org.postgresql.util.PSQLException: Connection refused
36,459
Solution 1
Error "Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections." suggests:
Postgres is not started, to check this run
netstat -aand check if Postgres is waiting for connections on 5432 portwrong username/password - try to connect to Postgres using console or PG Admin using these credentials
it may happen, especially if Postgres is on Linux box, that is does not allow TCP/IP connections because of the security reasons. You need to enable that. Search the net for "enable remote Postgres connection" or "enable Postgres tcp/ip connection", there is planty of information.
Solution 2
You need to configure postgresql.conf and pg_hba.conf file in your postgres directory.
Open postgresql.conf file and replace line
listen_addresses = 'localhost'
with
listen_addresses = '*'
if there is a '#' start of listen_addresses just delete it, it makes them comment line. now restart postgresql server.
pg_hba.conf
host all all 0.0.0.0/0 md5
add this line at the end of the pg_hba.conf.
md5 means password is neccesary for connection if you dont want any password you can change it to trust this accepts connection unconditionally.
0.0.0.0/0 means every ip address, you can also change it as you want.
Author by
user2328488
Updated on April 28, 2021Comments
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user2328488 over 1 year
I wanted to test execution of function of an indexing from other host because this function not absolutely correctly fulfilled in hadoop to the program. But I had problems with connection to a database from other host as it is explained below. I don't understand in what a problem.
I wrote following the java program
import java.io.*; import java.util.*; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.logging.Level; import java.util.*; public class Sample { public static void main (String[] args) throws IOException { int CountComputers; FileInputStream fstream = new FileInputStream( "/export/hadoop-1.0.1/bin/countcomputers.txt"); BufferedReader br = new BufferedReader(new InputStreamReader(fstream)); String result=br.readLine(); CountComputers=Integer.parseInt(result); input.close(); fstream.close(); Connection con = null; Statement st = null; ResultSet rs = null; String url = "jdbc:postgresql://192.168.1.8:5432/NexentaSearch"; String user = "postgres"; String password = "valter89"; //Class.forName("org.postgresql.Driver"); ArrayList<String> paths = new ArrayList<String>(); try { Class.forName("org.postgresql.Driver"); con = DriverManager.getConnection(url, user, password); st = con.createStatement(); rs = st.executeQuery("select path from tasks order by id"); while (rs.next()) { paths.add(rs.getString(1)); }; PrintWriter zzz = null; try { zzz = new PrintWriter(new FileOutputStream("/export/hadoop-1.0.1/bin/readwaysfromdatabase.txt")); } catch(FileNotFoundException e) { System.out.println("Error"); System.exit(0); } for (int i=0; i<paths.size(); i++) { zzz.println("paths[i]=" + paths.get(i) + "\n"); } zzz.close(); } catch (SQLException e) { System.out.println("Connection Failed! Check output console"); e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } }I launched Sample.jar by means of a command
./java -jar -Djava.library.path=/opt/jdk1.7.0_06/lib /Samplejavaprogram/Sample.jarand as a result I received the following messages
Connection Failed! Check output console org.postgresql.util.PSQLException: Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections. at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:136) at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:66) at org.postgresql.jdbc2.AbstractJdbc2Connection.<init>(AbstractJdbc2Connection.java:125) at org.postgresql.jdbc3.AbstractJdbc3Connection.<init>(AbstractJdbc3Connection.java:30) at org.postgresql.jdbc3.Jdbc3Connection.<init>(Jdbc3Connection.java:24) at org.postgresql.Driver.makeConnection(Driver.java:393) at org.postgresql.Driver.connect(Driver.java:267) at java.sql.DriverManager.getConnection(DriverManager.java:579) at java.sql.DriverManager.getConnection(DriverManager.java:221) at Sample.main(Sample.java:33) Caused by: java.net.ConnectException: Connection timed out at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at java.net.Socket.<init>(Socket.java:425) at java.net.Socket.<init>(Socket.java:208) at org.postgresql.core.PGStream.<init>(PGStream.java:62) at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:76) ... 9 moreI launched the file from a host with the address 192.168.1.10. Help to eliminate an error. In what cause of error? What it is necessary to make?
netstat -a UDP: IPv4 Local Address Remote Address State -------------------- -------------------- ---------- *.bootpc Idle *.dhcpv6-client Idle *.* Unbound *.* Unbound *.sunrpc Idle *.* Unbound *.38606 Idle *.sunrpc Idle *.* Unbound *.40712 Idle *.* Unbound *.* Unbound *.* Unbound *.54122 Idle *.41742 Idle *.* Unbound *.lockd Idle *.lockd Idle *.59670 Idle *.42840 Idle *.43065 Idle *.39546 Idle *.34243 Idle *.35383 Idle *.40746 Idle *.40832 Idle 192.168.1.2.bootpc Idle *.mdns Idle *.mdns Idle 192.168.1.2.ntp Idle *.snmpd Idle *.ntp Idle *.ntp Idle localhost.localdomain.ntp Idle myhost2.ntp Idle UDP: IPv6 Local Address Remote Address State If --------------------------------- --------------------------------- ---------- ----- *.dhcpv6-client Idle *.* Unbound localhost.44111 localhost.44111 Connected *.sunrpc Idle *.* Unbound *.38606 Idle *.54122 Idle *.* Unbound *.lockd Idle *.42840 Idle *.39546 Idle *.35383 Idle *.40832 Idle *.ntp Idle localhost.ntp Idle TCP: IPv4 Local Address Remote Address Swind Send-Q Rwind Recv-Q State -------------------- -------------------- ----- ------ ----- ------ ----------- localhost.localdomain.4999 *.* 0 0 128000 0 LISTEN *.2001 *.* 0 0 128000 0 LISTEN *.2002 *.* 0 0 128000 0 LISTEN *.2003 *.* 0 0 128000 0 LISTEN *.16049 *.* 0 0 128000 0 LISTEN *.5432 *.* 0 0 128000 0 LISTEN *.sunrpc *.* 0 0 128000 0 LISTEN *.* *.* 0 0 128000 0 IDLE *.sunrpc *.* 0 0 128000 0 LISTEN *.* *.* 0 0 128000 0 IDLE *.54002 *.* 0 0 128000 0 LISTEN *.49023 *.* 0 0 128000 0 LISTEN *.55493 *.* 0 0 1049200 0 LISTEN *.46659 *.* 0 0 1048952 0 LISTEN *.lockd *.* 0 0 1049200 0 LISTEN *.lockd *.* 0 0 1048952 0 LISTEN *.45361 *.* 0 0 128000 0 LISTEN localhost.localdomain.36084 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED *.53943 *.* 0 0 128000 0 LISTEN localhost.localdomain.2001 localhost.localdomain.36084 139060 0 130880 0 ESTABLISHED localhost.localdomain.44644 localhost.localdomain.2012 34765 0 139264 0 ESTABLISHED localhost.localdomain.2012 localhost.localdomain.44644 139060 0 139060 0 ESTABLISHED *.36068 *.* 0 0 128000 0 LISTEN *.57055 *.* 0 0 128000 0 LISTEN *.login *.* 0 0 128000 0 LISTEN *.finger *.* 0 0 128000 0 LISTEN *.telnet *.* 0 0 128000 0 LISTEN *.shell *.* 0 0 128000 0 LISTEN *.40524 *.* 0 0 128000 0 LISTEN *.60838 *.* 0 0 128000 0 LISTEN *.47648 *.* 0 0 128000 0 LISTEN *.56894 *.* 0 0 128000 0 LISTEN *.48461 *.* 0 0 128000 0 LISTEN *.53672 *.* 0 0 128000 0 LISTEN *.42108 *.* 0 0 128000 0 LISTEN *.63720 *.* 0 0 128000 0 LISTEN *.ssh *.* 0 0 128000 0 LISTEN localhost.localdomain.smtp *.* 0 0 128000 0 LISTEN localhost.localdomain.submission *.* 0 0 128000 0 LISTEN *.80 *.* 0 0 128000 0 LISTEN *.* *.* 0 0 128000 0 IDLE *.2000 *.* 0 0 128000 0 LISTEN *.* *.* 0 0 128000 0 IDLE *.443 *.* 0 0 128000 0 LISTEN *.* *.* 0 0 128000 0 IDLE localhost.localdomain.38137 localhost.localdomain.2003 65440 0 139264 0 ESTABLISHED localhost.localdomain.2003 localhost.localdomain.38137 139060 0 130880 0 ESTABLISHED localhost.localdomain.63918 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED localhost.localdomain.2001 localhost.localdomain.63918 139060 0 130880 0 ESTABLISHED myhost2.ssh 192.168.1.4.7431 65548 0 128480 0 ESTABLISHED localhost.localdomain.34057 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED localhost.localdomain.2001 localhost.localdomain.34057 139060 0 130880 0 ESTABLISHED localhost.localdomain.37015 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED localhost.localdomain.2001 localhost.localdomain.37015 139060 0 130880 0 ESTABLISHED *.2011 *.* 0 0 131072 0 LISTEN localhost.localdomain.36598 localhost.localdomain.2002 65440 0 139264 0 ESTABLISHED localhost.localdomain.2002 localhost.localdomain.36598 139060 0 130880 0 ESTABLISHED localhost.localdomain.4000 *.* 0 0 131072 0 LISTEN localhost.localdomain.53161 localhost.localdomain.2011 34765 0 139264 0 ESTABLISHED localhost.localdomain.2011 localhost.localdomain.53161 139060 0 139060 0 ESTABLISHED localhost.localdomain.43878 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED localhost.localdomain.2001 localhost.localdomain.43878 139060 0 130880 0 ESTABLISHED localhost.localdomain.50976 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED localhost.localdomain.2001 localhost.localdomain.50976 139060 0 130880 0 ESTABLISHED localhost.localdomain.62633 localhost.localdomain.2012 34765 0 139264 0 ESTABLISHED localhost.localdomain.2012 localhost.localdomain.62633 139060 0 139060 0 ESTABLISHED *.2012 *.* 0 0 131072 0 LISTEN localhost.localdomain.34418 localhost.localdomain.2012 34765 0 139264 0 ESTABLISHED localhost.localdomain.2012 localhost.localdomain.34418 139060 0 139060 0 ESTABLISHED localhost.localdomain.34356 localhost.localdomain.2011 34765 0 139264 0 ESTABLISHED localhost.localdomain.2011 localhost.localdomain.34356 139060 0 139060 0 ESTABLISHED localhost.localdomain.62884 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED localhost.localdomain.2001 localhost.localdomain.62884 139060 0 130880 0 ESTABLISHED localhost.localdomain.52603 localhost.localdomain.2011 34765 0 139264 0 ESTABLISHED localhost.localdomain.2011 localhost.localdomain.52603 139060 0 139060 0 ESTABLISHED localhost.localdomain.35345 localhost.localdomain.2001 65440 0 139264 0 ESTABLISHED localhost.localdomain.2001 localhost.localdomain.35345 139060 0 130880 0 ESTABLISHED localhost.localdomain.49022 localhost.localdomain.2001 130880 0 139264 0 TIME_WAIT localhost.localdomain.42797 localhost.localdomain.2001 130880 0 139264 0 TIME_WAIT localhost.localdomain.46312 localhost.localdomain.2001 130880 0 139264 0 TIME_WAIT TCP: IPv6 Local Address Remote Address Swind Send-Q Rwind Recv-Q State If --------------------------------- --------------------------------- ----- ------ ----- ------ ----------- ----- *.5432 *.* 0 0 128000 0 LISTEN *.sunrpc *.* 0 0 128000 0 LISTEN *.* *.* 0 0 128000 0 IDLE *.54002 *.* 0 0 128000 0 LISTEN *.55493 *.* 0 0 1049200 0 LISTEN *.lockd *.* 0 0 1049200 0 LISTEN *.53943 *.* 0 0 128000 0 LISTEN *.57055 *.* 0 0 128000 0 LISTEN *.login *.* 0 0 128000 0 LISTEN *.finger *.* 0 0 128000 0 LISTEN *.telnet *.* 0 0 128000 0 LISTEN *.shell *.* 0 0 128000 0 LISTEN *.60838 *.* 0 0 128000 0 LISTEN *.56894 *.* 0 0 128000 0 LISTEN *.53672 *.* 0 0 128000 0 LISTEN *.63720 *.* 0 0 128000 0 LISTEN *.ssh *.* 0 0 128000 0 LISTEN localhost.smtp *.* 0 0 128000 0 LISTEN *.80 *.* 0 0 128000 0 LISTEN *.2000 *.* 0 0 128000 0 LISTEN *.443 *.* 0 0 128000 0 LISTEN Active UNIX domain sockets Address Type Vnode Conn Local Addr Remote Addr ffffff0119f107b8 stream-ord 00000000 00000000 ffffff0119f10b68 stream-ord 00000000 00000000 ffffff0119214050 stream-ord 00000000 00000000 ffffff0119214400 stream-ord 00000000 00000000 ffffff0119214b60 stream-ord 00000000 00000000 ffffff0114119048 stream-ord 00000000 00000000 ffffff01141193f8 stream-ord ffffff011950e580 00000000 /tmp/dbus-3YiNfXlgwn ffffff01141197a8 stream-ord ffffff0119217e40 00000000 /tmp/dbus-7BNzAEnmYY ffffff0114119b58 stream-ord ffffff0114118e40 00000000 /var/run/mDNSResponder ffffff01138b2040 stream-ord 00000000 00000000 /var/run/dbus/system_bus_socket ffffff01138b23f0 stream-ord 00000000 ffffff0111d0e780 /var/run/dbus/system_bus_socket ffffff01138b27a0 stream-ord 00000000 00000000 /var/run/dbus/system_bus_socket ffffff01138b2b50 stream-ord 00000000 ffffff0111d0e780 /var/run/dbus/system_bus_socket ffffff0113059038 stream-ord ffffff0113835140 00000000 /var/run/.inetd.uds ffffff01130593e8 stream-ord 00000000 ffffff0112c5f880 /var/run/hald/dbus-9g2E5zdff9 ffffff0113059798 stream-ord 00000000 00000000 /var/run/hald/dbus-9g2E5zdff9 ffffff0113059b48 dgram ffffff01130b2e00 00000000 /var/run/in.ndpd_mib ffffff011306d030 stream-ord ffffff0112bb5280 00000000 /var/run/in.ndpd_ipadm ffffff011306d3e0 stream-ord 00000000 00000000 /var/run/hald/dbus-9g2E5zdff9 ffffff011306d790 stream-ord 00000000 00000000 /var/run/hald/dbus-9g2E5zdff9 ffffff011306db40 stream-ord 00000000 ffffff0112c5f880 /var/run/hald/dbus-9g2E5zdff9 ffffff0112fcb028 stream-ord 00000000 ffffff0112c5f880 /var/run/hald/dbus-9g2E5zdff9 ffffff0112fcb3d8 stream-ord 00000000 00000000 /var/run/hald/dbus-9g2E5zdff9 ffffff0112fcb788 stream-ord 00000000 ffffff0112c5f880 /var/run/hald/dbus-9g2E5zdff9 ffffff0112fcbb38 stream-ord ffffff0112fd4080 00000000 /tmp/.s.PGSQL.5432 ffffff01122c4020 stream-ord 00000000 00000000 /var/run/hald/dbus-F83hT9CGSX ffffff01122c43d0 stream-ord 00000000 ffffff0112c5f280 /var/run/hald/dbus-F83hT9CGSX ffffff01122c4780 stream-ord ffffff0112c5f280 00000000 /var/run/hald/dbus-F83hT9CGSX ffffff01122c4b30 stream-ord 00000000 00000000 ffffff0112294018 stream-ord 00000000 00000000 ffffff01122943c8 stream-ord ffffff0112c5f880 00000000 /var/run/hald/dbus-9g2E5zdff9 ffffff0112294778 stream-ord 00000000 00000000 ffffff0112294b28 stream-ord 00000000 00000000 ffffff0112278010 stream-ord ffffff01122c7880 00000000 /tmp/dbus-PuCCfO9I4C ffffff01122783c0 stream-ord 00000000 00000000 ffffff0112278770 stream-ord 00000000 00000000 ffffff0112278b20 stream-ord ffffff01122a0b40 00000000 /tmp/dbus-tfcmjjMClq ffffff0111d08008 stream-ord 00000000 00000000 ffffff0111d083b8 stream-ord 00000000 00000000 ffffff0111d08768 stream-ord ffffff01121a2b40 00000000 /tmp/dbus-cEAGQX2WDo ffffff0111d08b18 stream-ord ffffff0111d0e780 00000000 /var/run/dbus/system_bus_socketPostgresql is launched?
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Mark Rotteveel over 9 yearsThis message in the question is not thrown for wrong username/password (that would result in "FATAL: password authentication failed for user "xyz"" -
user2328488 over 9 years@PiotrKochanski I added result of the command
netstat -a. Explain me it (whether the reason in the first point of your response is covered). -
user2328488 over 9 years@SotiriosDelimanolis I added result of the command
netstat -a. Whether postgresql (as generally to learn it) is launched? -
Piotr Kochański over 9 yearsYes, Postgres runs. If you are sure that your user credentials are ok, check if TCP/IP connections are enabled, see cyberciti.biz/tips/…