Package io.debezium.connector.oracle.logminer.processor

Class TransactionCommitConsumer

java.lang.Object

io.debezium.connector.oracle.logminer.processor.TransactionCommitConsumer

All Implemented Interfaces:

BlockingConsumer<LogMinerEvent>, AutoCloseable

public class TransactionCommitConsumer
extends Object
implements AutoCloseable, BlockingConsumer<LogMinerEvent>

A consumer of transaction events at commit time that is capable of inspecting the event stream, merging events that should be merged when LOB support is enabled, and then delegating the final stream of events to a delegate consumer. When a table has a LOB or XML field, Oracle LogMiner often supplies us with synthetic events that deal with sub-tasks that occur in the database as a result of writing LOB data to the database. We would prefer to emit these synthetic events as a part of the overall logical event, whether that is an insert or update. An example of a scenario would be the following logical user action: INSERT INTO my_table (id,lob_field) values (1, 'some clob data'); Oracle LogMiner provides the connector with the following events: INSERT INTO my_table (id,lob_field) values (1, EMPTY_CLOB()); UPDATE my_table SET lob_field = 'some clob data' where id = 1; When LOB support is enabled, this consumer implementation will detect that the update is an event that should be merged with the previous insert event so that the emitted change events consists a single logical change, an insert that have an after section like:

     "after": {
         "id": 1,
         "lob_field": "some clob data"
     }
 

When LOB support isn't enabled, events are simply passed through to the delegate and no event inspection, merging, or buffering occurs.

Author:

Chris Cranford

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	TransactionCommitConsumer.AbstractUnderConstruction<T extends TransactionCommitConsumer.Fragment>
(package private) static class	TransactionCommitConsumer.ConstructionDetails
(package private) static class	TransactionCommitConsumer.Fragment
(package private) static interface	TransactionCommitConsumer.Handler<T>
(package private) static class	TransactionCommitConsumer.LobFragment
(package private) static class	TransactionCommitConsumer.LobUnderConstruction
private static class	TransactionCommitConsumer.RowState
(package private) static class	TransactionCommitConsumer.XmlFragment
(package private) static class	TransactionCommitConsumer.XmlUnderConstruction

Field Summary

Fields

Modifier and Type	Field	Description
private static final String	BLOB_TYPE
private static final String	CLOB_TYPE
private final OracleConnectorConfig	connectorConfig
private final TransactionCommitConsumer.ConstructionDetails	currentLobDetails
private final TransactionCommitConsumer.ConstructionDetails	currentXmlDetails
private final TransactionCommitConsumer.Handler<LogMinerEvent>	delegate
private static final org.slf4j.Logger	LOGGER
private static final String	NULL_COLUMN
private final Map<String,TransactionCommitConsumer.RowState>	rows
private final OracleDatabaseSchema	schema
private int	totalEvents
private int	transactionIndex

Constructor Summary

Constructors

Constructor	Description
TransactionCommitConsumer(TransactionCommitConsumer.Handler<LogMinerEvent> delegate, OracleConnectorConfig connectorConfig, OracleDatabaseSchema schema)

Method Summary

Modifier and Type	Method	Description
void	accept(LogMinerEvent event)
private void	acceptDmlEvent(DmlEvent event)
private void	acceptLobManipulationEvent(LogMinerEvent event)
private void	acceptManipulationEvent(LogMinerEvent event)
private void	acceptXmlManipulationEvent(LogMinerEvent event)
void	close()
private void	discardCurrentMergeState(TransactionCommitConsumer.ConstructionDetails details)
private void	dispatchChangeEvent(LogMinerEvent event)
private Object	getConstructable(TransactionCommitConsumer.ConstructionDetails details)
int	getTotalEvents()
private boolean	hasRowId(DmlEvent event)
private void	initConstructable(TransactionCommitConsumer.ConstructionDetails details, String rowId, String columnName, Table table, DmlEvent accumulatorEvent, Function<Object,Object> constructor)
private boolean	isLobColumn(Column column)
private boolean	isSelectLobLocatorForSameRow(DmlEvent into, DmlEvent event)
private boolean	isUpdateForSameTableWithLobColumnChanges(DmlEvent into, DmlEvent event)
private void	mergeEvents(DmlEvent into, DmlEvent from)
private Object[]	newValues(DmlEvent event)
private Object[]	oldValues(DmlEvent event)
private void	prepareAndDispatch(DmlEvent event)
private String	rowIdFromEvent(Table table, DmlEvent event)
private boolean	tryMerge(DmlEvent prev, DmlEvent next)

Methods inherited from class java.lang.Object

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

Field Details

LOGGER

private static final org.slf4j.Logger LOGGER

NULL_COLUMN

private static final String NULL_COLUMN

See Also:

• Constant Field Values

BLOB_TYPE

private static final String BLOB_TYPE

See Also:

• Constant Field Values

CLOB_TYPE

private static final String CLOB_TYPE

See Also:

• Constant Field Values

delegate

private final TransactionCommitConsumer.Handler<LogMinerEvent> delegate

connectorConfig

private final OracleConnectorConfig connectorConfig

schema

private final OracleDatabaseSchema schema

rows

private final Map<String,TransactionCommitConsumer.RowState> rows

currentLobDetails

private final TransactionCommitConsumer.ConstructionDetails currentLobDetails

currentXmlDetails

private final TransactionCommitConsumer.ConstructionDetails currentXmlDetails

transactionIndex

private int transactionIndex

totalEvents

private int totalEvents

Constructor Details

TransactionCommitConsumer

public TransactionCommitConsumer(TransactionCommitConsumer.Handler<LogMinerEvent> delegate,
 OracleConnectorConfig connectorConfig,
 OracleDatabaseSchema schema)

Method Details

close

public void close()
           throws InterruptedException

Specified by:

close in interface AutoCloseable

Throws:

InterruptedException

accept

public void accept(LogMinerEvent event)
            throws InterruptedException

Specified by:

accept in interface BlockingConsumer<LogMinerEvent>

Throws:

InterruptedException

getTotalEvents

public int getTotalEvents()

acceptDmlEvent

private void acceptDmlEvent(DmlEvent event)
                     throws InterruptedException

Throws:

InterruptedException

acceptManipulationEvent

private void acceptManipulationEvent(LogMinerEvent event)

acceptLobManipulationEvent

private void acceptLobManipulationEvent(LogMinerEvent event)

acceptXmlManipulationEvent

private void acceptXmlManipulationEvent(LogMinerEvent event)

getConstructable

private Object getConstructable(TransactionCommitConsumer.ConstructionDetails details)

initConstructable

private void initConstructable(TransactionCommitConsumer.ConstructionDetails details,
 String rowId,
 String columnName,
 Table table,
 DmlEvent accumulatorEvent,
 Function<Object,Object> constructor)

prepareAndDispatch

private void prepareAndDispatch(DmlEvent event)
                         throws InterruptedException

Throws:

InterruptedException

tryMerge

private boolean tryMerge(DmlEvent prev,
 DmlEvent next)

mergeEvents

private void mergeEvents(DmlEvent into,
 DmlEvent from)

isUpdateForSameTableWithLobColumnChanges

private boolean isUpdateForSameTableWithLobColumnChanges(DmlEvent into,
 DmlEvent event)

isSelectLobLocatorForSameRow

private boolean isSelectLobLocatorForSameRow(DmlEvent into,
 DmlEvent event)

isLobColumn

private boolean isLobColumn(Column column)

dispatchChangeEvent

private void dispatchChangeEvent(LogMinerEvent event)
                          throws InterruptedException

Throws:

InterruptedException

rowIdFromEvent

private String rowIdFromEvent(Table table,
 DmlEvent event)

newValues

private Object[] newValues(DmlEvent event)

oldValues

private Object[] oldValues(DmlEvent event)

discardCurrentMergeState

private void discardCurrentMergeState(TransactionCommitConsumer.ConstructionDetails details)

hasRowId

private boolean hasRowId(DmlEvent event)