Hi I am reading from logical replication stream continuously in infinite while loop. and I have another program that is continuously populating a table in the same database. I notice that after some time (around 5-10 minutes). I always get the exception
org.postgresql.util.PSQLException: Database connection failed when reading from copy
at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryExecutorImpl.java:1035)
at org.postgresql.core.v3.CopyDualImpl.readFromCopy(CopyDualImpl.java:41)
at org.postgresql.core.v3.replication.V3PGReplicationStream.receiveNextData(V3PGReplicationStream.java:155)
at org.postgresql.core.v3.replication.V3PGReplicationStream.readInternal(V3PGReplicationStream.java:124)
at org.postgresql.core.v3.replication.V3PGReplicationStream.read(V3PGReplicationStream.java:70)
at com.datamirror.ts.scrapers.postgresqlscraper.PGStreamReceiver.main(PGStreamReceiver.java:60)
Caused by: java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:220)
at java.net.SocketInputStream.read(SocketInputStream.java:152)
at org.postgresql.core.VisibleBufferedInputStream.readMore(VisibleBufferedInputStream.java:140)
at org.postgresql.core.VisibleBufferedInputStream.ensureBytes(VisibleBufferedInputStream.java:109)
at org.postgresql.core.VisibleBufferedInputStream.read(VisibleBufferedInputStream.java:67)
at org.postgresql.core.PGStream.receiveChar(PGStream.java:293)
at org.postgresql.core.v3.QueryExecutorImpl.processCopyResults(QueryExecutorImpl.java:1077)
at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryExecutorImpl.java:1033)
Here is my sample program :
import java.nio.ByteBuffer;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
import java.util.concurrent.TimeUnit;
import org.postgresql.PGConnection;
import org.postgresql.PGProperty;
import org.postgresql.replication.LogSequenceNumber;
import org.postgresql.replication.PGReplicationStream;
public class PGStreamReceiver {
public static void main(String[] args) {
try {
LogSequenceNumber startLsn = LogSequenceNumber.valueOf("0/2D8D0F0");
String url = "jdbc:postgresql://localhost:5432/postgres"
;
String user ="postgres";
String password = "xxxx";
Properties connectionProperties = new Properties();
PGProperty.USER.set(connectionProperties, user);
PGProperty.PASSWORD.set(connectionProperties, password);
PGProperty.ASSUME_MIN_SERVER_VERSION.set(connectionProperties, PostgreSQLConstants.MINIMUM_SUPPORTED_POSTGRESQL_VERSION);
PGProperty.REPLICATION.set(connectionProperties, PostgreSQLConstants.POSTGRESQL_REPLICATION_PROPERTY_VALUE);
PGProperty.PREFER_QUERY_MODE.set(connectionProperties, PostgreSQLConstants.POSTGRESQL_REPLICATION_PREFERRED_QUERY_MODE);
Connection postgresSQLConnection = DriverManager.getConnection(url, connectionProperties);
PGConnection postgrePGConnectionWrapper = postgresSQLConnection.unwrap(PGConnection.class);
PGReplicationStream stream = postgrePGConnectionWrapper.
getReplicationAPI()
.replicationStream()
.logical()
.withSlotName("pvn")
.withStartPosition(startLsn)
.withSlotOption(PostgreSQLConstants.INCLUDE_XID_IN_STREAM_CHANGES, true)
.withSlotOption(PostgreSQLConstants.INCLUDE_TIMESTAMP_IN_STREAM_CHANGES, true)
.withSlotOption(PostgreSQLConstants.EXCLUDE_EMPTY_TRANSACTION_IN_CHANGES, true)
//.withStatusInterval(PostgreSQLConstants.SERVER_FEEDBACK_TIME_INTERVAL_IN_SECONDS, TimeUnit.SECONDS)
.withStatusInterval(60, TimeUnit.SECONDS)
.start();
while(true)
{
ByteBuffer msg = stream.read();
if(msg == null)
{
return;
}
int offset = msg.arrayOffset();
byte[] source = msg.array();
int length = source.length - offset;
String logData = new String(source, offset, length);
System.out.print("1");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Any help is appreciated !! I am using postgres JDBC driver 42.2.2.