PostgreSQL JDBC Driver 42.7.2 · org.postgresql.replication.PGReplicationStream

Method Summary

Modifier and Type	Method and Description
public void	close() Redeclares java.lang.AutoCloseable.close. Stop replication changes from server and free resources.
public void	forceUpdateStatus() Force send last received, flushed and applied LSN status to backend.
public LogSequenceNumber	Returns: not null location of the last WAL applied in the standby. getLastAppliedLSN() Last applied lsn sent in update message to backed.
public LogSequenceNumber	Returns: NOT NULL location of the last WAL flushed to disk in the standby. getLastFlushedLSN() Last flushed LSN sent in update message to backend.
public LogSequenceNumber	Returns: NOT NULL LSN position that was receive last time via `PGReplicationStream#read()` method getLastReceiveLSN() Parameter updates by execute `PGReplicationStream#read()` method.
public boolean	Returns: `true` if replication stream was already close, otherwise return `false` isClosed()
public @Nullable ByteBuffer	Returns: not null byte array received by replication protocol, return ByteBuffer wrap around received byte array with use offset, so, use `ByteBuffer#array()` carefully read() Read next wal record from backend.
public @Nullable ByteBuffer	Returns: byte array received by replication protocol or NULL if pending message from server absent. Returns ByteBuffer wrap around received byte array with use offset, so, use `ByteBuffer#array()` carefully. readPending() Read next WAL record from backend.
public void	setAppliedLSN(LogSequenceNumber NOT NULL location of the last WAL applied in the standby. applied) Inform backend which LSN has been applied on standby.
public void	setFlushedLSN(LogSequenceNumber NOT NULL location of the last WAL flushed to disk in the standby. flushed) Set flushed LSN.

Method Detail

close	back to summary
public void close() throws SQLException Redeclares java.lang.AutoCloseable.close. Stop replication changes from server and free resources. After that connection can be reuse to another queries. Also after close current stream they cannot be used anymore. Note This method can spend much time for logical replication stream on postgresql version 9.6 and lower, because postgresql have bug - during decode big transaction to logical form and during wait new changes postgresql ignore messages from client. As workaround you can close replication connection instead of close replication stream. For more information about it problem see mailing list thread Stopping logical replication protocol Annotations @Override Exceptions SQLException: when some internal exception occurs during end streaming

back to summary

public void close() throws SQLException

Redeclares java.lang.AutoCloseable.close.

Stop replication changes from server and free resources. After that connection can be reuse to another queries. Also after close current stream they cannot be used anymore.

Note

This method can spend much time for logical replication stream on postgresql version 9.6 and lower, because postgresql have bug - during decode big transaction to logical form and during wait new changes postgresql ignore messages from client. As workaround you can close replication connection instead of close replication stream. For more information about it problem see mailing list thread Stopping logical replication protocol

Annotations

@Override

Exceptions

SQLException:: when some internal exception occurs during end streaming

forceUpdateStatus back to summary

forceUpdateStatus	back to summary
public void forceUpdateStatus() throws SQLException Force send last received, flushed and applied LSN status to backend. You cannot send LSN status explicitly because `PGReplicationStream` sends the status to backend periodically by configured interval via `LogicalReplicationOptions#getStatusInterval` Exceptions SQLException: when some internal exception occurs during read from stream See Also `LogicalReplicationOptions#getStatusInterval()`

public void forceUpdateStatus() throws SQLException

Force send last received, flushed and applied LSN status to backend. You cannot send LSN status explicitly because PGReplicationStream sends the status to backend periodically by configured interval via LogicalReplicationOptions#getStatusInterval

Exceptions

SQLException:: when some internal exception occurs during read from stream

getLastAppliedLSN back to summary

getLastAppliedLSN	back to summary
public LogSequenceNumber getLastAppliedLSN() Last applied lsn sent in update message to backed. Parameter updates only via `PGReplicationStream#setAppliedLSN(LogSequenceNumber)` It is safe to call this method in a thread different than the main thread. Returns:LogSequenceNumber not null location of the last WAL applied in the standby.

public LogSequenceNumber getLastAppliedLSN()

Last applied lsn sent in update message to backed. Parameter updates only via PGReplicationStream#setAppliedLSN(LogSequenceNumber)

It is safe to call this method in a thread different than the main thread.

Returns:LogSequenceNumber: not null location of the last WAL applied in the standby.

getLastFlushedLSN back to summary

getLastFlushedLSN	back to summary
public LogSequenceNumber getLastFlushedLSN() Last flushed LSN sent in update message to backend. Parameter updates only via `PGReplicationStream#setFlushedLSN(LogSequenceNumber)` It is safe to call this method in a thread different than the main thread. Returns:LogSequenceNumber NOT NULL location of the last WAL flushed to disk in the standby.

public LogSequenceNumber getLastFlushedLSN()

Last flushed LSN sent in update message to backend. Parameter updates only via PGReplicationStream#setFlushedLSN(LogSequenceNumber)

It is safe to call this method in a thread different than the main thread.

Returns:LogSequenceNumber: NOT NULL location of the last WAL flushed to disk in the standby.

getLastReceiveLSN back to summary

getLastReceiveLSN	back to summary
public LogSequenceNumber getLastReceiveLSN() Parameter updates by execute `PGReplicationStream#read()` method. It is safe to call this method in a thread different than the main thread. However, usually this method is called in the main thread after a successful `PGReplicationStream#read()` or `PGReplicationStream#readPending()`, to get the LSN corresponding to the received record. Returns:LogSequenceNumber NOT NULL LSN position that was receive last time via `PGReplicationStream#read()` method

public LogSequenceNumber getLastReceiveLSN()

Parameter updates by execute PGReplicationStream#read() method.

It is safe to call this method in a thread different than the main thread. However, usually this method is called in the main thread after a successful PGReplicationStream#read() or PGReplicationStream#readPending(), to get the LSN corresponding to the received record.

Returns:LogSequenceNumber: NOT NULL LSN position that was receive last time via PGReplicationStream#read() method

isClosed	back to summary
public boolean isClosed() Returns:boolean `true` if replication stream was already close, otherwise return `false`

read back to summary

read	back to summary
public @Nullable ByteBuffer read() throws SQLException Read next wal record from backend. It method can be block until new message will not get from server. A single WAL record is never split across two XLogData messages. When a WAL record crosses a WAL page boundary, and is therefore already split using continuation records, it can be split at the page boundary. In other words, the first main WAL record and its continuation records can be sent in different XLogData messages. Returns:@Nullable ByteBuffer not null byte array received by replication protocol, return ByteBuffer wrap around received byte array with use offset, so, use `ByteBuffer#array()` carefully Exceptions SQLException: when some internal exception occurs during read from stream

public @Nullable ByteBuffer read() throws SQLException

Read next wal record from backend. It method can be block until new message will not get from server.

A single WAL record is never split across two XLogData messages. When a WAL record crosses a WAL page boundary, and is therefore already split using continuation records, it can be split at the page boundary. In other words, the first main WAL record and its continuation records can be sent in different XLogData messages.

Returns:@Nullable ByteBuffer

not null byte array received by replication protocol, return ByteBuffer wrap around received byte array with use offset, so, use ByteBuffer#array() carefully

Exceptions

SQLException:: when some internal exception occurs during read from stream

readPending back to summary

readPending	back to summary
public @Nullable ByteBuffer readPending() throws SQLException Read next WAL record from backend. This method does not block and in contrast to `PGReplicationStream#read()`. If message from backend absent return null. It allow periodically check message in stream and if they absent sleep some time, but it time should be less than `CommonOptions#getStatusInterval()` to avoid disconnect from the server. A single WAL record is never split across two XLogData messages. When a WAL record crosses a WAL page boundary, and is therefore already split using continuation records, it can be split at the page boundary. In other words, the first main WAL record and its continuation records can be sent in different XLogData messages. Returns:@Nullable ByteBuffer byte array received by replication protocol or NULL if pending message from server absent. Returns ByteBuffer wrap around received byte array with use offset, so, use `ByteBuffer#array()` carefully. Exceptions SQLException: when some internal exception occurs during read from stream

public @Nullable ByteBuffer readPending() throws SQLException

Read next WAL record from backend. This method does not block and in contrast to PGReplicationStream#read(). If message from backend absent return null. It allow periodically check message in stream and if they absent sleep some time, but it time should be less than CommonOptions#getStatusInterval() to avoid disconnect from the server.

Returns:@Nullable ByteBuffer

byte array received by replication protocol or NULL if pending message from server absent. Returns ByteBuffer wrap around received byte array with use offset, so, use ByteBuffer#array() carefully.

Exceptions

SQLException:: when some internal exception occurs during read from stream

setAppliedLSN back to summary

setAppliedLSN	back to summary
public void setAppliedLSN(LogSequenceNumber applied) Inform backend which LSN has been applied on standby. Feedback will send to backend on next update status iteration. It is safe to call this method in a thread different than the main thread. The updated value will be sent to the backend in the next status update run. Parameters applied:LogSequenceNumber NOT NULL location of the last WAL applied in the standby. See Also `PGReplicationStream#forceUpdateStatus()`

public void setAppliedLSN(LogSequenceNumber applied)

Inform backend which LSN has been applied on standby. Feedback will send to backend on next update status iteration.

It is safe to call this method in a thread different than the main thread. The updated value will be sent to the backend in the next status update run.

Parameters

applied:LogSequenceNumber: NOT NULL location of the last WAL applied in the standby.

setFlushedLSN back to summary

setFlushedLSN	back to summary
public void setFlushedLSN(LogSequenceNumber flushed) Set flushed LSN. This parameter will be sent to backend on next update status iteration. Flushed LSN position help backend define which WAL can be recycled. It is safe to call this method in a thread different than the main thread. The updated value will be sent to the backend in the next status update run. Parameters flushed:LogSequenceNumber NOT NULL location of the last WAL flushed to disk in the standby. See Also `PGReplicationStream#forceUpdateStatus()`

public void setFlushedLSN(LogSequenceNumber flushed)

Set flushed LSN. This parameter will be sent to backend on next update status iteration. Flushed LSN position help backend define which WAL can be recycled.

It is safe to call this method in a thread different than the main thread. The updated value will be sent to the backend in the next status update run.

Parameters

flushed:LogSequenceNumber: NOT NULL location of the last WAL flushed to disk in the standby.

public Interface PGReplicationStream

Method Summary

Method Detail