Package io.debezium.connector.mysql.strategy

Class AbstractHistoryRecordComparator

java.lang.Object

io.debezium.relational.history.HistoryRecordComparator

io.debezium.connector.mysql.strategy.AbstractHistoryRecordComparator

Direct Known Subclasses:

MariaDbHistoryRecordComparator, MySqlHistoryRecordComparator

public abstract class AbstractHistoryRecordComparator
extends HistoryRecordComparator

Author:

Chris Cranford

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	AbstractHistoryRecordComparator.BinlogFilename

Field Summary

Fields

Modifier and Type	Field	Description
private final Predicate<String>	gtidSourceFilter

Fields inherited from class io.debezium.relational.history.HistoryRecordComparator

INSTANCE

Constructor Summary

Constructors

Constructor	Description
AbstractHistoryRecordComparator(Predicate<String> gtidSourceFilter)

Method Summary

Modifier and Type	Method	Description
protected abstract GtidSet	createGtidSet(String gtidSet)
boolean	isPositionAtOrBefore(Document recorded, Document desired)	Determine whether the first offset is at or before the point in time of the second offset, where the offsets are given in JSON representation of the maps returned by MySqlOffsetContext.getOffset().

Methods inherited from class io.debezium.relational.history.HistoryRecordComparator

isAtOrBefore, isSameSource

Methods inherited from class java.lang.Object

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

Field Details

gtidSourceFilter

private final Predicate<String> gtidSourceFilter

Constructor Details

AbstractHistoryRecordComparator

public AbstractHistoryRecordComparator(Predicate<String> gtidSourceFilter)

Method Details

createGtidSet

protected abstract GtidSet createGtidSet(String gtidSet)

isPositionAtOrBefore

@VisibleForTesting
public boolean isPositionAtOrBefore(Document recorded,
 Document desired)

Determine whether the first offset is at or before the point in time of the second offset, where the offsets are given in JSON representation of the maps returned by MySqlOffsetContext.getOffset().

This logic makes a significant assumption: once a MySQL server/cluster has GTIDs enabled, they will never be disabled. This is the only way to compare a position with a GTID to a position without a GTID, and we conclude that any position with a GTID is *after* the position without.

When both positions have GTIDs, then we compare the positions by using only the GTIDs. Of course, if the GTIDs are the same, then we also look at whether they have snapshots enabled.

Overrides:

isPositionAtOrBefore in class HistoryRecordComparator

Parameters:

recorded - the position obtained from recorded history; never null

desired - the desired position that we want to obtain, which should be after some recorded positions, at some recorded positions, and before other recorded positions; never null

Returns:

true if the recorded position is at or before the desired position; or false otherwise