Package io.debezium.connector.mysql.legacy

Class ReconcilingBinlogReader

java.lang.Object

io.debezium.connector.mysql.legacy.ReconcilingBinlogReader

All Implemented Interfaces:

Reader

public class ReconcilingBinlogReader
extends Object
implements Reader

A reader that unifies the binlog positions of two binlog readers. To do this, at start time we evaluate the (now completed) states of the two binlog readers we want to unify, and create a new BinlogReader duplicating the lagging reader, but with a halting predicate that will halt it once it has passed the final position of the leading reader.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	ReconcilingBinlogReader.OffsetLimitPredicate	A Predicate that returns false for any record beyond a given offset.

Nested classes/interfaces inherited from interface io.debezium.connector.mysql.legacy.Reader

Reader.State

Field Summary

Fields

Modifier and Type	Field	Description
private Boolean	aReaderLeading
private final BinlogReader	binlogReaderA
private final BinlogReader	binlogReaderB
private final AtomicBoolean	completed
private static final org.slf4j.Logger	LOGGER
private final AtomicReference<MySqlPartition>	partition
private BinlogReader	reconcilingReader
private final AtomicBoolean	running
private final long	serverId
private final BinlogReader	unifiedReader
private final AtomicReference<Consumer<MySqlPartition>>	uponCompletion

Constructor Summary

Constructors

Constructor	Description
ReconcilingBinlogReader(BinlogReader binlogReaderA, BinlogReader binlogReaderB, BinlogReader unifiedReader, long serverId)	Create a reconciling Binlog Reader.

Method Summary

Modifier and Type	Method	Description
private void	checkLaggingLeadingInfo()
private void	completeSuccessfully()
private void	determineLeadingReader()
(package private) BinlogReader	getLaggingReader()
(package private) BinlogReader	getLeadingReader()
String	name()	Get the name of this reader.
List<org.apache.kafka.connect.source.SourceRecord>	poll()	Poll for the next batch of source records.
private void	setupUnifiedReader()
void	start(MySqlPartition partition)	Start the reader and return immediately.
Reader.State	state()	Get the current state of this reader.
void	stop()	Stop the reader from running and transition to the Reader.State.STOPPING state until all remaining records are consumed, at which point its state transitions to Reader.State.STOPPED.
void	uponCompletion(Consumer<MySqlPartition> handler)	Set the function that should be called when this reader transitions from the Reader.State.STOPPING to Reader.State.STOPPED state, which is after all generated records have been consumed via the poll method.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.debezium.connector.mysql.legacy.Reader

destroy, initialize

Field Details

LOGGER

private static final org.slf4j.Logger LOGGER

binlogReaderA

private final BinlogReader binlogReaderA

binlogReaderB

private final BinlogReader binlogReaderB

unifiedReader

private final BinlogReader unifiedReader

reconcilingReader

private BinlogReader reconcilingReader

aReaderLeading

private Boolean aReaderLeading

partition

private final AtomicReference<MySqlPartition> partition

running

private final AtomicBoolean running

completed

private final AtomicBoolean completed

uponCompletion

private final AtomicReference<Consumer<MySqlPartition>> uponCompletion

serverId

private final long serverId

Constructor Details

ReconcilingBinlogReader

public ReconcilingBinlogReader(BinlogReader binlogReaderA,
 BinlogReader binlogReaderB,
 BinlogReader unifiedReader,
 long serverId)

Create a reconciling Binlog Reader.

Parameters:

binlogReaderA - the first binlog reader to unify.

binlogReaderB - the second binlog reader to unify.

unifiedReader - the final, unified binlog reader that will run once the reconciliation is complete.

Method Details

name

public String name()

Description copied from interface: Reader

Get the name of this reader.

Specified by:

name in interface Reader

Returns:

the reader's name; never null

state

public Reader.State state()

Description copied from interface: Reader

Get the current state of this reader.

Specified by:

state in interface Reader

Returns:

the state; never null

uponCompletion

public void uponCompletion(Consumer<MySqlPartition> handler)

Description copied from interface: Reader

Set the function that should be called when this reader transitions from the Reader.State.STOPPING to Reader.State.STOPPED state, which is after all generated records have been consumed via the poll method.

This method should only be called while the reader is in the Reader.State.STOPPED state.

Specified by:

uponCompletion in interface Reader

Parameters:

handler - the function; may not be null

start

public void start(MySqlPartition partition)

Description copied from interface: Reader

Start the reader and return immediately. Once started, the SourceRecords generated by the reader can be obtained by periodically calling Reader.poll() until that method returns null.

This method does nothing if it is already running.

Specified by:

start in interface Reader

stop

public void stop()

Description copied from interface: Reader

Stop the reader from running and transition to the Reader.State.STOPPING state until all remaining records are consumed, at which point its state transitions to Reader.State.STOPPED.

Specified by:

stop in interface Reader

poll

public List<org.apache.kafka.connect.source.SourceRecord> poll()
                                                        throws InterruptedException

Description copied from interface: Reader

Poll for the next batch of source records. This method returns null only when all records generated by this reader have been processed, following the natural or explicit stopping of this reader. Note that this method may block if no additional records are available but the reader may produce more, thus callers should call this method continually until this method returns null.

Specified by:

poll in interface Reader

Returns:

the list of source records that may or may not be empty; or null when there will be no more records because the reader has completely Reader.State.STOPPED.

Throws:

InterruptedException - if this thread is interrupted while waiting for more records

completeSuccessfully

private void completeSuccessfully()

setupUnifiedReader

private void setupUnifiedReader()

determineLeadingReader

private void determineLeadingReader()

getLeadingReader

BinlogReader getLeadingReader()

getLaggingReader

BinlogReader getLaggingReader()

checkLaggingLeadingInfo

private void checkLaggingLeadingInfo()