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psycopg3 ​

psycopg3 is the recommended PostgreSQL adapter for Python.

Connection pooling ​

psycopg3 includes its own connection pool (psycopg_pool). Client-side pooling is still useful when connecting through halephant. It saves you the SCRAM authentication and startup handshake on every request. Size the pool to match your application's concurrency, not the number of backend connections you expect to need. Halephant handles the server-side multiplexing.

Prepared statements ​

psycopg3 automatically prepares queries after prepare_threshold executions (default 5). This works transparently with halephant's prepared statement cache, so you don't need to change anything.

SSL ​

Halephant doesn't support TLS yet. Set sslmode=disable in the connection string or as an environment variable:

connection.py
python
conn = await psycopg.AsyncConnection.connect(
    "host=halephant port=6432 dbname=myapp user=myapp sslmode=disable"
)

Read-only transactions ​

Set read_only=True on the connection to make all implicit transactions read-only:

connection.py
python
conn = await psycopg.AsyncConnection.connect(conninfo, autocommit=False)
conn.read_only = True
# All subsequent queries use BEGIN READ ONLY.

For per-transaction control:

connection.py
python
async with conn.transaction() as tx:
    # This transaction inherits conn.read_only.
    await conn.execute("SELECT ...")

For autocommit connections, set the session default:

connection.py
python
conn = await psycopg.AsyncConnection.connect(conninfo, autocommit=True)
await conn.execute("SET default_transaction_read_only = on")

Or use a dedicated read-only user with default_transaction_read_only = on configured in halephant. See the read replica guide for details.