org.apache.cassandra.utils.binlog

Class BinLog

java.lang.Object

org.apache.cassandra.utils.binlog.BinLog

All Implemented Interfaces:

java.lang.Runnable

public class BinLog
extends java.lang.Object
implements java.lang.Runnable

Bin log is a is quick and dirty binary log that is kind of a NIH version of binary logging with a traditional logging framework. It's goal is good enough performance, predictable footprint, simplicity in terms of implementation and configuration and most importantly minimal impact on producers of log records. Performance safety is accomplished by feeding items to the binary log using a weighted queue and dropping records if the binary log falls sufficiently far behind. Simplicity and good enough perforamance is achieved by using a single log writing thread as well as Chronicle Queue to handle writing the log, making it available for readers, as well as log rolling.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BinLog.ReleaseableWriteMarshallable

Constructor Summary

Constructors

Constructor and Description
BinLog(java.nio.file.Path path, net.openhft.chronicle.queue.RollCycle rollCycle, int maxQueueWeight, BinLogArchiver archiver)

Method Summary

Modifier and Type	Method and Description
void	finalize() There is a race where we might not release a buffer, going to let finalization catch it since it shouldn't happen to a lot of buffers.
boolean	offer(BinLog.ReleaseableWriteMarshallable record) Offer a record to the log.
void	put(BinLog.ReleaseableWriteMarshallable record) Put a record into the log.
void	run()
void	start() Start the consumer thread that writes log records.
void	stop() Stop the consumer thread that writes log records.

Methods inherited from class java.lang.Object

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

Constructor Detail

BinLog

public BinLog(java.nio.file.Path path,
              net.openhft.chronicle.queue.RollCycle rollCycle,
              int maxQueueWeight,
              BinLogArchiver archiver)

Parameters:

path - Path to store the BinLog. Can't be shared with anything else.

rollCycle - How often to roll the log file so it can potentially be deleted

maxQueueWeight - Maximum weight of in memory queue for records waiting to be written to the file before blocking or dropping

Method Detail

start

public void start()

Start the consumer thread that writes log records. Can only be done once.

stop

public void stop()
          throws java.lang.InterruptedException

Stop the consumer thread that writes log records. Can be called multiple times.

Throws:

java.lang.InterruptedException

offer

public boolean offer(BinLog.ReleaseableWriteMarshallable record)

Offer a record to the log. If the in memory queue is full the record will be dropped and offer will return false.

Parameters:

record - The record to write to the log

Returns:

true if the record was queued and false otherwise

put

public void put(BinLog.ReleaseableWriteMarshallable record)
         throws java.lang.InterruptedException

Put a record into the log. If the in memory queue is full the putting thread will be blocked until there is space or it is interrupted.

Parameters:

record - The record to write to the log

Throws:

java.lang.InterruptedException

run

public void run()

Specified by:

run in interface java.lang.Runnable

finalize

public void finalize()

There is a race where we might not release a buffer, going to let finalization catch it since it shouldn't happen to a lot of buffers. Only test code would run into it anyways.

Overrides:

finalize in class java.lang.Object