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Postgres-XC Setup


Hi ,

Finally i have configured PG-XC in my local box .. Please find the below steps how to configure PG-XC .. 

Steps To Configure PG-XC
========================
Step 1
======
Download PG-XC Version 1.0 from the below link 

projects/postgres-xc/files/
Version_1.0/pgxc-v1.0.0.tar.gz/download

Step 2
======
mkdir -p /opt/Postgres-xc
chown -R postgres:postgres /opt/Postgres-xc/
tar -zxvf pgxc-v1.0.0.tar.gz

Step 3
======
Pre-Requistes
----------------
Readline,Bison,Flex
yum -y install readline*
yum -y install bison*
yum -y install flex*

./configure --prefix=/opt/Postgres-xc/
make
make install

Step 4
======
Setup of GTM  {Global Transaction Manager}
------------------------------
--------------------
-bash-4.1$ mkdir data_gtm
-bash-4.1$ chmod 700 data_gtm/
-bash-4.1$ /opt/Postgres-xc/bin/initgtm -Z gtm -D /usr/local/pgsql/data_gtm   

# It will create gtm.conf file under data_gtm location .. Then change the port of gtm server and listen_addresses if required.

Below are mine settings ..

nodename = 'GTM_Node'                      # Specifies the node name.
                                        # (changes requires restart)
listen_addresses = '*'                  # Listen addresses of this GTM.
                                        # (changes requires restart)
port = 7777  

-bash-4.1$ /opt/Postgres-xc/bin/gtm_ctl -Z gtm start -D /opt/Postgres-xc/data_gtm 
Server Started

Step 5
======
Setup of Co-Ordinator 
--------------------------
-bash-4.1$ mkdir data_coord1
-bash-4.1$ chmod 700 data_coord1/
-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl -D  /opt/Postgres-xc/data_coord1/ -o '--nodename coord1' initdb #It will initialize the PostgreSQL Cluster

# We need to configure this Co-Ordinator to connect as a node to GTM .. 
listen_addresses = '*'
port = 2345
gtm_host = 'localhost'                                                          
gtm_port = 7777                                                         
pgxc_node_name = 'coord1'                                                               
pooler_port = 2344                      
min_pool_size = 1                       
max_pool_size = 100                     
persistent_datanode_
connections = on                                            
max_coordinators = 16                   
max_datanodes = 16                      

-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl start -D /opt/Postgres-xc/data_coord1/ -Z coordinator -l /tmp/logfile_cord #Staring this initialized cluster as a PG-XC Co-Ordinator

Step 6
======
Setup of Data Node {Datanode1}
------------------------------
-------
-bash-4.1$ mkdir data_node1
-bash-4.1$ chmod 700 data_node1/
-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl -D  /opt/Postgres-xc/data_node1/ -o '--nodename datanode1' initdb #It will initialize the PostgreSQL Cluster

#We need to configure this Data Node as below..

listen_addresses = '*'
port = 1234
gtm_host = 'localhost'                  
gtm_port = 7777                 
pgxc_node_name = 'datanode1'                    

-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl start -D /opt/Postgres-xc/data_node1 -Z datanode -l /tmp/logfile_datanode1 #Starting this initialized cluster as a Data Node 

Step 7
======
Setup of Data Node {Datanode2}
------------------------------
-------
-bash-4.1$ mkdir data_node2
-bash-4.1$ chmod 700 data_node2/
-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl -D  /opt/Postgres-xc/data_node2/ -o '--nodename datanode2' initdb #It will initialize the PostgreSQL Cluster

#We need to configure this Data Node as below..

listen_addresses = '*'
port = 1233
gtm_host = 'localhost'                  
gtm_port = 7777                 
pgxc_node_name = 'datanode2'                    

-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl start -D /opt/Postgres-xc/data_node2 -Z datanode -l /tmp/logfile_datanode2 #Starting this initialized cluster as a Data Node 

Step 8
======
Creating Nodes @Co-Ordinator
------------------------------
-----
-bash-4.1$ ../bin/psql -p 2345
psql (PGXC 1.0.0, based on PG 9.1.4)
Type "help" for help.

postgres=# CREATE NODE datanode1 WITH ( TYPE = DATANODE , HOST = LOCALHOST , PORT = 1234 );
CREATE NODE

postgres=# CREATE NODE datanode2 WITH ( TYPE = DATANODE , HOST = LOCALHOST , PORT = 1233 );
CREATE NODE


Step 9
======
Distributing By Replication
------------------------------
-
-bash-4.1$ ../bin/psql -p 2345
psql (PGXC 1.0.0, based on PG 9.1.4)
Type "help" for help.
postgres=# CREATE TABLE DIST_REP(T INT) DISTRIBUTE BY REPLICATION TO NODE datanode1,datanode2;
CREATE TABLE

postgres=# INSERT INTO DIST_REP VALUES(GENERATE_SERIES(1,100))
;
INSERT 0 100

Explain Plan
--------------
postgres=# EXPLAIN ANALYZE SELECT * FROM DIST_REP;
                                                       QUERY PLAN                                                       
------------------------------
------------------------------
------------------------------------------------------------
 Data Node Scan on "__REMOTE_FQS_QUERY__"  (cost=0.00..0.00 rows=0 width=0) (actual time=0.797..0.864 rows=100 loops=1)
   Node/s: datanode1
 Total runtime: 0.899 ms
(3 rows)

Datanode 1
-------------
-bash-4.1$ ./psql -p 1234
psql (PGXC 1.0.0, based on PG 9.1.4)
Type "help" for help.

postgres=# SELECT COUNT(*) FROM DIST_REP;
WARNING:  Do not have a GTM snapshot available
WARNING:  Do not have a GTM snapshot available
 count 
-------
   100
(1 row)

Datanode 2
-------------
-bash-4.1$ ./psql -p 1233
psql (PGXC 1.0.0, based on PG 9.1.4)
Type "help" for help.

postgres=# SELECT COUNT(*) FROM DIST_REP;
WARNING:  Do not have a GTM snapshot available
WARNING:  Do not have a GTM snapshot available
 count 
-------
   100
(1 row)

Step 10
=======
Distributing by HASH {It's the similar behaviour what we have in PL/Proxy Hashing Mechanism}
------------------------------
------------------------------
--------------------------------
-bash-4.1$ ./psql -p 2345
psql (PGXC 1.0.0, based on PG 9.1.4)
Type "help" for help.

postgres=# CREATE TABLE DIST_HASH(T INT) DISTRIBUTE BY HASH(T) TO NODE datanode1,datanode2;
CREATE TABLE

postgres=# INSERT INTO DIST_HASH VALUES(1);
INSERT 0 1

--Inserted 1 to 4 Rows ..

Explain Plan
---------------
postgres=# EXPLAIN ANALYZE select * from dist_hash where t=1;
                                                      QUERY PLAN                                                      
------------------------------
------------------------------
----------------------------------------------------------
 Data Node Scan on "__REMOTE_FQS_QUERY__"  (cost=0.00..0.00 rows=0 width=0) (actual time=0.815..0.816 rows=1 loops=1)
   Node/s: datanode1
 Total runtime: 0.840 ms
(3 rows)


postgres=# EXPLAIN ANALYZE select * from dist_hash where t=4;
                                                      QUERY PLAN                                                      
------------------------------
------------------------------
----------------------------------------------------------
 Data Node Scan on "__REMOTE_FQS_QUERY__"  (cost=0.00..0.00 rows=0 width=0) (actual time=0.906..0.907 rows=1 loops=1)
   Node/s: datanode2
 Total runtime: 0.928 ms
(3 rows)


Datanode 1
-------------
-bash-4.1$ ./psql -p 1234
psql (PGXC 1.0.0, based on PG 9.1.4)
Type "help" for help.

postgres=# SELECT * FROM DIST_HASH;
WARNING:  Do not have a GTM snapshot available
WARNING:  Do not have a GTM snapshot available
 t 
---
 1
 2
(2 rows)

Datanode 2
-------------
-bash-4.1$ ./psql -p 1233
psql (PGXC 1.0.0, based on PG 9.1.4)
Type "help" for help.

postgres=# SELECT * FROM DIST_HASH;
WARNING:  Do not have a GTM snapshot available
WARNING:  Do not have a GTM snapshot available
 t 
---
 3
 4
(2 rows)

Step 11
=======
How to stop the PG-XC Nodes
---------------------------

Stop Co-Ordinator
--------------------
-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl stop -D /opt/Postgres-xc/data_coord1/ -Z coordinator -l /tmp/logfile_cord -mf

Stop Datanode
-----------------
-bash-4.1$ /opt/Postgres-xc/bin/pg_ctl stop -D /opt/Postgres-xc/data_node1 -Z datanode -l /tmp/logfile_datanode1 -mf

Stop GTM
------------
-bash-4.1$ /opt/Postgres-xc/bin/gtm_ctl -Z gtm start -D /opt/Postgres-xc/data_gtm

Will keep post more about this wonderful tool ..

--Dinesh
Labels:

Comments

  1. Shylu VkJuly 7, 2015 at 5:46 PM

    Hi! Good post! I have a few clarifications:
    1. So how does Postgres-XC achieve master-master & read-write scalability(especially write scalability).
    I created as per the above and when I created datasets in node1, it was not getting reflected on node2.
    2. Similarly, when I removed some datasets from node1, it was neither getting removed from the coordinator nor node2.

    ReplyDelete
    Replies
    1. Dinesh KumarJuly 8, 2015 at 12:31 AM

      Thanks for the comments.

      Which DISTRIBUTION method you have used. If you want to implement multi-master, we have to use DISTRIBUTED BY REPLICATION method

      Delete
    2. Shylu VkJuly 8, 2015 at 10:35 AM

      Yes, I have used DISTRIBUTED BY REPLICATION only. Still I don't see changes made on Node 1 getting reflected on Node 2.
      Its goes like this:
      1. Any changes I make in coordinator, its getting reflected on all three - Coordinator, Node 1, Node 2.
      2. Changes made in Node 1 are getting reflected on - Node 1 & Coordinator. (Not in Node 2)
      3. Changes made in Node 2 are getting reflected on - Node 2 alone (Not in Coordinator & Node 1)

      It's like Node 2 is partially disconnected. I checked the .conf files on all four - GTM, Coordinator, Node 1 & Node 2. Everything seems to be perfect there.

      Thanks in advance!

      Delete
    3. Dinesh KumarJuly 8, 2015 at 10:18 PM

      Hi

      If i remember correctly,

      Distributed by replication is for read scale => Use coordinator to do DML, and fetch records from individual nodes
      Distributed by hash is for write scale => Use nodes to do DML, and fetch records from Coordinator.

      -Dinesh

      Delete
    4. Shylu VkJuly 9, 2015 at 11:46 AM

      Thanks Dinesh! Tried HASH Distribution, that seems to have done the trick and it's working perfectly.

      Delete
  2. AnonymousSeptember 29, 2015 at 12:00 PM

    Hi Dinesh,
    I have configured two gtm (gtm1,gtm2) in two different machine using postgres-xc. And configured coordinator1,datanode1 in gtm1 machine and coordinator2,datanode2 in gtm2 machine. I have logged in both coordinator servers and created the datanode1 and datanode2 in both server. When i try to create the tables using the both node i am getting the error "Failed to get Pooled connection" and when i check the datanode1 log file found the error like this "unexpected EOF on client connection" . Please help me on this.

    ReplyDelete
    Replies
    1. Dinesh KumarSeptember 29, 2015 at 10:14 PM

      Oh. Are these two GTMs are independent.

      Delete
    2. AnonymousOctober 5, 2015 at 2:31 PM

      Yes Dinesh.. gtm1 is in separate server and Gtm2 is in separate server.

      Delete
  3. Jonah POctober 16, 2024 at 9:23 PM

    Hi nice reading yourr blog

    ReplyDelete

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