org.rocksdb

Class Logger

java.lang.Object

org.rocksdb.AbstractNativeReference

org.rocksdb.AbstractImmutableNativeReference

org.rocksdb.RocksCallbackObject

org.rocksdb.Logger

All Implemented Interfaces:

java.lang.AutoCloseable

public abstract class Logger
extends RocksCallbackObject

This class provides a custom logger functionality in Java which wraps RocksDB logging facilities.

Using this class RocksDB can log with common Java logging APIs like Log4j or Slf4j without keeping database logs in the filesystem.

Performance

There are certain performance penalties using a Java Logger implementation within production code.

A log level can be set using Options or setInfoLogLevel(InfoLogLevel). The set log level influences the underlying native code. Each log message is checked against the set log level and if the log level is more verbose as the set log level, native allocations will be made and data structures are allocated.

Every log message which will be emitted by native code will trigger expensive native to Java transitions. So the preferred setting for production use is either InfoLogLevel.ERROR_LEVEL or InfoLogLevel.FATAL_LEVEL.

Field Summary

Fields inherited from class org.rocksdb.RocksCallbackObject

nativeHandle_

Constructor Summary

Constructors

Constructor and Description
Logger(DBOptions dboptions) AbstractLogger constructor.
Logger(Options options) AbstractLogger constructor.

Method Summary

Modifier and Type	Method and Description
protected long	createNewLoggerDbOptions(long dbOptions)
protected long	createNewLoggerOptions(long options)
protected void	disposeInternal() We override RocksCallbackObject.disposeInternal() as disposing of a rocksdb::LoggerJniCallback requires a slightly different approach as it is a std::shared_ptr
InfoLogLevel	infoLogLevel() Return the loggers log level.
protected byte	infoLogLevel(long handle)
protected long	initializeNative(long... nativeParameterHandles) Construct the Native C++ object which will callback to our object methods
protected abstract void	log(InfoLogLevel infoLogLevel, java.lang.String logMsg)
void	setInfoLogLevel(InfoLogLevel infoLogLevel) Set InfoLogLevel to AbstractLogger.
protected void	setInfoLogLevel(long handle, byte infoLogLevel)

Methods inherited from class org.rocksdb.AbstractImmutableNativeReference

close, disOwnNativeHandle, isOwningHandle

Methods inherited from class org.rocksdb.AbstractNativeReference

dispose, finalize

Methods inherited from class java.lang.Object

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

Constructor Detail

Logger

public Logger(Options options)

AbstractLogger constructor.

Important: the log level set within the Options instance will be used as maximum log level of RocksDB.

Parameters:

options - Options instance.

Logger

public Logger(DBOptions dboptions)

AbstractLogger constructor.

Important: the log level set within the DBOptions instance will be used as maximum log level of RocksDB.

Parameters:

dboptions - DBOptions instance.

Method Detail

initializeNative

protected long initializeNative(long... nativeParameterHandles)

Description copied from class: RocksCallbackObject

Construct the Native C++ object which will callback to our object methods

Specified by:

initializeNative in class RocksCallbackObject

Parameters:

nativeParameterHandles - An array of native handles for any parameter objects that are needed during construction

Returns:

The native handle of the C++ object which will callback to us

setInfoLogLevel

public void setInfoLogLevel(InfoLogLevel infoLogLevel)

Set InfoLogLevel to AbstractLogger.

Parameters:

infoLogLevel - InfoLogLevel instance.

infoLogLevel

public InfoLogLevel infoLogLevel()

Return the loggers log level.

Returns:

InfoLogLevel instance.

log

protected abstract void log(InfoLogLevel infoLogLevel,
                            java.lang.String logMsg)

createNewLoggerOptions

protected long createNewLoggerOptions(long options)

createNewLoggerDbOptions

protected long createNewLoggerDbOptions(long dbOptions)

setInfoLogLevel

protected void setInfoLogLevel(long handle,
                               byte infoLogLevel)

infoLogLevel

protected byte infoLogLevel(long handle)

disposeInternal

protected void disposeInternal()

We override RocksCallbackObject.disposeInternal() as disposing of a rocksdb::LoggerJniCallback requires a slightly different approach as it is a std::shared_ptr

Overrides:

disposeInternal in class RocksCallbackObject