Connect psycopg2 to a PostgreSQL-dialect database

This page explains how to connect the PostgreSQL psycopg2 driver to a PostgreSQL-dialect database in Spanner. psycopg2 is a Python driver for PostgreSQL.

Verify that PGAdapter is running on the same machine as the application that is connecting using the PostgreSQL psycopg2 driver.

For more information, see Start PGAdapter.

connection = psycopg2.connect(database="DATABASE_NAME",
                              host="APPLICATION_HOST",
                              port=PORT)

cursor = connection.cursor()
cursor.execute('select \'Hello World\'')
for row in cursor:
  print(row)

cursor.close()
connection.close()

Replace the following:

  • APPLICATION_HOST: the hostname or IP address of the machine where PGAdapter is running. If running locally, you can use localhost.
  • PORT: the port number where PGAdapter is running. Change this in the connection string if PGAdapter is running on a custom port. Otherwise, use the default port, 5432.

Unix domain sockets

This section explains how to use Unix domain sockets to connect to a PostgreSQL-dialect database database. Use Unix domain socket connections when you need to have the lowest possible latency.

To use Unix domain sockets, PGAdapter must be running on the same host as the client application.

connection = psycopg2.connect(database="DATABASE_NAME",
                              host="/tmp",
                              port=PORT)

cursor = connection.cursor()
cursor.execute('select \'Hello World\'')
for row in cursor:
  print(row)

cursor.close()
connection.close()

Replace the following:

  • /tmp: the default domain socket directory for PGAdapter. This can be changed using the -dir command line argument.
  • PORT: the port number where PGAdapter is running. Change this in the connection string if PGAdapter is running on a custom port. Otherwise, use the default port, 5432.

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