io.debezium.connector.postgresql.connection

Interface ReplicationStream

All Superinterfaces:

AutoCloseable

public interface ReplicationStream
extends AutoCloseable

A stream from which messages sent by a logical decoding plugin can be consumed over a replication connection.

Author:

Horia Chiorean (hchiorea@redhat.com)

Method Summary

Modifier and Type	Method and Description
void	close() //TODO author=Horia Chiorean date=13/10/2016 description=Don't use this for now, because of the bug from the PG server This is stream is closed atm.
void	flushLSN() Sends a message to the server informing it about that latest position in the WAL that this stream has read via ReplicationConnection.startStreaming() or ReplicationConnection.startStreaming(Long).
Long	lastReceivedLSN() Returns the value for the latest server received LSN during a read operation.
PgProto.RowMessage	read() Blocks and waits for a Protobuf message to be sent over a replication connection.
PgProto.RowMessage	readPending() Attempts to read a Protobuf message from a replication connection, returning that message if it's available or returning null if nothing is available.

Method Detail

read

PgProto.RowMessage read()
                 throws SQLException

Blocks and waits for a Protobuf message to be sent over a replication connection. Once a message has been received, the value of the last received LSN will also be updated accordingly.

Returns:

a PgProto.RowMessage instance; this may return null if the server sends back a message which has already been reported as consumed via the flushLSN() method.

Throws:

SQLException - if anything unexpected fails

See Also:

PGReplicationStream.read()

readPending

PgProto.RowMessage readPending()
                        throws SQLException

Attempts to read a Protobuf message from a replication connection, returning that message if it's available or returning null if nothing is available. Once a message has been received, the value of the last received LSN will also be updated accordingly.

Returns:

a PgProto.RowMessage instance if a message is available and was written by a server or null if nothing is available from the server or the server sends a message that has already been reported as consumed via the flushLSN() method.

Throws:

SQLException - if anything unexpected fails

See Also:

PGReplicationStream.readPending()

flushLSN

void flushLSN()
       throws SQLException

Sends a message to the server informing it about that latest position in the WAL that this stream has read via ReplicationConnection.startStreaming() or ReplicationConnection.startStreaming(Long).

This essentially tells the server that this stream has successfully processed messages up to the current read cursor and so the server is free to discard older segments with earlier LSNs. It also affects the catch-up behavior once a slot is restarted and the server attempt to bring it up-to-date.

Throws:

SQLException - if anything goes wrong

lastReceivedLSN

Long lastReceivedLSN()

Returns the value for the latest server received LSN during a read operation. The value is always updated once messages are read via the ReplicationConnection.startStreaming() or ReplicationConnection.startStreaming(Long) methods.

Returns:

a Long value, possibly null if this is called before anything has been read

close

void close()
    throws Exception

//TODO author=Horia Chiorean date=13/10/2016 description=Don't use this for now, because of the bug from the PG server This is stream is closed atm. once the replication connection which created it is closed.

Specified by:

close in interface AutoCloseable

Throws:

Exception

See Also:

PGReplicationStream.close()