Could somebody help me understand how I would go about setting up postgresql's mysql_fdw? I'm looking at https://github.com/EnterpriseDB/mysql_fdw, and I not sure what the first step is.
I was able to do it the following way.
Installing the package:
sudo apt-get install postgresql-9.5-mysql-fdw
Adds the extension in the Database:
CREATE EXTENSION mysql_fdw;
Add the mysql server to postgresql:
CREATE SERVER mysql_server FOREIGN DATA WRAPPER mysql_fdw OPTIONS (host 'localhost', port '3306');
Create a user to access the database:
CREATE USER MAPPING FOR postgres SERVER mysql_server OPTIONS (username 'root', password 'passwordToConnect');
Import a Schema table from another server
IMPORT FOREIGN SCHEMA mySchema LIMIT TO (tableName) FROM SERVER mysql_server INTO public;
Imports all Schema tables from another server
IMPORT FOREIGN SCHEMA mySchema FROM SERVER mysql_server INTO public;
I hope I have helped.
You linked to the ODBC foreign data wrapper odbc_fdw. You can use it for MySQL, but if you just want MySQL you should use mysql_fdw instead. That way you don't have to mess with ODBC.
Handily, the README for mysql_fdw contains detailed instructions for installation and configuration, so you should be fine setting it up; I won't duplicate those instructions here.
Related
hoping for some help as I am very new to postgresql admin!
I have 2 servers added to pgadmin, server 1 is a hosted db on Heroku the other is local to the server
I want to add the Heroku db as foreign tables to the local db
can I link these 2 servers? as so far I have failed
I have the fdw extension setup locally, and I am able to use it across three local dbs ok, do I need the extension also setup on the Heroku db?
I have setup the fdw server as
host localhost --- should this be the Heroku host path? or is this ok since I have added - --server local? I get fsrvoption error if I add actual host path
dbname dbname
port 5432
and then setup user
user username
password password
any help appreciated!
mal
You don't have to set up anything on the remote server to access it via foreign data wrapper; the foreign data wrapper will access the remote database as a regular database client.
Once you hace set up postgres_fdw correctly, you can use it to access tables on the remote server just as if they were local tables. A foreign table is a bit like a view in some respects.
Maybe it helps to understand the objects involved:
The foreign data wrapper encapsulates the code to access the remote data source (PostgreSQL client).
The foreign server wraps the connect string for the remote database.
The user mapping contains the credentials for a user to access the foreign server.
The foreign table describes a table on the remote server.
You can use the command IMPORT FOREIGN SCHEMA to automatically define foreign tables for all (or part) of the tables in a schema on the remote server.
Once the foreign tables are defined correctly, you can use them in SQL statements just like local tables, but you will actually read and write data on the remote server.
After some debugging, the problem turned out to be this:
Creating the foreign server using pgAdmin caused a strange error with fsrvoption (running CREATE SERVER via the query tool worked).
Creating the foreign server with localhost rather than the correct server address unsurprisingly gave the error that the database doesn't exist.
Cant connect from postgresql server to hive databases on remote server.
Tried using the following queries but doenst work. Connection established but no response back from hive server.
--create extension postgres_fdw;
DROP USER MAPPING IF EXISTS FOR CURRENT_USER SERVER data_db;
drop server data_db;
create server data_db
foreign data wrapper postgres_fdw
options (host 'net.com' , port 'hiveport' , SSLMODE 'allow', dbname 'datah');
create user mapping for current_user
server data_db
options(user 'user', password 'password');
drop schema app;
create schema app;
import foreign schema public
from server data_db
into app;
The result was unknown expecting authentication request from the server (SQL state 08001).
I would like to be able to establish a connection to the hive database clusters using the fdw from postgresql to import selective data.
Thank you very much in advance and best regards!
postgres_fdw is for connecting to other PostgreSQL instances. Hive doesn't use the same wire protocol as PostgreSQL does, so surely postgres_fdw would not be expected to connect to it successfully. Perhaps you can try https://github.com/youngwookim/hive-fdw-for-postgresql or https://sourceforge.net/projects/hadoopfdw/.
I have a postgresql db at home and one on the cloud. I'd like to add my home db to the cloud db so I can query easily between databases. How can this be done? Without using dblink http://www.postgresonline.com/journal/archives/44-Using-DbLink-to-access-other-PostgreSQL-Databases-and-Servers.html
My home db will use a dynamic ip provider (can I add a dynamic ip address such as myhomedb.dedyn.io to postgresql settings?)
I'm stating all this in case there are any issues. My home db will only be used to update massive amount of data but isn't mission critical (as we know cloud computing isn't cheap).
Thanks in advance.
Looks like postgres-fdw is the way to go: https://www.postgresql.org/docs/current/postgres-fdw.html
First install the extension:
CREATE EXTENSION postgres_fdw;
Then create a foreign server using CREATE SERVER. In this example we
wish to connect to a PostgreSQL server on host 192.83.123.89
listening on port 5432. The database to which the connection is made
is named foreign_db on the remote server:
CREATE SERVER foreign_server
FOREIGN DATA WRAPPER postgres_fdw
OPTIONS (host '192.83.123.89', port '5432', dbname 'foreign_db');
A user mapping, defined with CREATE USER MAPPING, is needed as well
to identify the role that will be used on the remote server:
CREATE USER MAPPING FOR local_user
SERVER foreign_server
OPTIONS (user 'foreign_user', password 'password');
Now it is possible to create a foreign table with CREATE FOREIGN
TABLE. In this example we wish to access the table named
some_schema.some_table on the remote server. The local name for it
will be foreign_table:
CREATE FOREIGN TABLE foreign_table (
id integer NOT NULL,
data text
)
SERVER foreign_server
OPTIONS (schema_name 'some_schema', table_name 'some_table');
It's essential that the data types and other properties of the columns
declared in CREATE FOREIGN TABLE match the actual remote table.
Column names must match as well, unless you attach column_name options
to the individual columns to show how they are named in the remote
table. In many cases, use of IMPORT FOREIGN SCHEMA is preferable to
constructing foreign table definitions manually.
I'm using postgres 9.5.9. I have setup a FDW to a remote host. This all works ok. But when a new table is added to the remote host schema, the FDW does not see it. Usually I can do this...
IMPORT FOREIGN SCHEMA public LIMIT TO(new_table_name) FROM SERVER production INTO public;
But for some reason this isnt importing it this time.
> IMPORT FOREIGN SCHEMA public LIMIT TO(new_table_name) FROM SERVER production INTO public;
IMPORT FOREIGN SCHEMA
>
But then it doesnt see it
> \d new_table_name
Did not find any relation named "new_table_name".
How can I find what the cause of this is? I dont see anything in the logs about it.
EDIT
This ended up being a connection issue.
Can I change PostgreSQL database schema in WSO2 IS? For default, it is public, but I want to change it to my custom one.
Please, help.
EXPLANATION:
I connected PostgreSQL database as primary database into WSO2 IS. First run wso2server.bat with -Dsetup parameter and all database tables was created in public schema of connected database.
I hope, that I can change default public schema to my own, for example wso2.
Yes it's possible. You have to modify the db scripts to use the custom schema with following line at the scripts.
SET search_path TO wso2;
Then set the search_path to include the schema you are using.
Refer the post here for more detailed steps.