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

Class TransactionReconciliation

java.lang.Object

io.debezium.connector.oracle.logminer.processor.TransactionReconciliation

public class TransactionReconciliation
extends Object

Helper class that performs common transaction reconciliation. Transactions read from Oracle LogMiner are subject to containing events that need to be merged together to reflect a single logical SQL operation, such as events that pertain to LOB fields. This class facilities all the steps needed to merge events and reconcile a transaction.

Author:

Chris Cranford

Field Summary

Fields

Modifier and Type	Field	Description
private OracleConnectorConfig	connectorConfig
private static org.slf4j.Logger	LOGGER
private OracleDatabaseSchema	schema

Constructor Summary

Constructors

Constructor	Description
TransactionReconciliation(OracleConnectorConfig connectorConfig, OracleDatabaseSchema schema)

Method Summary

Modifier and Type	Method	Description
protected boolean	isForSameTableOrScn(LogMinerEvent event, LogMinerEvent prevEvent)	Checks whether the two events are for the same table or participate in the same system change.
protected boolean	isSameTableRow(DmlEvent event, DmlEvent prevEvent)	Checks whether the two events are for the same table row.
protected void	mergeNewColumns(DmlEvent event, DmlEvent prevEvent)	Merge column values from event with prevEvent.
protected List<String>	readAndCombineLobWriteEvents(Transaction transaction, int index, boolean binaryData)	Reads the transaction event queue and combines all LOB_WRITE events starting at the provided index.
protected int	readAndConsumeLobEraseEvents(Transaction transaction, int index)	Read and remove all LobErase events detected in the transaction event queue.
void	reconcile(Transaction transaction)	Reconcile the specified transaction by merging multiple events that should be emitted as a single logical event, such as changes made to LOB column types that involve multiple events.
protected boolean	shouldMergeDmlEvent(Transaction transaction, int index, DmlEvent event, DmlEvent prevEvent)	Attempts to merge the provided DML event with the previous event in the transaction.
protected boolean	shouldMergeSelectLobLocatorEvent(Transaction transaction, int index, SelectLobLocatorEvent event, DmlEvent prevEvent)	Attempts to merge the provided SEL_LOB_LOCATOR event with the previous event in the transaction.

Methods inherited from class java.lang.Object

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

Field Detail

LOGGER

private static final org.slf4j.Logger LOGGER

connectorConfig

private final OracleConnectorConfig connectorConfig

schema

private final OracleDatabaseSchema schema

Constructor Detail

TransactionReconciliation

public TransactionReconciliation(OracleConnectorConfig connectorConfig,
                                 OracleDatabaseSchema schema)

Method Detail

reconcile

public void reconcile(Transaction transaction)

Reconcile the specified transaction by merging multiple events that should be emitted as a single logical event, such as changes made to LOB column types that involve multiple events.

Parameters:

transaction - transaction to be reconciled, never null

shouldMergeSelectLobLocatorEvent

protected boolean shouldMergeSelectLobLocatorEvent(Transaction transaction,
                                                   int index,
                                                   SelectLobLocatorEvent event,
                                                   DmlEvent prevEvent)

Attempts to merge the provided SEL_LOB_LOCATOR event with the previous event in the transaction.

Parameters:

transaction - transaction being processed, never null

index - event index being processed

event - event being processed, never null

prevEvent - previous event in the transaction, can be null

Returns:

true if the event is merged, false if the event was not merged.

shouldMergeDmlEvent

protected boolean shouldMergeDmlEvent(Transaction transaction,
                                      int index,
                                      DmlEvent event,
                                      DmlEvent prevEvent)

Attempts to merge the provided DML event with the previous event in the transaction.

Parameters:

transaction - transaction being processed, never null

index - event index being processed

event - event being processed, never null

prevEvent - previous event in the transaction, can be null

Returns:

true if the event is merged, false if the event was not merged

readAndCombineLobWriteEvents

protected List<String> readAndCombineLobWriteEvents(Transaction transaction,
                                                    int index,
                                                    boolean binaryData)

Reads the transaction event queue and combines all LOB_WRITE events starting at the provided index. for a SEL_LOB_LOCATOR event which is for binary data (BLOB) data types.

Parameters:

transaction - transaction being processed, never null

index - index to the first LOB_WRITE operation

Returns:

list of string-based values for each LOB_WRITE operation

readAndConsumeLobEraseEvents

protected int readAndConsumeLobEraseEvents(Transaction transaction,
                                           int index)

Read and remove all LobErase events detected in the transaction event queue.

Parameters:

transaction - transaction being processed, never null

index - index to the first LOB_ERASE operation

Returns:

number of LOB_ERASE events consumed and removed from the event queue

isForSameTableOrScn

protected boolean isForSameTableOrScn(LogMinerEvent event,
                                      LogMinerEvent prevEvent)

Checks whether the two events are for the same table or participate in the same system change.

Parameters:

event - current event being processed, never null

prevEvent - previous/parent event that has been processed, may be null

Returns:

true if the two events are for the same table or system change number, false otherwise

isSameTableRow

protected boolean isSameTableRow(DmlEvent event,
                                 DmlEvent prevEvent)

Checks whether the two events are for the same table row.

Parameters:

event - current event being processed, never null

prevEvent - previous/parent event that has been processed, never null

Returns:

true if the two events are for the same table row, false otherwise

mergeNewColumns

protected void mergeNewColumns(DmlEvent event,
                               DmlEvent prevEvent)

Merge column values from event with prevEvent.

Parameters:

event - current event being processed, never null

prevEvent - previous/parent parent that has been processed, never null