dorm.contrib.prepared_stmts

Runtime control + introspection for PostgreSQL prepared statements.

API

dorm.contrib.prepared_stmts.set_threshold(threshold: int | None, *, alias: str = 'default') -> None

Update the PREPARE_THRESHOLD for alias at runtime.

Pass an integer to enable caching after threshold executions of the same SQL shape (psycopg's default is 5). Pass None to disable prepared-statement caching entirely. The change rebuilds the connection pool so existing checked-out connections finish their work without disruption; the next pool checkout uses the new threshold.

Side-effect: this re-invokes :func:dorm.configure to thread the new value through to the backend wrapper. Other DATABASES settings on alias are preserved.

dorm.contrib.prepared_stmts.active_prepared(*, alias: str = 'default') -> list[dict[str, Any]]

Return the rows of pg_prepared_statements on alias.

Each row carries name / statement / prepare_time / parameter_types / from_sql. The view is filtered to the current backend session — multi-connection pools may need to call this from a known session if reproducibility matters.

dorm.contrib.prepared_stmts.deallocate_all(*, alias: str = 'default') -> None

Run DEALLOCATE ALL on the active connection for alias.

Useful after a migration that altered a column type — psycopg's cached plan references the old type and the next execution raises cached plan must not change result type. Calling :func:deallocate_all from the post-migration hook clears the cache without bouncing the pool.