

Serializes this object into the specified buffer in the format for the specified log version. Earlier log versions only need to be supported for log entries with format changes made in LogEntryType.LOG_VERSION_REPLICATE_OLDER or greater.

Parameters:

logBuffer - the destination buffer

logVersion - the log version

forReplication - whether the entry will be sent over the wire, and not written to the log.

hasReplicationFormat

boolean hasReplicationFormat()

Returns whether this format has a variant that is optimized for replication.

isReplicationFormatWorthwhile

boolean isReplicationFormatWorthwhile(ByteBuffer logBuffer,
                                      int srcVersion,
                                      int destVersion)

Returns whether it is worthwhile to materialize and then re-serialize a log entry in a format optimized for replication. Implementations should attempt to check efficiently, without instantiating the log entry object. Some implementations will simply return false.

WARNING: The logBuffer position must not be changed by this method.

WARNING: The shared LogEntry object is used for calling this method, and this method must not change any of the fields in the object.

Parameters:

logBuffer - contains the entry that would be re-serialized.

srcVersion - the log version of entry in logBuffer.

destVersion - the version that would be used for re-serialization.