Connect pgx to a PostgreSQL-dialect database

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

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

For more information, see Start PGAdapter.

  • pgx requires a username and password in the connection string. PGAdapter ignores these.
  • By default, PGAdapter disables SSL. pgx by default first tries to connect with SSL enabled. Disabling SSL in the connection request speeds up the connection process, as it requires one fewer round trip.
connString := "postgres://uid:pwd@APPLICATION_HOST:PORT/DATABASE_NAME?sslmode=disable"
ctx := context.Background()
conn, err := pgx.Connect(ctx, connString)
if err != nil {
  return err
}
defer conn.Close(ctx)

var greeting string
err = conn.QueryRow(ctx, "select 'Hello world!' as hello").Scan(&greeting)
if err != nil {
  return err
}
fmt.Printf("Greeting from Cloud Spanner PostgreSQL: %v\n", greeting)

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 the PostgreSQL pgx driver to a PostgreSQL-dialect database. Use Unix domain sockets for the lowest possible latency.

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

connString := "host=/tmp port=PORT database=DATABASE_NAME"
ctx := context.Background()
conn, err := pgx.Connect(ctx, connString)
if err != nil {
    return err
}
defer conn.Close(ctx)

var greeting string
err = conn.QueryRow(ctx, "select 'Hello world!' as hello").Scan(&greeting)
if err != nil {
    return err
}
fmt.Printf("Greeting from Cloud Spanner PostgreSQL: %v\n", greeting)

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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