Package io.debezium.connector.postgresql.connection

Class WalPositionLocator

java.lang.Object
io.debezium.connector.postgresql.connection.WalPositionLocator
public class WalPositionLocator extends Object
This class is responsible for finding out a LSN from which Debezium should resume streaming after connector restarts. The LSNs are not guaranteed to be ordered in the WAL. LSN of commits are ordered and LSNs inside a transaction are ordered. It is thus necessary to find out the beginning of the unprocessed transaction and the LSN from which the streaming should start.
Author:
Jiri Pechanec

  • Field Details

    • LOGGER

      private static final org.slf4j.Logger LOGGER

    • lastCommitStoredLsn

      private final Lsn lastCommitStoredLsn

    • lastEventStoredLsn

      private final Lsn lastEventStoredLsn

    • lastProcessedMessageType

      private final ReplicationMessage.Operation lastProcessedMessageType

    • txStartLsn

      private Lsn txStartLsn

    • lsnAfterLastEventStoredLsn

      private Lsn lsnAfterLastEventStoredLsn

    • firstLsnReceived

      private Lsn firstLsnReceived

    • passMessages

      private boolean passMessages

    • startStreamingLsn

      private Lsn startStreamingLsn

    • storeLsnAfterLastEventStoredLsn

      private boolean storeLsnAfterLastEventStoredLsn

    • lsnSeen

      private Set<Lsn> lsnSeen

  • Constructor Details

    • WalPositionLocator

      public WalPositionLocator(Lsn lastCommitStoredLsn, Lsn lastEventStoredLsn, ReplicationMessage.Operation lastProcessedMessageType)

    • WalPositionLocator

      public WalPositionLocator()

  • Method Details

    • resumeFromLsn

      public Optional<Lsn> resumeFromLsn(Lsn currentLsn, ReplicationMessage message)
      Returns:
      the first LSN from which processing should be started or empty if the position has not been found yet

    • skipMessage

      public boolean skipMessage(Lsn lsn)
      Decides whether the message with given LSN should be removed or not based on previously located LSN point.
      Parameters:
      lsn -
      Returns:
      true if the message should be skipped, false otherwise

    • enableFiltering

      public void enableFiltering()
      Enables filtering of message LSNs based on calculated position.

    • searchingEnabled

      public boolean searchingEnabled()
      Returns:
      true if searching of WAL position should be executed

    • getLastEventStoredLsn

      public Lsn getLastEventStoredLsn()

    • getLastCommitStoredLsn

      public Lsn getLastCommitStoredLsn()

    • toString

      public String toString()
      Overrides:
      toString in class Object