12.18. PostgreSQL Connector
The PostgreSQL connector allows querying and creating tables in an external PostgreSQL database. This can be used to join data between different systems like PostgreSQL and Hive, or between two different PostgreSQL instances.
To configure the PostgreSQL connector, create a catalog properties file
etc/catalog named, for example,
mount the PostgreSQL connector as the
Create the file with the following contents, replacing the
connection properties as appropriate for your setup:
connector.name=postgresql connection-url=jdbc:postgresql://example.net:5432/database connection-user=root connection-password=secret
Multiple PostgreSQL Databases or Servers
The PostgreSQL connector can only access a single database within a PostgreSQL server. Thus, if you have multiple PostgreSQL databases, or want to connect to multiple PostgreSQL servers, you must configure multiple instances of the PostgreSQL connector.
To add another catalog, simply add another properties file to
with a different name (making sure it ends in
.properties). For example,
if you name the property file
sales.properties, Presto will create a
sales using the configured connector.
The PostgreSQL connector provides a schema for every PostgreSQL schema.
You can see the available PostgreSQL schemas by running
SHOW SCHEMAS FROM postgresql;
If you have a PostgreSQL schema named
web, you can view the tables
in this schema by running
SHOW TABLES FROM postgresql.web;
You can see a list of the columns in the
clicks table in the
using either of the following:
DESCRIBE postgresql.web.clicks; SHOW COLUMNS FROM postgresql.web.clicks;
Finally, you can access the
clicks table in the
SELECT * FROM postgresql.web.clicks;
If you used a different name for your catalog properties file, use
that catalog name instead of
postgresql in the above examples.
PostgreSQL connector supports user impersonation. Please see User Impersonation for more details.
User impersonation can be turned with:
User impersonation in PostgreSQL connector is based on
For more details please visit: www.postgresql.org/docs.
PostgreSQL connector supports table and column statistics. The statistics are collected by PostgreSQL Database and retrieved by the connector. To collect statistics for a table, execute the following statement in PostgreSQL Database.
Please refer to PostgreSQL documentation for additional
Table Statistics Configuration Properties
||Enables table and column statistics.||
||Duration for which table and column statistics are cached.||
||Cache the fact that table statistics were not available.||